Exam 1

T cells that recognize both MHC and self-antigens can cause autoimmune diseases.

In tissue.

BCR binds with much stronger affinity than TCR.

The white pulp of the spleen.

Through the release of toxic products and enzymes from phagocytic cells.

In the bone marrow.

To ensure T cells can test their receptors.

Macrophages are innate immune cells.

The interaction of the TCR complex with MHC and antigen.

The co-stimulation signal between CD28 and B7.

Neutrophils are short-lived.

To provide help for B cell antibody production, particularly IgE.

TCR recognize only linear peptides that are complexed with MHC.

The B Cell Receptor has 2 antigen binding sites.

Co-stimulation.

Chemokines attract other cells.

Yes, people without a spleen can still fight blood infections.

In the bone marrow (B M).

In the periphery.

TdT adds nucleotides to the ends of gene segments during the recombination process.

The BCR consists of a membrane-bound antibody associated with signaling molecules.

The thymus.

Innate immune response receptors are non-clonal and not unique, whereas adaptive immune response receptors are clonal and unique.

Immunological memory is the ability of the immune system to respond more rapidly and effectively to pathogens that have been encountered previously.

Chemokines and their receptors, as well as adhesion molecules, guide T cell migration.

Genetic differences in antigens can cause the immune system to recognize transplanted tissue as foreign and attack it.

No, they require co-receptors and accessory signaling molecules for proper functioning.

The α and β chains of the main TCR complexed with signaling proteins.

It can lead to meningitis.

The ability of the receptor to transmit a signal.

They allow the expression of non-thymic antigens, such as those from other organs.

MHC class I molecules.

Type I interferons.

To target and kill infected cells.

MHC + Peptide, B7, Adhesion molecules (ICAM-1).

Recognizing MHC molecules is crucial for T cells to identify and respond to antigens presented by these molecules.

Rearrangement.

V (variable), D (diversity), J (joining), and C (constant).

The spleen fights blood infections.

From blood to tissue.

Microbes have a variety of ways to gain access to the inside of our cells.

It affects the peptide-binding region, influencing the immune response.

Through lymph circulation.

V(D)J recombination.

They undergo ignorance or anergy.

Effector cells are supposed to die at the end of the response.

The cutaneous immune system is the immune system associated with the skin, providing the first line of defense against pathogens.

Blocking CTLA-4 and PD-1 can enhance T cell responses against cancer cells, making them important targets in cancer immunotherapy.

TLR 2

Autoimmune diseases, where the immune system attacks the body's own cells.

VDJ recombinase.

To promote tissue repair.

Constantly testing for foreign substances.

Cells follow chemical signals, often referred to as 'bread crumbs,' to the site of infection.

CD3.

Most will die and never interact with the receptor they code for.

Dendritic cells.

The receptor rearrangement process.

It will try to make different types of light chains as long as the 3' end and 5' end are intact for its rearrangement.

Yes, innate immune response receptors have access to DNA.

MHC interaction.

The first cells to be affected by sun exposure are typically skin cells, including keratinocytes and Langerhans cells.

They enhance the neutrophil response.

The receptor rearrangement process.

To promote inflammation.

CD8 T cells are cytotoxic and will kill any cell that is presenting its antigen.

Without co-stimulation, lymphocytes cannot be fully activated.

Cell-mediated immunity.

We must clear all microbial reservoirs, including our own infected cells.

Because bone is rigid and does not back down to swelling.

To assist other immune cells by releasing cytokines and enhancing the immune response.

T cell migration is the process by which T cells move from their site of origin to various tissues in the body to perform immune functions.

The production of an intact receptor.

They trigger the innate immune response.

A pro cell in lymphocyte maturation does not yet have any part of the receptor.

In the intestinal and pulmonary epithelium.

Through tissue or blood.

TLR 5

The variable domain is responsible for binding to antigens and varies from one receptor to another.

Lymphocyte development.

It is the stage where selection occurs.

They, together with CD3, transmit the signal into the cell and initiate signal transduction.

CTLA-4 is an immune checkpoint receptor that downregulates immune responses by inhibiting T cell activation.

The signaling molecules are Igα and Igβ.

Positive selection ensures that T cells can recognize MHC molecules.

By binding to them and preventing their interaction with host cells or marking them for destruction by other immune cells.

They are pro-inflammatory, activate macrophages, and provide help for B cell antibody production.

A pre cell in lymphocyte maturation has one of the receptor chains.

To present peptide fragments to T cells, enabling the immune system to detect and respond to pathogens.

To the B cell zone.

Igα, Igβ, CD19, CD21, CD81

To limit damage and restore function.

To kill infected cells and cancer cells.

A state where B cells exist but are never active and generally unresponsive.

Igα and Igβ transmit the signal into the cell and start signal transduction.

T cell receptors recognize antigens from genetically different tissues, leading to transplant rejection.

It ensures that antibodies can precisely target and neutralize specific pathogens without affecting the host's own cells.

No, the innate immune system does not have the ability to remember pathogens; this is a characteristic of the adaptive immune system.

B7 is a costimulatory molecule found on antigen-presenting cells that binds to CD28 on T cells to provide the necessary second signal for T cell activation.

To suppress T cell responses.

Cancer cells are destroyed.

The variable regions of the B Cell Receptor are crucial for antigen specificity and binding.

Lymphocytes constantly move from blood to lymph until they are activated or killed.

CD3, CD4, CD8

Y and D are constant regions.

Because these interactions are essential for the proper activation of T cells.

To transmit the signal into the cell and initiate signal transduction.

Antigens are processed by antigen-presenting cells (APCs) and presented on their surface bound to MHC molecules.

To be captured and presented to T cells.

T cell migration is crucial for the immune response as it allows T cells to reach sites of infection or inflammation and perform their roles in immune surveillance and response.

Checkpoints ensure that only lymphocytes with functional and non-self-reactive receptors survive and mature.

BCR recognize 3D structures and macromolecules in their native conformation, while TCR recognize only linear peptides complexed with MHC.

Adhesion molecules help T cells adhere to the endothelium of blood vessels and migrate into tissues.

Dendritic cells present the antigen to T cells.

Nearly all adults are infected with HSV-1.

The production of an intact receptor.

BCR has a smaller Kd compared to TCR.

They are crucial for the activation process, and it is important to know which cell each molecule is found on (T cell or APC).

The standard antiviral response.

MHC class II molecules.

To recognize and bind to antigens presented by other cells.

The cytokines released by the APC, which tell T_H cells what form of helper T cell to become.

Three signals.

Our own antigens.

They undergo apoptosis and are removed from the T cell repertoire.

Recognizing self-antigens can lead to autoimmunity, where the immune system attacks the body's own tissues.

TGF-β, IL-1, IL-6, IL-23

IgM alone.

A tool that allows them to pass the immune response temporarily.

An aircraft stopping dead on an aircraft carrier.

The consequences are more severe, such as inflammation around the brain and spinal cord leading to meningitis.

It can cause long-term brain damage.

Effector cells perform their specific functions to eliminate pathogens.

PD-1 is an immune checkpoint receptor that inhibits T cell activity to prevent autoimmunity and reduce inflammation.

Innate immune response receptors are located everywhere in the body.

Igα and Igβ are similar to CD3 in their function of transmitting signals into the cell.

T cells originate in the bone marrow and mature in the thymus.

The BCR consists of 2 heavy chains and 2 light chains.

In the bone marrow.

IL-4

The developmental stage of the cell.

Before encounter with antigen.

The damage is usually nominal.

Terminal deoxynucleotidyl transferase (TdT).

The α chain.

Receptor editing is a process during lymphocyte maturation where the cell changes its receptor to avoid self-reactivity.

Molecules or molecular structures that are recognized by antibodies and trigger an immune response.

They are eliminated because they cannot effectively participate in the immune response.

It acts as the first line of defense against pathogens entering through the skin.

A set of genes that code for proteins on the cell surface which help the immune system recognize foreign substances.

To clear the foreign antigen and its source.

Cell migration is the process by which cells move from one location to another, often following chemical signals.

Multiple antigens at the same time.

T cells and Antigen-Presenting Cells (APCs).

High affinity binding in primary lymph tissue.

To bind to antigens and neutralize them or mark them for destruction by other immune cells.

Lymphocytes that fail multiple checkpoints during maturation undergo apoptosis (cell death).

Double-negative, double-positive, and single-positive.

They are Gram-negative bacteria.

BCR recognize 3D structures and macromolecules in their native conformation.

Pro-inflammatory and pro-repair.

The variable domain, responsible for binding to antigens, and the constant domain, responsible for structural and effector functions.

Any antigen that is not our own or wasn’t screened for.

The constant domain is structural and responsible for effector functions, and is virtually the same from one receptor to another.

Macrophages and plasma cells.

Functions include tumor destruction, recognition of heat-shock proteins on damaged or infected cells, and epithelial surveillance for UV damage, infection, and cancer.

Chronic inflammation and tissue damage.

V(D)J recombination generates the diversity of antibodies necessary for the immune system to recognize a wide array of antigens.

Early in life.

It allows them to temporarily evade the immune response.

In the peptide-binding region.

Yes, it can deal with different infections simultaneously, such as responding to COVID-19 and Hepatitis B at the same time.

The β chain.

AIRE allows CECs to express non-thymic antigens.

Both are phagocytes.

Both CTLA-4 and PD-1 help maintain immune tolerance by inhibiting T cell activation and preventing overactive immune responses.

Negative selection eliminates T cells that recognize self-antigens presented by MHC molecules.

T Cell Receptor including CD3 and CD4/8, CD28, Integrins (LFA-1).

TLR 4

Approximately 10% of total T cells.

CD4 T cells are helper T cells and will tell other cells what to do.

An exaggerated immune response to a harmless substance.

The rearrangement of gene segments that encode receptor proteins.

IgM and IgD.

In the periphery.

Nearly all adults are infected with Epstein-Barr virus.

Th1, Th2, Th17

Cytotoxic T Lymphocyte.

Interleukin-1 (IL-1) is a key cytokine involved in innate immunity.

Each T cell recognizes something completely different from all of the others.

Negative selection eliminates T cells that strongly bind to self-antigens, preventing autoimmunity.

We are protected against pathogens, can fight off infection, cancer cells are destroyed, and we recognize and ignore harmless antigens.

Specialized cells that engulf and digest microbes and cellular debris.

Peptide binding to MHC molecules is crucial for the immune system to recognize and respond to pathogens.

Activated T cells proliferate and become effector cells.

A foreign antigen.

Both maternal and paternal alleles are expressed, contributing to the diversity of MHC molecules.

Adding or deleting nucleotides at the junction site of different segments.

The entry of bacteria into the body.

Cell-mediated immunity involves T cells and does not rely on antibodies, whereas humoral immunity involves B cells and the production of antibodies.

The follicle.

The RAG (Recombination Activating Gene) enzyme complex.

The ligand for E and P-selectin and the integrins LFA-1 and VLA-1.

The Fab fragment and the Fc fragment.

In the cytoplasm.

Activated T cells secrete cytokines that help regulate and amplify the immune response.

Cytokines such as IL-2, produced by helper T cells, promote the proliferation and differentiation of CTLs.

MHC molecules typically bind to protein peptides.

Chemokines and cytokines are key signals that direct cell migration.

Receptor gene expression refers to the process by which specific genes are transcribed and translated to produce receptor proteins on the surface of cells.

Proteins.

How so many receptors are coded for by such a limited genome.

They present intracellular antigens to cytotoxic T cells, triggering an immune response.

The thymus undergoes involution, meaning it gradually shrinks and becomes less active in producing new T cells.

IgA.

The primary function of macrophages is to phagocytose (engulf and digest) pathogens, dead cells, and cellular debris.

Cyclic AMP (cAMP) is a common second messenger.

Yes, but each MHC molecule binds a different range of peptides.

Mucus is driven upward constantly to expel or swallow it, trapping and protecting against pathogens.

IgE.

Cells communicate through receptors that recognize and bind molecules called ligands.

The T cell will activate and become an effector cell.

They present antigens to T cells.

By presenting antigens to T cells, which then initiate an immune response against the detected pathogen.

It needs to get to the secondary lymphoid organs.

It recognizes and ignores them.

10-30 amino acids.

Macrophages engulf pathogens, process them, and present antigens to T cells.

They all have high infection rates among adults.

The recognition of antigens by T cell receptors (TCRs) triggers the expansion of T cells.

Recognition of antigen presented by MHC class I molecules on the surface of infected or abnormal cells.

High levels of E-selectins, P-selectins, ICAM-1, and VCAM-1.

Signal transduction is the process by which a cell converts an extracellular signal into a functional response.

An immunological synapse is the interface between an antigen-presenting cell (APC) and a T cell where signaling and communication occur.

No, but they provide significant protection.

An antigen-presenting cell (APC) and a T cell.

The skin.

To facilitate communication and signaling between the antigen-presenting cell and the T cell, leading to T cell activation.

Lymph nodes swell because B and T cells are cloning (proliferating) in response to recognizing an antigen.

Through competitive exclusion by covering binding sites and competing for nutrients.

Through phagocytosis, endocytosis, and pinocytosis.

T cell exhaustion is commonly observed in chronic infections and cancer.

Integrins are cell surface receptors that mediate adhesion to the extracellular matrix, facilitating cell movement.

Mucus helps wash surfaces and can propel microorganisms and viruses to areas where they can be eliminated.

A specialized type of dendritic cell found in the skin.

Without CD4 T cell help, CD8 T cells may have a reduced ability to proliferate and effectively kill target cells.

Lymphatic vessels, primary (generative) lymphoid organs, and secondary (peripheral) lymphoid organs.

Signal transduction is important because it allows cells to respond to their environment and communicate with other cells, ensuring proper functioning and coordination within an organism.

Helper T cell cytokines, such as Interferon-gamma (IFN-γ), activate macrophages to enhance their microbicidal activity.

Substances that induce fever.

CD28 is a receptor on T cells that binds to B7 on antigen-presenting cells, providing a crucial costimulatory signal required for full T cell activation and survival.

To the T cell zone.

Recombinase-activating Genes (RAG-1 and RAG-2).

Gene segment recombination is the process by which B cells rearrange their DNA to create unique antibodies.

Dendritic cells.

The T cell zone.

IL-2 promotes the proliferation of activated T cells, enhancing the immune response.

8-11 amino acids.

Cytokines recruit more immune cells to the site of infection.

IL-2 enhances the cytotoxic activity of natural killer (NK) cells.

MHC molecules present microbial antigens to effector cells for recognition.

After the antigen is eliminated, most of the expanded T cells undergo apoptosis, leading to a decline in their numbers.

The two main types of T Cell Receptors are alpha-beta (αβ) TCRs and gamma-delta (γδ) TCRs.

It binds to the antigen.

Chemokines attract immune cells to sites of infection or injury.

They can both present antigens and phagocytose.

MHC class I molecules present endogenous antigens (from within the cell) to CD8+ T cells, while MHC class II molecules present exogenous antigens (from outside the cell) to CD4+ T cells.

By detecting specific antigens presented on the surface of these cells by MHC class I molecules.

Cells move by extending protrusions like lamellipodia and filopodia, adhering to the extracellular matrix, and contracting their cytoskeleton to pull themselves forward.

They migrate to the lymph nodes where they present the antigen to T cells.

It prevents pathogens from binding.

1. Bind to a ligand 2. Signal transduction

Interleukin-2 (IL-2) is a key cytokine produced by Helper T cells.

It makes nutrients unavailable for pathogens.

They present antigens to CTLs, allowing them to recognize and target infected or abnormal cells.

It regulates B cell activity

Hypervariable Regions (HV) or Complementarity Determining Regions (CDR).

They are crucial for inducing a strong and specific immune response, making them a target for vaccine strategies.

All white blood cells except most lymphocytes.

Infection and disease, as the pathogen can proliferate unchecked.

Cells that present antigens to T cells to activate an immune response.

Combinatorial diversity.

They are segments, not complete genes.

They continue to move between blood and lymph until they are either activated or killed.

T cells undergo clonal expansion, where they rapidly proliferate to increase the number of T cells specific to the antigen.

Two copies or alleles.

Cytokines mediate and regulate immune and inflammatory responses in innate immunity.

MHC molecules present antigens in a membrane-bound form.

Mechanisms built in to ensure that each lymphocyte expresses only one antigen-specific receptor.

An entire light chain and the corresponding heavy chain variable region and first constant region.

Cell migration is crucial for immune responses, allowing immune cells to travel to sites of infection or injury to perform their functions.

Each lymphocyte will express either all maternal or all paternal receptors, but not a mix.

Interferon-gamma (IFN-γ).

Common features include poor effector function, sustained expression of inhibitory receptors (such as PD-1, CTLA-4), and a distinct transcriptional profile.

Th2 cells are involved in humoral immunity and help activate B cells to produce antibodies.

MHC polymorphism increases the range of antigens that can be presented to T cells, enhancing the ability of the immune system to recognize and respond to a diverse array of pathogens.

It determines the class and effector functions of the antibody.

Both innate and adaptive responses

Th17 cells are involved in the defense against extracellular bacteria and fungi and contribute to inflammatory responses.

After leaving the bone marrow, monocytes circulate in the blood and then migrate into tissues where they differentiate into macrophages or dendritic cells.

Interleukin-17 (IL-17).

In order for the body to mount an appropriate immune response.

V, D, and J segments.

CTL (Cytotoxic T Lymphocyte) activity

By presenting processed antigens on their surface along with necessary co-stimulatory signals.

D-J rearrangement first, then V-DJ.

T cells become fully mature in the thymus.

At the DNA level.

It has a restricted repertoire and may recognize antigens without MHC restriction.

They can recognize non-peptide antigens.

Dendritic cells, B cells, and macrophages.

Phagocytes, antigen-specific cytotoxic T-lymphocytes, and various cytokines.

No, receiving a second shot doesn't mean you won't get sick.

Intracellular infection.

They are where the microbiome is chopped.

B cells.

No, unlike MHC, a cell can only express one allele.

It is the site where B cells proliferate, differentiate, and mutate their antibody genes.

The binding zone of the MHC molecule holds the antigen in place so it doesn't fly away.

Polygeny refers to the presence of multiple genes within an individual that encode for proteins with similar functions, such as the multiple MHC (Major Histocompatibility Complex) genes.

T cells that express both CD4 and CD8 co-receptors during a stage of their development.

Memory T cells persist after the decline phase and provide a faster and more robust response upon re-exposure to the same antigen.

Mononuclear phagocytes are a type of immune cell that includes monocytes and macrophages, which are involved in the detection, phagocytosis, and destruction of bacteria and other harmful organisms.

The Major Histocompatibility Complex (MHC) presents peptide fragments of antigens on the surface of antigen-presenting cells, which are then recognized by T Cell Receptors (TCRs).

They enter the peripheral bloodstream and lymphoid organs to perform immune functions.

Effector cells, such as T cells, are involved in MHC-associated antigen presentation.

The two-signal requirement for lymphocyte activation involves the recognition of an antigen by the lymphocyte receptor (Signal 1) and a co-stimulatory signal provided by antigen-presenting cells (Signal 2).

Binding to its cellular receptor reduces the expression of the S1P receptor.

CD4 T cells secrete cytokines that enhance the activation and proliferation of CD8 T cells.

Receptor gene expression involves genetic recombination processes that generate a diverse repertoire of receptors, enabling the immune system to recognize a wide array of antigens.

Inflammation

Treg cells help maintain immune tolerance and prevent autoimmune diseases.

Fever.

Transforming growth factor-beta (TGF-β) and Interleukin-10 (IL-10).

While CD8 T cells can function independently to some extent, their efficiency and longevity are significantly enhanced by the help of CD4 T cells.

The main receptor binds the ligand.

The B Cell Receptor is approximately twice as large as the T Cell Receptor.

Polymorphism refers to the presence of multiple alleles at a gene locus, resulting in a high degree of variability in MHC molecules.

They go to the site with the source of the activating antigen and carry out their effector functions.

IL-12 and IFN-γ

B cells present antigens to T cells to help initiate an immune response.

They undergo a series of maturation steps, including positive and negative selection.

Yes, every single cell with a nucleus has MHC class I molecules.

Red blood cells (RBCs).

Clonal expansion refers to the rapid multiplication of T cells that have recognized a specific antigen.

Cell migration is the process by which cells move from one location to another, often in response to specific signals.

In the cytoplasm.

By the B cell receptor (BCR).

MHC + peptide

The immune system induces apoptosis in most of the expanded T cells, ensuring that their numbers return to normal after the infection is cleared.

Leukocytes, including T cells, B cells, and macrophages, are primarily involved in cell migration during an immune response.

Receptor gene expression is crucial for the development and function of immune cells, allowing them to recognize and respond to specific antigens.

PD-1 and CTLA-4 are commonly expressed inhibitory receptors on exhausted T cells.

Interleukin-4 (IL-4), Interleukin-5 (IL-5), and Interleukin-13 (IL-13).

B cells and T cells are primarily involved in receptor gene expression, producing B cell receptors (BCRs) and T cell receptors (TCRs) respectively.

To bring B and T cells in contact with antigens.

A signal, often in the form of a molecule such as a hormone or neurotransmitter, initiates signal transduction.

NK cells target and kill cells that are abnormal or infected, not microbes directly.

B-2 cells (Follicular B cells), B-1 cells, and Marginal zone B cells.

During lymphocyte maturation, receptor gene expression ensures that each lymphocyte expresses a unique receptor, which is essential for the specific recognition of antigens.

Other lymphoid organs, such as the spleen and lymph nodes, help compensate for the reduced activity of the thymus.

S1P receptor expression is restored while L-selectin and CCR7 are turned off, drawing the activated cell out of the lymph node.

They help teach our immune response what is good and bad.

Thymic cortical epithelial cells.

The interaction between B7 and CD28 is essential for the activation of T cells, as it provides the necessary costimulatory signal that complements the antigen-specific signal from the T cell receptor.

Cell-mediated immunity is an immune response that does not involve antibodies but rather the activation of phagocytes, antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in response to an antigen.

The V (variable), D (diversity), and J (joining) gene segments.

They inhibit each other as they have opposing functions.

To the site of infection.

Lysozyme degrades peptidoglycan.

They present intracellular antigens to cytotoxic T cells, triggering an immune response.

Lipids and nucleic acids.

Through T cell receptors (TCRs) that bind to specific antigens presented by MHC molecules.

Only in lymph tissues.

T cells recognize antigens presented by other cells via MHC molecules, while B cells recognize free-floating antigens directly.

Yes, both organic and inorganic compounds can elicit an immune response.

Th1 cells are involved in cell-mediated immunity and help activate macrophages and cytotoxic T cells.

NK cells are activated by the presence of stress-induced ligands on target cells and the absence of MHC class I molecules.

Adaptive immunity provides a specific response to pathogens and has memory for faster response upon re-exposure.

Before exposure to the antigen.

The T cell receptor:MHC/antigen interaction.

Cell migration, inflammation, and activation of the adaptive response.

Beta (Β, β)

Regulatory T cells (Tregs) help maintain immune tolerance and prevent autoimmune responses by suppressing the activity of other immune cells.

Psi (Ψ, ψ)

Approximately 20% to 50% of adults in the United States are infected with HSV-2.

Cross-presentation is the process by which certain antigen-presenting cells, like dendritic cells, present exogenous antigens on MHC class I molecules.

To present antigens to T cells and activate them.

T cell progenitors migrate from the bone marrow to the thymus.

It is the source of lymphocyte receptor diversity.

Positive selection ensures that T cells can recognize self-MHC molecules.

IL-1 promotes inflammation and the activation of immune cells.

T cells, including cytotoxic T cells (CD8+) and helper T cells (CD4+).

MHC molecules are often viewed from a top-down perspective to understand where the antigen binds.

Polymorphism refers to the existence of multiple alleles or variants of a gene within a population, leading to genetic diversity in MHC molecules.

Cytotoxic T Lymphocyte.

They assist other immune cells by releasing cytokines that enhance the immune response.

Receptors bind to signaling molecules (ligands) and initiate the signal transduction process.

They proliferate and differentiate into effector CTLs capable of killing infected or abnormal cells.

Signal transduction is the process by which a signal is transmitted through a cell as a series of molecular events, typically involving protein phosphorylation, leading to a cellular response.

By the genome.

TH1 stands for T helper type 1 cells.

The primary function of Helper T cell cytokines is to regulate and coordinate the activities of other immune cells.

They present antigens to T cells, thus bridging the innate and adaptive immune responses.

Primary and secondary immune responses.

IgM.

The body’s response to tissue damage or microbial invasion.

The primary immune response occurs when the immune system encounters an antigen for the first time, leading to a slower and less intense response.

Interleukin-12 (IL-12) is crucial for the differentiation of naive T cells into Helper T cells.

It dictates co-receptor expression and is essential for positive selection.

Common features of microorganisms called Pathogen Associated Molecular Patterns (PAMPs).

After successful heavy-chain (BCR) and β-chain rearrangements.

Anti body gen erator, a compound that elicits antibody production.

No, not everything needs the adaptive response.

A condition where the immune system's ability to fight infectious disease is compromised or entirely absent.

Extracellular infection.

From the bloodstream and bones.

Random rearrangement of multiple gene segments.

Gene segment recombination occurs during the early stages of B cell development in the bone marrow.

IL-2 is crucial for the survival and function of regulatory T cells, which help maintain immune tolerance.

More cells bind to the vessel surface and enter the tissue.

Memory T cells provide long-term immunity by remaining in the body and responding more rapidly and effectively if the same antigen is encountered again.

Interferon-alpha (IFN-α) is known for its antiviral properties.

B cells.

Macrophages ingest pathogens and release signals that activate NK cells.

Most effector T cells undergo apoptosis (programmed cell death) after the infection is cleared to prevent excessive immune response.

In the endoplasmic reticulum (ER).

To kill infected or cancerous cells.

In tissues that are in contact with the external environment, such as the skin (Langerhans cells) and the inner lining of the nose, lungs, stomach, and intestines.

Perspiration contains salt which inhibits pathogen growth and antimicrobial substances.

By endocytic vesicles.

IFN-γ helps activate macrophages and assists CD8+ T cells in killing infected cells.

With age, the proportion of naive T cells decreases while the proportion of memory T cells increases.

There are three possible reading frames for a given nucleotide sequence, depending on the starting point.

Heavy-chain (BCR) and β-chain (TCR).

Cytokines produced by CD4 T cells help in the activation, growth, and differentiation of CD8 T cells, enhancing their ability to kill infected cells.

Because it is dry, oily, and salty, making it difficult for most microbes to get past.

The mucociliary escalator of the throat moves mucus up the throat where anything contained in it can be swallowed and destroyed in the stomach.

Accessory proteins take care of signal transduction.

The sequence 'NOWITSNOTTOOHOTFORZOOYOUCANSEESIXOWLFLY' can be read in different frames: 'NOW ITS NOT TOO HOT FOR ZOO YOU CAN SEE SIX OWL FLY', 'N OWI TSN OTT OOH OTF ORZ OOY OUC ANS EES IXO WLF LY', and 'NO WIT SNO TTO OHO TFO RZO OYO UCA NSE ESI XOW LFL Y'.

Macrophages contribute to the immune response by presenting antigens to T cells and secreting cytokines that modulate the activity of other immune cells.

40% to 70% are infected with CMV.

Tdt (Terminal deoxynucleotidyl transferase).

Lymphocytes are either activated or killed.

Antigen presentation is crucial for T cells to recognize and respond to pathogens.

Effector T cells perform functions such as killing infected cells (cytotoxic T cells) or helping other immune cells (helper T cells).

Clonal selection is the process by which specific B and T cells are activated and proliferate in response to recognizing an antigen.

Microorganisms found growing on body surfaces of healthy individuals.

Because they are the key messengers that can present antigens to the adaptive immune response and also phagocytose.

Th1 cells are involved in cell-mediated immunity and help activate macrophages.

T cells.

At the tip of the 'Y'.

NK cells release Interferon-gamma (IFN-γ).

The adaptive response is usually faster and stronger than the first response.

Stimulation of both innate and adaptive responses, cytokine production and release, inflammation, CTL activity, and B cell regulation

There would be no adaptive immune response.

Perforin and granzymes.

At the base of the 'Y'.

It triggers apoptosis in the target cell.

TH1 cells are primarily involved in cell-mediated immunity and help activate macrophages.

No, they lack antigen specificity.

T cells are activated when their TCRs bind to an antigen-MHC complex, along with co-stimulatory signals from antigen-presenting cells.

T cells recognize antigens that have been processed and presented by another cell.

By alternative splicing at the RNA level.

V and J segments.

The macrophage mannose receptor is a C-type lectin that binds sugar residues.

Because they recognize and destroy host cells that lack MHC class I molecules, which is a common occurrence in viral infections.

B cells can recognize a wide variety of antigens, including proteins, polysaccharides, lipids, and nucleic acids.

Monocytes are a type of white blood cell that circulates in the blood.

They are inherited as pairs of α- and β-chain genes from each parent.

The primary types of adaptive immune cells are T cells and B cells.

IL-2 primarily stimulates the growth and differentiation of T cells.

It ensures that each lymphocyte will only express one antigen-specific receptor.

Endogenous antigens.

Dendritic cells, B cells, and macrophages.

Activated T cells differentiate into effector T cells and memory T cells.

Billions.

T cells.

The primary function of the T Cell Receptor (TCR) is to recognize and bind to specific antigens presented by Major Histocompatibility Complex (MHC) molecules on the surface of antigen-presenting cells.

Th1, Th2, Th17, and Treg cells.

Yes, any effector cell can migrate to the site of infection, but there is selective retention.

To defend against intracellular pathogens and cancer cells.

They become single-positive T cells, expressing either CD4 or CD8, and are almost fully mature.

By the T cell receptor (TCR).

Only the heavy chain constant region.

S1P is high in blood and lymph and low in lymph tissue, influencing T cell movement.

Helper T cells are a type of T cell that play an important role in the immune system by releasing cytokines to regulate immune responses.

The immunological synapse allows for the stable interaction and signaling between the T cell receptor (TCR) and the antigen-MHC complex, along with co-stimulatory signals, which are crucial for T cell activation.

Sebum helps keep the skin pliable and lowers skin pH to a level inhibitory to many bacteria.

IgG.

The reading frame determines which amino acids will be encoded by the nucleotides, thus affecting the resulting protein.

Chemotaxis is the directed movement of cells towards higher concentrations of a chemical signal, often seen in immune cell migration towards infection sites.

In some cases, T cell exhaustion can be partially reversed by blocking inhibitory receptors like PD-1 and CTLA-4, which can restore some T cell function.

Microbial invasion or tissue damage.

Helper T cell cytokines, such as IL-4, promote B cell proliferation and differentiation into plasma cells that produce antibodies.

TH1 cells predominantly produce the cytokine IFN-γ (Interferon gamma).

Because it inhibits the growth of pathogens and activates other body defenses.

TH1 is associated with the cell-mediated immune response.

In older individuals, the bulk of T cells are memory T cells.

Cytokines are small proteins that are important in cell signaling, especially in immune responses.

L-selectin and CCR7.

MHC molecules have two chains, typically referred to as chain A and chain B.

Cytokines are signaling molecules that mediate and regulate immunity, inflammation, and hematopoiesis.

They are involved in antigen presentation to the adaptive immune response.

Co-stimulatory signals provided by interactions between CD28 on the CTL and B7 on the antigen-presenting cell.

Antigen.

TNF-α is involved in systemic inflammation and can induce fever and apoptosis.

T Cell Receptors (TCRs) recognize antigens by binding to peptide fragments presented by Major Histocompatibility Complex (MHC) molecules on the surface of antigen-presenting cells.

Helper T cells (Th cells).

T cells, including cytotoxic T cells (CD8+) and helper T cells (CD4+).

It ships proteins processed in the endoplasmic reticulum (ER) to their destination.

Monocytes originate in the bone marrow.

Cytokines are signaling molecules that help regulate and coordinate the immune response.

A reading frame is a way of dividing the sequence of nucleotides in a nucleic acid (DNA or RNA) into a set of consecutive, non-overlapping triplets or codons.

Effector proteins carry out the cellular response to the signal, such as altering gene expression or modifying cellular metabolism.

The first signal is provided by the recognition of an antigen by the lymphocyte receptor.

T cell exhaustion leads to a diminished immune response, making it difficult for the body to effectively combat chronic infections or cancer.

Vaccines work on the principle that the adaptive response becomes faster and stronger with subsequent exposures.

If the antigen is recognized, S1P receptor expression is suppressed for several days.

The two-signal requirement ensures that lymphocytes are only activated in the presence of a genuine threat, preventing inappropriate immune responses.

In the lymph nodes.

GPCRs are a large family of receptors that play a key role in many signal transduction pathways by activating G-proteins.

Heat, pain, redness, swelling.

The first signal is the recognition of the antigen-MHC complex by the T cell receptor (TCR).

Scavenger receptors recognize anionic polymers and acetylated low-density lipoproteins.

It prevents premature binding of peptides to MHC Class II molecules and directs them to the endosomal/lysosomal pathway.

Toll-like receptors bind a variety of membrane or vesicle-associated microbial antigens.

Cytotoxic T-lymphocytes directly kill infected cells by recognizing antigens presented on their surface.

By creating a diverse repertoire of antibodies, V(D)J recombination enables the immune system to recognize and respond to a vast array of pathogens.

To defend against intracellular pathogens and cancer cells.

Each B cell recognizes something completely different from all of the others.

TCR (T Cell Receptor) and BCR (B Cell Receptor).

By recognizing antigens presented by MHC class I molecules and inducing apoptosis in the infected cells.

Effector cells recognize microbial antigens through MHC-associated antigen presentation.

T cell exhaustion is a state of dysfunction that arises in T cells during chronic infections or cancer, characterized by poor effector function, sustained expression of inhibitory receptors, and a transcriptional state distinct from functional effector or memory T cells.

IL-6 stimulates acute phase responses and the production of antibodies.

They present intracellular antigens to cytotoxic T cells, triggering an immune response.

By recognizing antigens presented by MHC class I molecules and inducing apoptosis in the infected cells.

Key components include the T cell receptor (TCR), major histocompatibility complex (MHC) molecules, co-stimulatory molecules, and adhesion molecules.

They assist other immune cells by releasing cytokines that enhance the immune response.

Protein receptors displayed on the surface of the cell.

Cytokines

The second signal is provided by co-stimulatory molecules on antigen-presenting cells.

Cytokines are signaling molecules that help regulate and coordinate the immune response.

The general outcome of signal transduction is a specific cellular response, such as gene expression, cell division, or apoptosis.

Through their T cell receptors (TCRs) which bind to specific antigens presented by MHC molecules.

IgD.

CD5.

To present antigens to helper T cells (CD4+ T cells).

Memory cells enable the immune system to respond more quickly and effectively upon re-exposure to the same antigen.

Three pairs.

At the DNA level.

Adaptive cells are immune cells that are part of the adaptive immune system, primarily including T cells and B cells.

Cytokines bind to surface receptors and regulate cell function.

Helper T Cells assist other white blood cells in immunologic processes, including the activation of B cells to secrete antibodies and macrophages to destroy ingested microbes.

They move towards the site of infection to combat the bacteria.

B and T cells reside in the lymph nodes.

Receptors, ligands, second messengers, and effector proteins.

MHC molecules present peptide fragments to T cells, enabling the immune system to recognize and respond to pathogens.

To act as antigen-presenting cells that initiate and modulate the immune response.

Co-stimulation

Alpha-beta (αβ) TCRs are more common and primarily recognize peptide antigens presented by MHC molecules, while gamma-delta (γδ) TCRs can recognize a broader range of antigens, including non-peptide antigens, and are less dependent on MHC presentation.

Second messengers are intracellular signaling molecules released by the cell in response to exposure to extracellular signaling molecules.

CD4 T cells, also known as helper T cells, assist other cells in the immune response, while CD8 T cells, also known as cytotoxic T cells, directly kill infected or cancerous cells.

IgG, IgA, IgM, IgE, and IgD.

It could take just 2-3 days and even faster the next time.

They have low pH and proteases that break down protein.

If the antigen is not recognized, S1P receptor expression increases, allowing the T cell to leave through the efferent lymph vessel.

Phosphorylation is a common mechanism for activating or deactivating proteins and enzymes in signal transduction pathways.

MHC molecules are always in excess to antigens.

A shift in the reading frame, known as a frameshift mutation, can result in a completely different translation from the original, often leading to nonfunctional proteins.

NK cells kill cells that show signs of being abnormal or infected.

Follicular B cells.

Dilation of blood vessels, leakage of fluid from vessels, and migration of leukocytes and phagocytes.

Skin and mucus.

Three.

By using the invariant chain (Ii) which blocks the peptide-binding groove of MHC Class II molecules in the endoplasmic reticulum.

They typically enter by the lungs, not by direct skin contact.

Resting mature B cells.

The inflammasome is a multiprotein complex in the cytosol that activates inflammatory responses.

It activates and speeds them up.

Between blood and lymph tissue.

Altered gene expression.

Innate and Adaptive.

They are where B and T cells develop.

T cells only recognize proteins.

TH1 cells secrete IFN-γ, which activates macrophages to enhance their microbicidal activity.

Signals of tissue damage recognized by the innate immune response.

T cells, including cytotoxic T cells (CD8+) and helper T cells (CD4+).

Three from each parent, totaling six.

They pick up the slack for cytotoxic T cells by targeting and destroying cells that cytotoxic T cells might miss.

To activate inflammatory responses by processing pro-inflammatory cytokines like IL-1β and IL-18.

Siblings can have different combinations of MHC genes, leading to potential mismatches.

CD28 provides a costimulatory signal necessary for full T cell activation by binding to B7 on the antigen-presenting cell.

Successful T cell activation leads to T cell proliferation, differentiation into effector cells, and the initiation of an adaptive immune response.

Innate Response and Adaptive Response.

It may not pick up and destroy cancer cells.

Leukocytes.

They are important in host defenses.

On mucous membranes and in phagocytes.

To localize and eliminate pathogens and to remove damaged tissue.

B cells produce antibodies that neutralize pathogens and mark them for destruction.

Eta (Η, η)

Omicron (Ο, ο)

On the loops at the tips of the variable region.

They are sites where immune cells encounter antigens and initiate immune responses.

Molecules that bind to receptors on the cell surface or inside the cell.

IL-12 is crucial for the differentiation of naive T cells into TH1 cells.

The external domain binds the ligand.

The contraction phase typically occurs around Day 30.

By elevating the body temperature above the maximum growth temperature of pathogens.

Cytokines provide additional signals that promote T cell proliferation, differentiation, and survival.

Proteins and polysaccharides.

In tears, saliva, blood, and phagocytes.

Neutrophils.

The immune system treats the transplant as foreign if it is not identical.

To carry oxygen in the blood.

Th1 and Th2 cells

Recognition by tissue macrophages and complement.

Dead neutrophils.

Mechanisms like pattern recognition receptors (PRRs) that detect pathogen-associated molecular patterns (PAMPs).

The process by which phagocytes engulf and digest pathogens and debris.

NK cells kill virus-infected cells and tumor cells by releasing cytotoxic granules.

Cytokines are signaling molecules that mediate and regulate immunity, inflammation, and hematopoiesis.

They produce a specific molecule and the same set of effector proteins.

T cells help in killing infected host cells, activating other immune cells, and regulating immune responses.

CD8+ T cells induce apoptosis through the release of perforin and granzymes or by engaging death receptors on the target cell surface.

Iota (Ι, ι)

Tau (Τ, τ)

They are important in the process of antibody-dependent cellular toxicity, enabling the killing of host cells with foreign protein in the membrane.

TH1 responses typically target intracellular pathogens such as viruses and certain bacteria.

In the peritoneal and pleural cavity fluid.

Increased blood flow to the area.

V-J rearrangement.

It can be damaging and form an abscess.

Foreignness, size, and complexity of the compound.

By alternative splicing at the RNA level.

The invariant chain is degraded, allowing antigenic peptides to bind to the MHC Class II molecules.

L-selectin and chemokine receptor CCR7.

Peroxidase breaks down hydrogen peroxide to produce reactive oxygen.

Polymorphonuclear neutrophilic leukocytes (PMNs).

More epitopes generally lead to a better immune response.

Physical barriers such as skin and mucous membranes that prevent pathogen entry.

A naïve immune cell is one that has not yet encountered its specific antigen.

An effector immune cell is one that has been activated and is actively responding to an antigen.

No, the innate immune response does not have memory.

NK cells are more likely to kill cells with low or absent MHC class I molecules, as the inhibitory signals are reduced.

Three different ways.

Lectin pathway, classical pathway, and alternative pathway.

Th2 cells produce cytokines such as IL-4 and IL-5 that stimulate B cell differentiation and antibody production, particularly IgE, and are involved in responses to extracellular parasites.

Sigma (Σ, σ/ς)

Mannose-binding lectin is free in plasma, part of the collectin family, and binds sugar residues.

Host cells with no MHC class I surface molecules.

Ubiquitous self and foreign antigens.

The second signal is the costimulatory signal provided by the interaction between CD28 on the T cell and B7 on the antigen-presenting cell (APC).

Large granular lymphocytes.

By recognizing antigens presented by MHC class I molecules and inducing apoptosis in the infected cells.