What do IL-1 and IL-6 induce?
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Acute-phase responses.
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What do IL-1 and IL-6 induce?
Acute-phase responses.
How do pathogens enter the body?
Through mucosal surfaces or breaches in the skin.
What is the role of TNF-α?
Induces acute phase responses.
What are the two main types of cytokines mentioned?
Pro-inflammatory and anti-inflammatory cytokines.
What type of cells detect pathogens in the innate immune response?
Resident phagocytic cells.
What does GM-CSF stimulate?
Hematopoiesis.
Name three pro-inflammatory cytokines.
IL-1, IL-6, TNFα (Tumor Necrosis Factor Alpha).
What are the basic roles of the immune system?
To protect the body from pathogens and maintain homeostasis.
What do phagocytic cells release to recruit other immune cells?
Antimicrobial compounds and cytokines.
Which cytokines are involved in the adaptive immune response?
IL-12 and IL-18.
What is the primary distinction between skin and mucosal barriers?
Skin barriers are external, while mucosal barriers are found in respiratory, gastrointestinal, and genitourinary tracts.
What distinguishes innate immunity from adaptive immunity?
Innate immunity is non-specific and immediate, while adaptive immunity is specific and develops over time.
Name two anti-inflammatory cytokines.
IL-10 and TGFβ (Transforming Growth Factor Beta).
Where does adaptive immunity get initiated?
In secondary lymphoid structures, such as lymph nodes.
What is the function of IL-10?
Regulation of immune response.
What are common features of skin and mucosal barriers?
They are populated by commensal organisms, contain innate and adaptive immune cells, and include mechanical and chemical barriers.
What are the portals of entry for pathogens into the body?
Through breaches in the skin or mucosal surfaces.
What are cytokines and who produces them?
Cytokines are chemical mediators produced by T cells, innate lymphoid cells, and mononuclear phagocytes.
What are the primary and secondary organs of the immune system?
Primary organs include the bone marrow and thymus; secondary organs include lymph nodes and spleen.
What is the significance of balancing pro- and anti-inflammatory cytokines?
Certain inflammatory diseases present with characteristic cytokine profiles, and balancing them is crucial for treatment.
What is the role of cytokines in the immune response?
Cytokines can produce similar effects and can stimulate the production of additional cytokines, creating a cascade effect.
What happens to B and T cells after they are activated?
They migrate out of the lymph node and join the bloodstream.
What are Type 1 interferons?
IFN α and IFN β, which mediate the early innate immune response to viral infections.
What specialized lymphoid tissues are associated with mucosal barriers?
Peyer patches in the small intestine and isolated lymphoid follicles.
What is the total surface area of epithelial barriers exposed to the environment?
Over 400 square meters.
What is the function of cytokines in the immune response?
They bind to microbes to enhance phagocytosis and promote inflammatory responses.
What is the significance of white blood cells (WBC)?
WBCs are crucial for immune response, including fighting infections and regulating inflammation.
What is antagonism in the context of cytokines?
Antagonism refers to one cytokine counteracting or inhibiting the actions of another cytokine.
How can cytokine-related therapies be beneficial?
They offer promise for treating viral infections, immunodeficiencies, autoimmune diseases, some cancers, and transplant rejection.
What is the role of long-term memory B and T cells?
They take up residence in various locations in the body.
How do Type 1 interferons interfere with viral replication?
By inhibiting protein synthesis, degrading viral RNA, and inhibiting viral gene expression and assembly.
How do commensal organisms in the body help protect against pathogens?
They compete effectively against many potential pathogens.
What are some physical barriers provided by epithelial tissues?
Tight junctions, keratin, and mucus assisted by cilia and peristalsis.
What are examples of endogenous inflammatory mediators?
Complements, cytokines, and chemokines made by specific cells.
What are the phases of the specific acquired immune response?
The phases include recognition, activation, and effector phases.
What are Pathogen-Associated Molecular Patterns (PAMPs)?
Molecular structures produced by microbial pathogens essential for their survival.
What is the role of C3b in the complement system?
C3b attaches to the surface of pathogens, tagging them for destruction and enhancing phagocytosis.
What initiates the acute phase response after an injury?
The activation of innate immune cells by microbes leads to the release of pro-inflammatory cytokines.
What percentage of total leukocytes do eosinophils represent?
1-3%.
What is the primary function of dendritic cells?
To function as antigen presenting cells and link the innate and adaptive immune responses.
What increases the susceptibility of infected cells to cytotoxic T lymphocytes?
Type I interferon.
What happens when normal bacterial flora are disturbed by antibiotics?
Susceptibility to opportunistic infections, such as Candida and Clostridium, may increase.
What are defensins and where are they produced?
Antimicrobial chemicals produced by epithelial cells of mucosal surfaces and granule-containing leukocytes.
What are acute phase proteins?
Proteins produced as a systemic response to injury.
What are Damage-Associated Molecular Patterns (DAMPs)?
Endogenous molecules produced by or released from damaged or dying cells.
What is the Membrane Attack Complex (MAC)?
The end product of the complement cascade that creates pores in target pathogens' cell membranes.
Which pro-inflammatory cytokines are released during the acute phase response?
IL-1, IL-6, and TNF-α (Tumor Necrosis Factor Alpha).
How do immune cells recognize pathogens?
Through pattern recognition receptors (PRRs) that detect pathogen-associated molecular patterns (PAMPs).
What is a key characteristic of eosinophils?
They have pink-staining cytoplasmic granules.
How do dendritic cells capture microbial antigens?
They capture microbial antigens that enter the skin, gastrointestinal tract, and respiratory tract.
What cells produce Type 1 interferons?
Plasmacytoid dendritic cells and virus-infected cells.
What role does mucus play in the respiratory tract?
It traps microbial particles, which are then removed by cilia movement, coughing, or sneezing.
What role do cathelicidins play in the immune response?
They are produced by neutrophils and barrier epithelial cells to provide direct toxicity to microorganisms.
What are Pattern Recognition Receptors (PRRs)?
Receptors used by innate immunity to recognize PAMPs and DAMPs.
What is the complement system composed of?
Over 50 serum glycoproteins that cooperate with both the innate and adaptive immune systems.
What are the three pathways of complement activation?
Classical, alternative, and lectin pathways.
What are acute phase proteins?
Proteins whose concentration is increased or decreased by at least 25% following injury.
What are the roles of different leukocytes in the immune response?
Leukocytes are involved in phagocytosis, inflammation, and adaptive immune responses.
What receptors do eosinophils have?
Fc receptors, TLR, receptors for IL-5 and IL-3.
What happens to dendritic cells after they phagocytose antigens?
They mature and transport the antigens to regional lymph nodes.
What are some mechanical factors that provide protection in the body?
Washing action of tears, saliva, and urine, along with secreted body fluids that have bactericidal components.
What happens as soon as foreign bodies breach the barrier?
Immune cells are able to recognize them right away.
What is the function of intraepithelial T-lymphocytes?
They recognize and respond to common microbial structures.
Which cells express the widest variety of PRRs?
Phagocytes and dendritic cells.
What are the three pathways to activate the complement system?
Classical Pathway, Mannose Binding Lectin Pathway, and Alternative Pathway.
What are the main functions of complement proteins?
Direct microbial killing, opsonization, activation of inflammatory response, cellular activation for microbial killing, and clearing immune complexes.
How do the classical and alternative pathways differ in activation?
The classical pathway is initiated by antigen-antibody complexes, while the alternative pathway is activated by direct contact with pathogens.
What is C-reactive protein (CRP) used for?
CRP is a non-specific marker of inflammation used to monitor or detect significant inflammation in acute conditions.
What is the function of antigen-presenting cells (APCs)?
APCs process and present antigens to T cells, initiating the adaptive immune response.
What percentage of total leukocytes do basophils represent?
<1%.
What type of cells are NK cells?
They are innate lymphoid cells that do not express antigen-specific receptors.
What types of cells arise from myeloid progenitors?
Granulocytes (neutrophils, eosinophils, basophils, mast cells), monocytes, and macrophages.
How quickly is innate immunity stimulated after foreign body invasion?
Within 0-4 hours.
What is Mucosal Associated Lymphoid Tissue (MALT)?
It is associated with mucosal tissues and initiates immune responses to specific antigens.
What is the role of C3b in the complement system?
C3b functions as an opsonin, coating organisms for eventual killing by phagocytes.
What is the function of Toll-like receptors (TLRs)?
They recognize PAMPs and activate signal transduction pathways.
How is the classical pathway of the complement system triggered?
By immune complexes that recognize preformed IgM or IgG Ag-Ab complexes.
What physiological changes occur due to the acute phase response?
Leukocytosis, increased synthesis of ACTH and hydrocortisone, induction of fever, and initiation of adaptive immune response.
What mechanisms do cytokines use to exert their effects?
Pleiotropy, synergy, and redundancy.
What is the role of cytokines in the immune system?
Cytokines are signaling molecules that mediate and regulate immunity, inflammation, and hematopoiesis.
What is a key characteristic of basophils?
They have blue-staining cytoplasmic granules.
What is the primary function of neutrophils?
They are the principal cell type in acute inflammatory reactions and function as phagocytic cells.
What is the role of NK cells in the immune response?
They kill tumor cells and infected cells that lack MHC Class I expression.
What type of cells are Langerhans cells and what is their role?
They are dendritic cells involved in T-helper mediated immunity against skin pathogens.
When does adaptive immunity develop if innate immunity cannot control foreign bodies?
After more than 96 hours.
How do C3a and C5a contribute to the inflammatory response?
C3a acts as a chemoattractant for eosinophils, while C5a acts as a chemotactic agent for neutrophils and monocytes.
What protects healthy cells from inadvertent activation of the alternative pathway?
CD55 (Decay Accelerating Factor) and CD59 (Membrane Inhibitor of Reactive Lysis).
What is the final product of the classical pathway?
C5 convertase in the form C4b2a3b.
How does fever occur during the acute phase response?
Fever is caused by the hypothalamus responding to elevated levels of acute phase proteins, influenced by TNF and IL-1.
What is the significance of understanding the differentiation and maturation of WBCs?
It helps in diagnosing and treating various immune-related conditions and diseases.
What is leukocytosis?
A transient increase in the number of circulating white blood cells during acute infection.
What is the role of mast cells?
They release inflammatory mediators and are involved in allergic reactions.
What do dendritic cells express that helps activate naive T cells?
High levels of peptide-MHC complexes, host stimulators, and cytokines.
What is the role of dermal dendritic cells?
They initiate protective responses against viruses involving helper T-cells and cytotoxic T-cells.
Where do all cellular elements of the blood derive from?
Pluripotent hematopoietic stem cells in the bone marrow.
What triggers the Mannose Binding Lectin pathway?
Complexes between bacterial mannose residues and plasma protein lectin.
What is the significance of serum amyloid A during inflammation?
Serum amyloid A can rise a thousand-fold during inflammation and helps recruit immune cells to the inflammation site.
What are anaphylatoxins and their effects?
C3a and C5a are anaphylatoxins that trigger degradation of mast cells and basophils, releasing histamine and enhancing vascular permeability.
What do basophils and mast cells have in common?
They both express high-affinity plasma membrane receptors for IgE.
What is the process of neutrophil extracellular trap (NET) formation?
It involves neutrophil activation, granule lysis, and the release of DNA and granule contents to immobilize and kill extracellular microbes.
What type of cells arise from the lymphoid lineage?
T cells and B cells.
What is the approximate number of leukocytes in one microliter of whole blood?
About 7,000 leukocytes.
What types of immune cells are present in the skin immune system?
NK cells, macrophages, and mast cells.
What is unique about the alternative pathway?
It is triggered by contact with viruses, bacteria, fungi, and tumor cells, independent of Ag-Ab interactions.
What is leukocytosis and how is it affected by the acute phase response?
Leukocytosis is the increased release of neutrophils and monocytes from the bone marrow, promoted by cytokines.
What triggers the activation of the complement system?
Activation occurs when C3 levels in the serum become low.
What is the lifespan of eosinophils?
5-12 days.
What is the function of eosinophils?
They are granulocytic cells important in the body's defense against parasitic organisms.
What are some key proteins contained in neutrophil granules?
Lysozyme, collagenase, elastase, myeloperoxidase, defensins, and cathelicidin.
What two types of committed stem cells do pluripotent cells divide into?
Myeloid progenitor and lymphoid progenitor.
What is the role of C3b in the complement pathways?
C3b serves as the binding site for C5 serum protein, which is split into C5a and C5b.
What are cytokines?
Cytokines are structurally diverse polypeptides that function as messenger molecules in the immune system.
What are the two types of monocytes?
Inflammatory monocytes and patrolling monocytes.
What type of cells are microglial cells?
Phagocytic cells of the central nervous system.
What lineage does the common myeloid progenitor give rise to?
The myeloid lineage, including erythrocytes, megakaryocytes, and leukocytes.
What are the different types of cytokines?
Lymphokines, monokines, chemokines, interleukines, and interferons.
What is the membrane attack complex (MAC)?
A structure formed by C5b and complementary proteins that can insert into the membrane of target cells, leading to cell lysis.
What is the primary function of macrophages?
They are expert phagocytes and professional antigen-presenting cells.
What do mast cells and basophils release?
Histamine and various pharmacologically active substances.
What are granulocytes?
Basophils, eosinophils, and neutrophils, characterized by their cytoplasmic granules.
How do cytokines typically act on cells?
Cytokines bind with high affinity to receptors and utilize the JAK-STAT signaling pathway.
What activates macrophages?
Recognizing microbial molecules and host molecules produced in response to infections or injury.
What is the common progenitor for T and B cells?
Hematopoietic stem cells (HSCs).
What do monocytes differentiate into after entering tissues?
Phagocytic macrophages or dendritic cells.
What roles do cytokines play in the immune system?
They communicate signals, instruct cells to proliferate, differentiate, secrete additional cytokines, migrate, or die.
What are fixed macrophages?
Tissue-resident macrophages that usually arise early in life from embryonic cells.
What are innate lymphoid cells (ILCs) characterized by?
They do not express antigen-specific receptors.
What stimulates the production of lymphoid cells?
Interleukins and other cytokines such as stem cell factors, GCSF, and GM-CSF.
What is the role of the Interleukin 1 family of cytokines?
They promote inflammation.
What are some functions of macrophages?
Inflammation, enhanced adaptive immunity, killing of microbes, tissue repair, and homeostasis.
What is the role of complement proteins?
They are soluble components present in plasma, primarily made by the liver.
Which cells are classified as myeloid?
Dendritic cells (conventional), neutrophils, basophils, and macrophages.
What are the primary functions of the immune system?
Recognition and elimination of pathogens, and development of immune cells.
What receptors are present on macrophage membranes?
PRRs, including TLR, cytokine receptors, and complement receptors.
Which cells belong to innate immunity?
Dendritic cells, neutrophils, NK cells, basophils, macrophages, and ILCs.
What is the difference between T cells and B cells?
T cells are primarily involved in cell-mediated immunity, while B cells are responsible for humoral immunity and antibody production.
Which cells belong to acquired immunity?
T cells and B cells.
What is the cell-mediated immune response?
It involves T lymphocytes that directly attack infected or cancerous cells.
What is antigen presentation?
The process by which antigen-presenting cells display antigens on their surface to T cells.
How do antigen presenting cells function?
They capture, process, and present antigens to T cells, activating them.
What is the difference in antigen processing by class I MHC vs. class II MHC?
Class I MHC presents endogenous antigens to CD8+ T cells, while class II MHC presents exogenous antigens to CD4+ T cells.
What signals are required for T cell activation and differentiation?
T cell activation requires recognition of the antigen-MHC complex and co-stimulatory signals from antigen presenting cells.
What are the roles of different types of T cells?
CD4+ T helper cells assist other immune cells, while CD8+ cytotoxic T cells kill infected or cancerous cells.
What are the phases of the humoral immune response?
The phases include activation of B cells, clonal expansion, and differentiation into plasma cells that produce antibodies.
How can B cells be activated?
B cells can be activated through T-dependent and T-independent pathways.
What is the cellular basis of antibody production?
B cells differentiate into plasma cells that produce antibodies in response to antigens.
What are the different types of antibodies?
The main types include IgG, IgA, IgM, IgE, and IgD, each with distinct functions.
What are the functions of different immunoglobulin classes?
IgG provides long-term immunity, IgA protects mucosal surfaces, IgM is the first antibody produced, IgE is involved in allergic reactions, and IgD is a receptor on B cells.
What is the difference between primary and secondary immune responses?
The primary response is slower and occurs upon first exposure to an antigen, while the secondary response is faster and stronger due to memory cells.
What are the roles of the immune system in hypersensitivity reactions?
The immune system can overreact to harmless substances, leading to allergic reactions.
How does the immune system respond to transplantation?
The immune system may recognize transplanted tissues as foreign and mount a response against them.
What is the role of the immune system in autoimmune diseases?
The immune system mistakenly attacks the body's own tissues, leading to autoimmune conditions.
How does immunodeficiency affect the immune system?
Immunodeficiency results in a weakened immune response, increasing susceptibility to infections.
What is the role of the immune system in chronic inflammation?
The immune system can cause prolonged inflammation, which may lead to tissue damage and disease.
What is immunity?
Immunity is the ability to protect oneself from disease.
What is immunology?
Immunology is the study of cells, organs, and molecules responsible for immunity and their interactions.
What are the levels of defense in the immune system?
Levels of defense include physical barriers, innate immune response, and adaptive immune response.
What is the difference between innate and adaptive immune responses?
Innate immunity is rapid and nonspecific, while adaptive immunity is slow, specific, and has memory.
