What are the proteins encoded by MHC Class II genes?
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Proteins that present exogenous antigens to CD4+ T cells.
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What are the proteins encoded by MHC Class II genes?
Proteins that present exogenous antigens to CD4+ T cells.
What is required for T-cells to be activated?
Processed and presented antigens.
What are superantigens?
Molecules that can activate T-cells without the need for processed antigens.
What are HLA-DR alleles?
Different alleles that encode proteins in the immune system.
What type of response is elicited by MHC I?
Cytotoxic response.
What is the primary reason for differences among individuals in a population?
Selection advantage for the population.
Is there an answer to differences at the individual level?
No, there’s no answer at the individual level.
What is a key feature of several viruses and tumors regarding lymph nodes?
They do not appear in lymph nodes.
What does an individual produce due to MHC polygeny and polymorphism?
A number of different MHC molecules.
What type of antigen presentation is performed by dendritic cells?
Classical presentation.
What does the result 'A single cell can display a large array of MHCs' imply?
It indicates the diversity of MHC molecules on a single cell.
What is the function of MHC II molecules?
To present exogenous antigens to CD4+ T cells.
What are the proteins encoded by MHC Class I genes?
Proteins that present endogenous antigens to CD8+ T cells.
What types of antigens can dendritic cells present to T-cells?
Both proteins and lipids.
What is the effect of the combination of polymorphism and polygeny on MHC molecules?
It increases the diversity of MHC molecules within an individual and in the population.
What is cross-presentation?
A process where dendritic cells present extracellular antigens on MHC class I molecules to CD8+ T-cells.
What is lipid antigen presentation?
The process of presenting lipid antigens via CD1 molecules to T-cells.
What is the significance of HLA - A3 and HLA - A1?
They are specific types of Human Leukocyte Antigens.
What is the role of MHC in antigen presentation?
MHC molecules bind to antigens and present them to T-cells for immune recognition.
What is cross-presentation?
The ability of certain antigen-presenting cells to present exogenous antigens via the endogenous pathway.
What is the solution for presenting exogenous antigens as endogenous?
Cross-presentation by dendritic cells.
What are superantigens?
A class of antigens that can activate a large number of T-cells non-specifically.
In a codominant scenario, how are the alleles represented?
Both alleles are expressed simultaneously, such as BB.
What is the role of phagocytes in relation to MHC?
Phagocytes present antigens via MHC molecules.
What do superantigens force in terms of antigen presentation?
Incorrect antigen presentation by MHC-peptide complex independent mechanisms.
What are superantigens?
A class of antigens that can activate a large number of T-cells non-specifically.
What are exogenous antigens?
Antigens that originate from outside the cell.
What are special forms of antigen presentation?
Mechanisms that allow antigens to be presented to T-cells in unique ways.
What is the primary function of MHC molecules?
To present antigens to T-cells.
How does polymorphism contribute to MHC diversity?
Polymorphism allows for a wide variety of MHC molecules, enhancing the immune response.
What is an example of a superantigen?
Staphylococcal enterotoxin.
Are only protein-derived antigens presented by dendritic cells?
No, lipids are also presented.
How are viral peptides presented to elicit a cytotoxic response?
They must be presented as endogenous antigens.
What are the characteristics of MHC I and MHC II loci?
They are closely linked, polygenic, polymorphic on a population level, and co-dominantly inherited.
Name three types of HLA Class I molecules.
HLA-A, HLA-B, HLA-C.
What does HLA stand for?
Human Leukocyte Antigens.
What do MHC polygeny and polymorphism result in?
Several different genes with similar functions.
What type of cells express MHC Class II?
Professional antigen presenting cells (dendritic cells, macrophages, and B lymphocytes).
What is the result of massive production of cytokines?
Systemic toxicity.
Why is MHC diversity important for the immune system?
It enables the recognition of a wide range of pathogens.
What is the role of the crossbridge formed by superantigens?
It connects the TCR β chain and MHC molecules without processing.
What is cross-presentation?
The process by which dendritic cells present extracellular antigens on MHC Class I molecules.
How many different MHC I molecules can be expressed in one individual?
Maximum 6 different MHC I molecules.
How do viruses affect classical antigen presentation?
Viruses often inhibit classical presentation.
What does codominance mean in genetics?
Both alleles of the gene are expressed.
What is TSST-1?
Toxic shock syndrome toxin-1 produced by Staphylococcus aureus.
What does polymorphic mean in genetics?
Each locus has many different alleles.
Which cells express MHC Class I?
All nucleated cells.
What is dissortative mating?
A mating strategy that promotes genetic diversity by encouraging mating between individuals with different genotypes.
What do MHC genes encode?
Cell surface proteins.
What does HLA stand for?
Human Leukocyte Antigens.
What is the function of MHC I molecules?
To present endogenous antigens to CD8+ T cells.
What is the significance of lipid antigen presentation via CD1?
CD1 molecules present lipid antigens to T-cells, expanding the range of antigens recognized by the immune system.
What is the endogenous pathway?
A process by which antigens produced within the cell are presented on MHC molecules.
What role do individual MHC allele polymorphisms play in mating preferences?
They affect odour and mating preferences.
On which chromosome are the MHC loci located?
Human chromosome 6.
What regions are included in the MHC gene region on chromosome 6?
MHC I, MHC II, and MHC III gene regions.
What are some components found in the MHC III gene region?
C4b, Factor B, C4a, C2, and complement C3 convertases.
Name three types of HLA Class II molecules.
HLA-DP, HLA-DQ, HLA-DR.
How can MHC expression influence disease susceptibility?
Certain MHC types are associated with increased risk for specific diseases.
Do dendritic cells present exogenic antigen only to CD4+ helper cells?
No, dendritic cells also present exogenic antigen to CD8+ cytotoxic T cells.
What do individual MHC allele polymorphisms predict?
Resistance and susceptibility to infectious and autoimmune diseases.
How do individual MHC allele polymorphisms affect tissue transplants?
They influence compatibility of tissue transplants.
From where must viral peptides be taken up to elicit a response?
From the extracellular space as exogenous antigens.
What is cross-presentation required for?
To generate cytotoxic T cell-based immunity against some viral and tumor antigens.
How does the structure of CD1 compare to MHC I?
CD1 structure is similar to that of MHC I.
What are the characteristics of the CD1 groove?
It is larger, deeper, and much more hydrophobic than MHC I.
What is exposed to the TCR in CD1-mediated antigen presentation?
More hydrophilic portions of the ligand.
What are HLA - DR2 and HLA - DR4 examples of?
They are types of MHC II molecules.
Why might dissortative mating be considered an adaptive strategy?
To maximize allele supertype diversity.
What does maximizing heterozygosity of allele supertypes refer to?
Focusing on the genetic diversity of groups of alleles rather than individual alleles.
What is the difference between heterozygosity of allele supertypes and individual alleles?
Heterozygosity of allele supertypes considers combinations of alleles, while individual alleles focus on single genetic variations.
What type of antigens does CD1 mediate the presentation of?
Amphipathic lipid antigens.
What does MHC stand for?
Major Histocompatibility Complex.
What type of presentation involves lipid antigens?
Lipid presentation.
Is there a relationship between disease susceptibility and MHC molecule expression?
Yes, there is a relationship.
What role do dendritic cells play in antigen presentation?
They capture, process, and present antigens to T-cells, initiating immune responses.
How many different MHC II molecules can be expressed in one individual?
Maximum 6 different MHC II molecules.
Which cell type has a crucial role in antigen presentation?
Dendritic cell.
What are the two main groups of MHC molecules?
MHC I group and MHC II group.
What are HLA types?
Human Leukocyte Antigens, which are specific MHC molecules in humans.
What is cross-presentation?
A process by which dendritic cells present antigens from extracellular sources on MHC class I molecules.
