30 Questions
What is the primary reason for the existence of multiple alleles in the MHC genes?
To allow the population to deal with the diversity of microbes
How are MHC genes expressed?
Codominantly
What is the main function of MHC molecules?
To present peptides from microbial proteins to T cells
Which type of cells primarily express class II molecules?
Dendritic cells and macrophages
What is the effect of interferon-γ on the expression of class II molecules?
It induces the expression of class II molecules on other cell types
What is the physiologic significance of the different expression patterns of class I and class II molecules?
It is described later in the text
What is the main function of the products of genes such as DM, proteasome components, and TAP?
Antigen processing
What is the main difference between Class I and Class II MHC molecules?
Their subunit composition
What is the name of the protein associated with the α chain in Class I MHC molecules?
β2-microglobulin
What is the typical length of peptides bound by the peptide-binding cleft of Class I MHC molecules?
8-9 amino acids
What type of proteins are Class I and Class II MHC molecules?
Membrane proteins
What is the function of the α1 and α2 domains of the α chain in Class I MHC molecules?
To form a peptide-binding cleft
What is the primary function of dendritic cells in the process of antigen presentation?
To break down and present antigens to T cells
What is the term applied to CD8+ T cells recognizing class I MHC-associated antigens?
Cross-priming
What is ensured by the restriction of T cell recognition to MHC-associated peptides?
T cells see and respond only to cell-associated antigens
Why can MHC molecules be loaded with peptides only inside cells?
Because intracellular and ingested antigens are present inside cells
What type of T cells recognize class II MHC-associated antigens from the microbe?
CD4+ T cells
What is the primary location of antigen processing and presentation in the context of MHC molecules?
Inside the antigen-presenting cells
What is the role of CD4+ helper T cells in the immune response?
To stimulate the production of antibodies
Which cells are responsible for eliminating extracellular microbes?
Macrophages
What is the role of B lymphocytes in the immune response?
To ingest protein antigens of microbes and present them to CD4+ helper T cells
Which cells are effective against intracellular viruses and other pathogens that can survive and replicate in the cytoplasm of host cells?
CD8+ CTLs
What is the result of protein antigens of microbes entering the class I MHC pathway of antigen processing?
Recognition by CD8+ cytotoxic T lymphocytes
Which cells are responsible for ingesting protein antigens of microbes?
B lymphocytes and macrophages
What is a possible outcome when a protein antigen is presented to an individual?
Only a few peptides from the antigen can bind to MHC molecules
What type of T cells recognize class I MHC-peptide complexes?
CD8+ T cells
What strategy do viruses use to evade the adaptive immune system?
Inhibiting the class I MHC pathway
What is the main function of antigen-presenting cells (APCs)?
To ingest and process antigens
What is the final step in the class II MHC pathway?
Transport of peptide-MHC complexes to the cell surface
What is the purpose of the TAP protein in the class I MHC pathway?
To transport peptides into the ER
Learn about the structure and function of Class I and Class II genes in the Major Histocompatibility Complex (MHC), including their roles in antigen processing and immune response. Understand the differences between Class I and Class II genes and their respective functions.
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