Major Histocompatibility Complex Overview

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Questions and Answers

What is the Major Histocompatibility complex?

It’s a locus of genes responsible for producing molecules required for antigen presentation and rejection of the tissue grafts

Which of the following is NOT a general characteristic of the Major Histocompatibility Complex (MHC) in mammals?

MHC genes are highly polymorphic

MHC genes are co-dominantly expressed

MHC molecules are expressed exclusively on red blood cells (correct)

MHC molecules are crucial for graft rejection and immune recognition

What is the primary role of MHC molecules in the immune system?

Binding free pathogens for destruction

Presenting antigenic peptides to T cells (correct)

Inducing direct apoptosis in infected cells

Suppressing cytokine production in response to infection

Which type of cells predominantly express MHC class II molecules?

Dendritic cells, macrophages, and B cells Signup and view all the answers

Which of the following components is essential for the stable expression of MHC class 1 molecules on the cell surface?

alpha chain, Beta2 microglobulin, and a peptide Signup and view all the answers

The antigen binding groove of MHC II molecules is formed by which structural domains?

alpha 1 and beta 1 domains Signup and view all the answers

How might specific MHC alleles contribute to the development of autoimmune diseases in animals?

By failing to present a critical antigen and mount a protective immune response Signup and view all the answers

The _ responsible for survival or rejection of a graft were called tissue or ____

The genes responsible for survival or rejection of a graft were called tissue or histo-compatibility genes Signup and view all the answers

All animals have histocompatibility molecules

True Signup and view all the answers

How many classes of MHC molecules exist?

3 Signup and view all the answers

Which of the following is a defining feature of MHC class 1 molecules?

They are expressed on all nucleated cells and present on antigens to CD8+ T cells Signup and view all the answers

Which of the following accurately describes the role of MHC class II molecules?

They present longer peptides (usually >13 amino acids) to CD4+ helper T cells Signup and view all the answers

Which of the following best defines MHC class III molecules?

They encode proteins involved in the regulation of the innate immune response, such as complement proteins Signup and view all the answers

What is a key difference between MHC Class Ia and Class Id molecules?

MHC Class Id molecules are located outside the MHC region on a different chromosome Signup and view all the answers

All numbers of Class 1a loci are functional.

False Signup and view all the answers

MHC molecules were originally fond on what type of cells?

They were originally found on white blood cells. Signup and view all the answers

How many different genes do you express for MHC1?

6 genes, A, B & C Signup and view all the answers

Why does each individual possess six different MHC class I molecules?

The MHC genes are codominantly expressed, with three genes (A, B & C) inherited from each parent Signup and view all the answers

Class 1 MHC molecules are highly polymorphic, meaning

MHC molecules exhibit a wide variety of peptide binding specificities Signup and view all the answers

In terms of peptide length, MHC class 1 molecules accommodate peptides that are:

8-10 aa long Signup and view all the answers

Which of the following does NOT encode proteins involved in antigen presentation?

MHC 3 Signup and view all the answers

What characteristic is specific to MHC class 2 molecules?

They consist of alpha and beta chains Signup and view all the answers

A set of MHC alleles present on a chromosome is called a _______

Haplotype Signup and view all the answers

MHC class 1 and MCH class 2 are the main antigen presenting molecules

True Signup and view all the answers

MCH class 1 molecules are expressed on all nucleated cells except …. (Hint: 3)

They aren’t usually found on red blood cells, gametes, neurons or trophoblast Signup and view all the answers

MCH III regulates the adaptive immune response and not the innate immune response

False Signup and view all the answers

Each MHC 1 molecules has an (intracellular/extracellular) domain which makes up the ______________

Each MHC 1 molecules has an extracellular domain which makes up the antigen binding groove Signup and view all the answers

Which MHC class 1 molecule REGION binds to CD8 co receptors?

Alpha 3 Signup and view all the answers

Which of the following best describes peptide-TCR?

A TCR has fine specificity and can bind only one specific peptide presented by an MHC molecule Signup and view all the answers

What cytokines increase the expression of MHC class 1 molecules?

All the above Signup and view all the answers

Which cytokine increases expression of MHC class 2 molecules on dendritic cells and macrophages?

IFN gamma Signup and view all the answers

What are the potential outcomes of antigen presentation through MHC II, respectively?

These are expressed on APC’s (e.g. dendritic cells, macrophages and B cells) and present exogenous (extracellular) antigens to CD4+ helper T cells. The outcome is the activation of helper T cells, which in turn secrete cytokines that help activate other immune cells like B cells (to produce antibodies) and macrophages (to enhance phagocytosis). This contributes to a broader immune response, particularly against extracellular pathogens. Signup and view all the answers

What is the primary benefit of conducting MHC typing for organ transplantation?

To increase the compatibility between donor and recipient Signup and view all the answers

How can MHC typing contribute to the study of autoimmune diseases?

By linking specific MHC alleles to disease risks Signup and view all the answers

In the context of disease susceptibility, what role does MHC typing serve?

Determining the genetic predisposition to certain diseases Signup and view all the answers

What influence do MHC molecules have on vaccination responses?

They affect how effectively an individual presents antigens to T cells Signup and view all the answers

What is a common application of MHC typing in veterinary medicine?

Identifying genetic predispositions to diseases Signup and view all the answers

Study Notes

MHC Molecules in Diagnostics

Transplant Compatibility: MHC typing is essential for organ and tissue transplantation. Matching MHC alleles between donor and recipient reduces graft rejection and enhances graft survival.
Disease Susceptibility and Resistance: MHC typing can identify individuals genetically predisposed to certain diseases. For example, specific MHC alleles are associated with susceptibility or resistance to autoimmune disorders and infections.
Autoimmune Disease Research: MHC typing is valuable in understanding autoimmune diseases. Certain MHC alleles are linked to autoimmune conditions, such as ankylosing spondylitis, where HLA-B27 expression increases disease risk.
Vaccination and Immune Response: MHC typing can predict vaccine effectiveness. MHC molecules present antigens, and certain alleles influence an individual's response to specific vaccines.

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Description

This quiz explores the Major Histocompatibility Complex (MHC), a crucial part of the immune system that plays a significant role in the body's ability to recognize foreign molecules. Understanding MHC is essential for fields like immunology and transplantation biology. Test your knowledge on its functions and importance.