Major Histocompatibility Complex

Question 1

What does MHC represent?

Answer 1

Major histocompatibility complex

Question 2

What is the major histocompatibility complex?

Answer 2

Tightly-linked cluster of genes, encoding a number of different protein molecules

Question 3

True or false: the MHC plays a major role in transplantation acceptance/rejection.

Answer 3

True

Question 4

MHC is also known as ____ in humans.

Answer 4

HLA

Question 5

The MHC is a collection of 40-50 genes, located on Chromosome __ in humans.

Answer 5

6

Question 6

Outline Class I MHC molecules.

Answer 6

In humans, HLA-A, HLA-B, and HLA-C code for this class. Additional genes code for non-classical Class I molecules, such as HLA-G, which gives protection for the foetus. Glycoproteins are expressed on the surface of almost all nucleated cells. Class I molecules present the antigens necessary for the activation of cytotoxic T (Tc)-cells. Molecules are comprised of two polypeptide chains; α chain has three extracellular domains, α1, α2, and α3. They deal with viral peptides

Question 7

Outline Class II MHC molecules.

Answer 7

HLA-DP, HLA-DQ, and HLA-DR genes code for this class; T-helper cells are associated. Glycoproteins are expressed on antigen-presenting cells. They present processed peptide antigen to T-helper (Th) cells, and comprise two polypeptide chains, an α chain and a β chain, spanning the membrane; the peptide binds in a groove. They deal with bacterial peptides

Question 8

Outline Class III MHC molecules.

Answer 8

The encode soluble serum proteins, and also encode some complement components.
Tumour necrosis factor TNFα and TNFβ, and other proteins, are also encoded

Question 9

_______ MHC has several genes within each class.

Answer 9

Polygenic

Question 10

Polymorphic means that there are multiple ________ of each gene.

Answer 10

Variants

Question 11

MHC molecules have a broad _______, as they can bind many, but not all, types of possible peptides.

Answer 11

Specificity

Question 12

The __________ play a central role in antigen presentation, implicit in the activation of T-cells; T-cells are described as ‘MHC restricted’.

Answer 12

Glycoproteins

Question 13

True or false: Class I glycoproteins are present on all nucleated cells.

Answer 13

True

Question 14

Class __ glycoproteins are present only on antigen-presenting cells.

Answer 14

II

Question 15

MHC molecules are involved in the killing of ________-_______ cells, with T-cytotoxic cells.

Answer 15

Virus-infected

Question 16

All _-cells are MHC-restricted, and they recognise peptides presented on the surface of antigen-presenting cells when bound by MHC molecules.

Answer 16

T

Question 17

The MHC is polygenic, and MHC ________ are highly polymorphic.

Answer 17

Alleles