The number of major histocompatibility (MHC) protein isoforms possible in a given human population is enormous. However, each individual has a limited array of MHC molecules because ________.
A) the MHC proteins are made from several different gene regions that are capable of rearranging in a number of ways
B) MHC proteins from one individual can only be of class I or class II
C) each of the MHC genes has a large number of alleles, but each individual inherits only two for each gene
D) once a B cell has matured in the bone marrow, it is limited to two MHC response categories
E) once a T cell has matured in the thymus, it can only respond to two MHC categories

Question

Quizplus · Accepted Answer

Each individual inherits two alleles (one from each parent) for each of the MHC genes, which limits the array of possible MHC molecules. While MHC proteins are made from multiple gene regions that can rearrange, and there are different classes of MHC molecules, these factors alone do not explain why each individual has a limited array of MHC molecules.

The Number of Major Histocompatibility (MHC) Protein Isoforms Possible in a Given