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

Multiple Choice

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