Question

Which of the following are TRUE of class I major histocompatibility complex (MHC) molecules?

A. Class I MHC molecules present exogenous antigens.
B. Class I MHC molecules are only present on erythrocyte surfaces.
C. Class I MHC molecules bind complement.
D. Class I MHC molecules present endogenous antigens.

Answer 1

Class I MHC molecules are found on all nucleated cells and present both normal self-antigens and abnormal/nonself pathogens. Class II MHC molecules are found on antigen-presenting cells and present abnormal/nonself pathogen antigens for T cell activation.

Step-by-step explanation:

Class I major histocompatibility complex (MHC) molecules are found on all nucleated cells and are responsible for presenting both normal self-antigens and abnormal or nonself pathogens to effector T cells involved in cellular immunity. They are essential for marking infected cells for destruction by presenting foreign antigens on the cell surface.

On the other hand, class II MHC molecules are only found on antigen-presenting cells, such as macrophages, dendritic cells, and B cells. They present abnormal or nonself pathogen antigens for the initial activation of T cells.