Final answer:
The membrane attack complex is not formed by major histocompatibility (MHC) proteins. MHC proteins have a different function in the immune system. The membrane attack complex is formed by complement proteins as part of the complement system.
Step-by-step explanation:
The statement is false.
The membrane attack complex (MAC) is not formed by major histocompatibility (MHC) proteins. MHC proteins, specifically MHC class I and MHC class II molecules, have a different function in the immune system.
MHC I molecules present antigens to cytotoxic T cells, while MHC II molecules present antigens to helper T cells. The membrane attack complex is formed as part of the complement system, which is activated by antibodies attached to the surface of a pathogen. The MAC consists of complement proteins C5, C6, C7, C8, and C9, which together create a hole in the pathogen's plasma membrane, leading to lysis.