Question

Which immune cells bind MHC molecules on APCs via CD8 coreceptors on their cell surfaces?

a) Helper T cells
b) B cells
c) Natural Killer (NK) cells
d) Macrophages

Answer 1

Cytotoxic T lymphocytes (CTLs), which express CD8 coreceptors, bind MHC I molecules on antigen-presenting cells (APCs). The correct answer is option a).

Step-by-step explanation:

The immune cells that bind MHC molecules on antigen-presenting cells (APCs) via CD8 coreceptors on their surfaces are cytotoxic T lymphocytes (CTLs). Naïve T cells that express CD8 on their surface interact with MHC I molecules presented on APCs and become CTLs.

These cytotoxic T cells (also referred to as killer T cells) are instrumental in the immune response as they have the capability to directly kill infected cells through the process of apoptosis. It is important to note that while helper T cells (TH) also bind to APCs.

They do so via CD4 coreceptors and engage with MHC II molecules, not MHC I molecules. Therefore, the specific interaction between CD8+ T cells and MHC I molecules on APCs is distinctive to cytotoxic T cells, which play a different role compared to helper T cells in the immune response.