Final answer:
The main difference between CD8 T cells and CD4 T cells pertains to their distinct functions; CD8 T cells are cytotoxic and kill infected cells, while CD4 T cells are helper cells that release cytokines and assist other immune cells. MHC I molecules are found on all nucleated cells and present antigens to CD8 T cells, whereas MHC II molecules are on professional APCs and present to CD4 T cells. The false statement in the provided information is the one suggesting that MHC II is found on most body cells.
Step-by-step explanation:
The difference between CD8 T cells (which interact with MHC I) and CD4 T cells (which interact with MHC II) primarily lies in their functions within the immune system. CD8 T cells, also known as cytotoxic T cells, are responsible for directly killing infected or abnormal cells, often by inducing apoptosis, whereas CD4 T cells, also known as helper T cells, aid in the immune response by secreting cytokines and stimulating other immune cells such as B cells and other T cells.
Statement C from the provided information is false because MHC II is not found on most body cells; it is primarily present on professional antigen-presenting cells (APCs) such as dendritic cells, macrophages, and B cells. In contrast, MHC I is found on all nucleated cells and not only on immune cells. Both CD4 and CD8 T cells express the T cell receptor (TCR) to recognize antigens. However, CD4 T cells recognize antigen presentation in association with MHC II molecules, while CD8 T cells recognize antigens in conjunction with MHC I molecules.
The coreceptors CD4 and CD8 are crucial in determining the specificity of the TCR engagement with either MHC I or MHC II, respectively. This difference is critical in understanding the mechanisms of cell-mediated immunity versus other immune responses.