What kind of T cells have CD8+ co-receptors?

Cytotoxic T cells are characterized by having CD8+ co-receptors on their surface. These CD8+ T cells play a crucial role in the immune response by directly targeting and killing infected cells, particularly those infected by viruses, and cells that are cancerous. The presence of CD8 allows these T cells to recognize antigens presented by Major Histocompatibility Complex (MHC) class I molecules, which are found on all nucleated cells. When a cytotoxic T cell recognizes an infected or abnormal cell, it can release cytotoxic granules that induce apoptosis in those cells, helping to eliminate the threat.

In contrast, helper T cells have CD4+ co-receptors and primarily assist in activating other immune cells, such as B cells and macrophages, rather than directly killing infected cells. Regulatory T cells also do not carry the CD8 co-receptor; instead, they often express CD4 and play a role in maintaining immune tolerance and preventing autoimmune responses. Memory T cells can arise from both helper and cytotoxic T cells, but their primary function is to provide a rapid response upon re-exposure to the same antigen, and they do not define a specific co-receptor. Given this context, cytotoxic T cells' unique