What is the purpose of CD-4 and CD-8 receptors on T cells?

• A. Facilitate communication between B and T cells
• B. Help maintain the protein/MHC complex
• C. Activate cytotoxic functions of T cells
• D. Stimulate antibody production by B cells

Answer: (B)

The CD-4 and CD-8 receptors on T cells play a crucial role in the immune response by recognizing and binding to Major Histocompatibility Complex (MHC) molecules on antigen-presenting cells. CD-4 receptors are primarily found on helper T cells, which recognize MHC class II molecules, while CD-8 receptors are found on cytotoxic T cells, recognizing MHC class I molecules.

The primary purpose of CD-4 and CD-8 receptors is to maintain the stability and interaction of T cells with these MHC complexes, allowing for effective signaling and subsequent activation of T cells. This interaction is vital for the immune system's ability to differentiate between self and non-self entities, which is essential for targeting infected or abnormal cells.

By facilitating the proper recognition of antigens presented by MHC molecules, these receptors help initiate the appropriate immune response, enabling helper T cells to activate other immune cells and cytotoxic T cells to destroy infected or tumor cells.