CD8

CD8, also known as cluster of differentiation 8, is a glycoprotein found on the surface of cytotoxic T cells. It plays a vital role in immune response and is involved in recognizing and killing infected or cancerous cells.

The primary function of CD8 is to bind to major histocompatibility complex (MHC) class I molecules on target cells. This interaction allows cytotoxic T cells to identify cells that are presenting foreign antigens and initiate their destruction.

CD8 and CD4 are glycoproteins involved in the immune response, but they have different roles. While CD8 is primarily found on cytotoxic T cells and plays a role in cellular immunity, CD4 is mainly found on helper T cells and contributes to both cellular and humoral immunity.

CD8 has two major subtypes: CD8α and CD8β. These subtypes form a heterodimer that enables CD8 to interact with MHC class I molecules more effectively.

The level of CD8 expression on cytotoxic T cells can indicate their activation state. Higher levels of CD8 often correspond to increased cytotoxicity and effector functions, while lower levels may suggest a more naive or less activated state.

CD8 plays a crucial role in the immune response against HIV. HIV specifically targets CD4, leading to the depletion of helper T cells. This depletion weakens the immune system and impairs the function of CD8 cytotoxic T cells, allowing the virus to persist and progress.

Yes, CD8 expression levels can serve as a diagnostic marker for various diseases. For example, increased CD8 expression in certain tissues or blood samples may indicate viral infections, autoimmune diseases, or certain types of cancers.

Several immunotherapies aim to modulate CD8 T cell responses. These include immune checkpoint inhibitors that block proteins like PD-1 or CTLA-4, which can suppress CD8 activity. Other strategies involve adoptive T cell therapy or vaccines that target specific antigens recognized by CD8 T cells.

Yes, CD8 T cells play a role in transplant rejection. If the transplanted organ is perceived as non-self by the recipient's immune system, CD8 cytotoxic T cells can recognize and attack the foreign tissue, leading to graft rejection.

CD8 deficiency can contribute to immunodeficiency disorders, impairing the body's ability to mount an effective immune response against pathogens. This condition is rare and usually results from genetic mutations affecting CD8 production or function.