Question

How does your immune system tell the difference between invading pathogens and regular healthy cells that belong to our body? Describe the mechanism in detail, including the terms "cell surface marker", "cytokines" and "white blood cells". What happens when this mechanism fails and a person exhibits an autoimmune disease?

Answer 1

T- cells can differentiate between self and non self cell.

(antigen presenting cell) MHC II ( major histocompatibility complex) and MHCI ( target cell ) on their surface exhibit antigen peptides which are formed by cytosolic pathway in MHC I and endocytic pathway in MHC II . Antigen peptide are recognise by the helper T cell in MHCII and cytotoxic T cell in MHCI.

receptor present on the helper T cell bind to the antigen peptide. CD4 bind to class MHCII and CD8 bind to MHCI.

When T helper cell bind it releases the cytokines which signals the cytotoxic cell to kill the target cell.

T and B cells are the white blood cells and only the B cells forms the antibodies.