Question

What is cell mediated immunity?

Answer 1

The term cell mediated immunity (CMI) refers to protective mechanisms that are not primarily characterized by antibody. The CMI system is considered to have evolved, in a simpler form, very early as a way of recognizing self from non-self. While the humoral response mainly protects against extracellular pathogens and toxins, CMI is responsible for detecting and destroying intracellular pathogens, e.g., cells infected with viruses or bacteria. In addition, CMI is vital for graft rejection and destruction of tumor cells and for delayed-type hypersensitivity reactions. However, humoral and cell-mediated responses are similar in that both have innate and specific immune components. Among the common innate components is the antigen-presenting cell (APC), which interacts with T helper cells to initiate the immune response.