Cell mediated immunity is an
immune response that does not involve
antibodies, but rather involves the activation of
phagocytes,
antigen-specific
cytotoxic T-lymphocytes, and the release of various
cytokines in response to an antigen. Historically, the immune system was separated into two branches:
humoral immunity, for which the protective function of immunization could be found in the humor (cell-free bodily fluid or
serum) and
cellular immunity, for which the protective function of immunization was associated with cells. CD4 cells or helper T cells provide protection against different pathogens. Cytotoxic T cells cause death by
apoptosis without using cytokines, therefore in cell-mediated immunity cytokines are not
always present.