Using a combination of cellular and molecular attacks, the innate immune system identifies the nature of a pathogen and responds with inflammation, phagocytosis, cytokine release, destruction by NK cells, and/or a… T H cells stimulate B cells that have engulfed and presented pathogen-derived antigens.

APCs display antigens via MHC molecules to complementary naïve T cells. The innate immune system serves as a first responder to pathogenic threats that bypass natural physical and chemical barriers of the body.

cytokine — chemical messenger that regulates cell differentiation, proliferation, gene expression, and cell trafficking to effect immune responses. inflammation — localized redness, swelling, heat, and pain that results from the movement of leukocytes and fluid through opened capillaries to a site of infection. T cell — lymphocyte that matures in the thymus gland; one of the main cells involved in the adaptive immune system. B cell — lymphocyte that matures in the bone marrow and differentiates into antibody-secreting plasma cells.