Key Points The complement system is a group of circulating proteins that promote inflammation and host defense. Unregulated tissue damage is a possible complication of complement activation; a large variety of circulating and membrane-bound proteins exist to regulate complement activity.…
Key Points Five different classes of antibody are known—immunoglobulin (Ig) M, IgG, IgA, IgD, and IgE—each with a distinct heavy chain. Two different light-chain types have been identified: κ and λ. Antigens react with antibodies at the Fab region, which…
Key Points The immune system consists of cellular and humoral components that defend the body against invading microorganisms. Deficiency of individual factors of the immune system can leave an individual susceptible to different infections. The lymphoid cells of the immune…