Type II hypersensitivity: what's the Mechanisms of Antibody-Mediated Tissue Injury?

Antibodies against tissue antigens (cells or extracellular matrix) induce inflammation by attracting and activating leukocytes. IgG antibodies bind to neutrophil and macrophage Fc receptors and activate these leukocytes, resulting in inflammation. IgG, as well as IgM antibodies, activate the complement system by the classical pathway, resulting in the production of complement by-products that recruit leukocytes and induce inflammation. When leukocytes are activated at sites of antibody deposition, these cells release reactive oxygen species and lysosomal enzymes that damage the adjacent tissues.