Final answer:
Antibody-mediated (type II) hypersensitivity, or cytotoxic hypersensitivity, occurs when IgG and IgM antibodies bind to antigens on cells, causing cell damage through complement activation and inflammation, also known as cytotoxic reactions.
Step-by-step explanation:
Antibody-mediated (Type II) Hypersensitivity:
The correct answer to your question is a) Cytotoxic reactions. Antibody-mediated (type II) hypersensitivity is characterized by the binding of IgG and IgM antibodies to cell-surface or matrix-associated antigens. The subsequent immune response can lead to the activation of complement, resulting in inflammation and lysis of targeted cells. This response can also involve antibody-dependent cell-mediated cytotoxicity (ADCC) with cytotoxic T cells which contributes to the cytotoxic reactions.
Type III hypersensitivity differs as it involves immune complex reactions that lead to tissue damage whereas Type IV is a T-cell mediated response and Type I involves an immediate allergic reaction with the release of inflammatory molecules by mast cells.