any functional anomaly of the aspect of immunity that is mediated by secreted antibodies produced in the cells of the B lymphocyte lineage (B cell) and the accessory processes that accompany it, including Th2 activation and cytokine production, germinal center formation and isotype switching, affinity maturation and memory cell generation; it also refers to the effector functions of antibody, which include pathogen and toxin neutralization, classical complement activation, and opsonin promotion of phagocytosis and pathogen elimination
