"humoral response" Figure 9.1The humoral immune
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Figure 9.1The humoral immune response is mediated by antibody molecules that are secreted by plasma cells
"Antigen that binds to the B-cell antigen receptor signals B cells and is, at the same time, internalized and processed into peptides that activate armed helper T cells. Signals from the bound antigen and from the helper T cell induce the B cell to proliferate and differentiate into a plasma cell secreting specific antibody (top two panels). These antibodies protect the host from infection in three main ways. They can inhibit the toxic effects or infectivity of pathogens by binding to them: this is termed neutralization (bottom left panel). By coating the pathogens, they can enable accessory cells that recognize the Fc portions of arrays of antibodies to ingest and kill the pathogen, a process called opsonization (bottom center panel). Antibodies can also trigger activation of the complement system. Complement proteins can strongly enhance opsonization, and can directly kill some bacterial cells (bottom right panel)."