PATHOLOGY

Detailed explanation-1: -Active Immunity Vaccine-induced immunity is acquired through the introduction of a killed or weakened form of the disease organism through vaccination.

Detailed explanation-2: -The function of adaptive immune responses is to destroy invading pathogens and any toxic molecules they produce. Because these responses are destructive, it is crucial that they be made only in response to molecules that are foreign to the host and not to the molecules of the host itself.

Detailed explanation-3: -Antigen-presenting cells, T cells, and B cells aggregate within the Peyer’s patch, forming organized lymphoid follicles. There, some T cells and B cells are activated. Other antigen-loaded dendritic cells migrate through the lymphatic system where they activate B cells, T cells, and plasma cells in the lymph nodes.