MICROANATOMY

Detailed explanation-1: -The third line defense aims at eliminating specific pathogens that have been encountered by the immune system previously (adaptive or acquired immune response). Instead of being restricted to the site of infection, the adaptive immune response occurs throughout the body.

Detailed explanation-2: -The second line of defense against non-self pathogens is called adaptive immune response. Adaptive immunity is also referred to as acquired immunity or specific immunity and is only found in vertebrates. The adaptive immune response is specific to the pathogen presented.

Detailed explanation-3: -Type 3 immunity encompasses innate and adaptive immune responses mediated by cells that produce the signature cytokines IL-17A and IL-17F. This class of effector immunity is particularly adept at controlling infections by pyogenic extracellular bacteria at epithelial barriers.

Detailed explanation-4: -Adaptive immune responses are carried out by white blood cells called lymphocytes. There are two broad classes of such responses-antibody responses and cell-mediated immune responses, and they are carried out by different classes of lymphocytes, called B cells and T cells, respectively.