MICROANATOMY

Detailed explanation-1: -B cell activation is initiated by the binding of antigen to the B cell receptor (BCR) that triggers a number of signaling cascades that ultimately lead to B cell activation.

Detailed explanation-2: -Activation of B cells A B cell becomes activated when its receptor recognizes an antigen and binds to it. In most cases, however, B-cell activation is dependent on a second factor mentioned above-stimulation by an activated helper T cell.

Detailed explanation-3: -Helper T cells are arguably the most important cells in adaptive immunity, as they are required for almost all adaptive immune responses. They not only help activate B cells to secrete antibodies and macrophages to destroy ingested microbes, but they also help activate cytotoxic T cells to kill infected target cells.