Question

how does B cells direct humoral immunity

Answer 1

Humoral immunity is mediated by secreted antibodies.The first exposure to a microbe or an antigen, either by infection or by vaccination, leads to the activation of B lymphocytes. These B cells differentiate into antibody-producing plasma cells and memory cells.
b-cells specific antigens stimulate b-cell production and it multiplies to produce a clone of plasma cells. The cells are differentiated into memory and effector cells due to clonal selection. They produce antibodies that circulate in body fluid and kill the pathogens