For some reason, the answer doesn't make sense -- Antibodies are secreted by A.memory B cells. B.plasma cells. C.memory T cells. D.cytotoxic T cells. E.helper T cells. They say the answer is B, plasma B cells. But aren't antibodies also secreted from memory B cells? (...whenever antigens are introduced a second time?) Isn't that the point of vaccines? -Hope someone can explain why A can't be the right answer.