What is the difference between B-lymphocytes and T-lymphocytes?
B lymphocytes attack invaders outside the cell whereas t lymphocytes attack invaders inside the cell.
B lymphocytes are produced in the bone marrow and are primarily responsible for humoral immunity (production of antibodies). T lymphocytes are also produced in the bone marrow but they mature in the thymus and are responsible for cell mediated immunity. They kill infected cells directly without producing antibodies.