The following is a B cell specific mitogen:

Mitogens: Molecules that promote cellular mitosis in a non-specific way are known as mitogens. They activate lymphocytes but bypass antigen receptor specificity. Concanavalin A (conA), Phytohaemagglutinin (PHA) and wheat gram agglutinin (WGA) promote human T cell proliferation. Lipopolysaccharide (LPS) is specific for B cell, while Pokeweed mitogen (PWM) promotes both T cell and B cell. Ref: Analytical Techniques, edited by T.P. Mommsen, Peter W. Hochachka, Page 346, 347 ; The Immune Response: Basic and Clinical Principles, By Tak W. Mak, Mary E. Saunders, Page 387