Which mitogens are demonstrated to stimulate B cells?

Pokeweed, lipopolysaccharide (LPS), and Staphylococcus aureus Cowan are recognized for their ability to stimulate B cells. Pokeweed mitogen is a potent B cell activator derived from the pokeweed plant, inducing proliferation and differentiation of B lymphocytes. Lipopolysaccharide is a component of the cell wall of gram-negative bacteria and serves as a strong mitogen that activates B cells, enhancing their antibody production and promoting their differentiation into plasma cells. Staphylococcus aureus Cowan strain is often used in laboratory settings to stimulate B cells due to its capacity to induce polyclonal activation.

The other answer choices include substances that may not directly stimulate B cells in the same capacity. For instance, phytohemagglutinin and concanavalin A are primarily T cell mitogens, which primarily activate T cells rather than B cells. Similarly, while pneumococcal antigens can elicit some response, they are not as effective as the combination of pokeweed, LPS, and Staphylococcus aureus Cowan for B cell stimulation in the context of mitogens. Therefore, the optimal combination found in choice B specifically demonstrates the strongest capability to activate B cells.