Mouse Anti-Human CD28 monoclonal antibody for in vitro T cell stimulation/activation. CD28 is a receptor for CD80 (B7-1) and CD86 (B7-2). Signaling through CD28 augments IL-2 and IL-2 receptor expression as well as cytotoxicity of CD3-activated T cells. This antibody has been shown to stimulate the proliferation of human T cells in vitro.