Interleukin 7 is a T-cell growth factor.

Interleukin 7 (IL-7) is a 25-kDa cytokine which was purified and its corresponding cDNA was cloned based upon its ability to stimulate the proliferation of pre-B cells. It has been shown that IL-7 can also function as a costimulator with Con A for the proliferation of T lymphocytes by inducing the production of interleukin 2 (IL-2). We demonstrate here that IL-7 in combination with phorbol 12-myristate 13-acetate can directly drive the proliferation of purified T cells and that this response is not inhibited by cyclosporine A or by antibodies to IL-2 and IL-4.

Nocardia.

N asteroides is an aerobic, gram-positive, partially acid-fast, branching rod. Cell-mediated immunity via both macrophage activation and direct cytotoxicity represents the main host defense. While clinical infection most commonly occurs in immunocompromised hosts, Nocardia can infect and exist as a saprophyte in normal hosts.