Discovery of interleukin-2 (IL-2)

1976

Challenge

In the 1970s, researchers sought to define whether retroviruses are causative agents of human diseases, including cancers. In order to discover and study human retroviruses, researchers first needed to identify a way to grow and maintain T lymphocytes, or T-cells, long-term in the lab.

Advance

IRP researchers led by Robert Gallo, M.D., found a way to successfully grow T-cells in culture for more than nine months. They accomplished the feat by first stimulating lymphocytes with phytohemagglutinin, a protein found in plants, and then examining for the production of potential growth factors in the culture fluid. The team identified T-cell growth factor (TCFG), now known as interleukin-2 (IL-2).

Impact

The discovery and purification of IL-2 allowed researchers to grow T-cells and study their immunology, which led to the discovery of human T-cell leukemia virus (HTLV), the first retrovirus identified in humans.

Publications

Morgan DA, Ruscetti FW, Gallo R (1976). Selective in vitro growth of T lymphocytes from normal human bone marrows. Science. 193(4257):1007–8.

Mier JW, Gallo RC (1980). Purification and some characteristics of human T-cell growth factor from phytohemagglutinin-stimulated lymphocyte-conditioned media. Proc Natl Acad Sci U S A. 77(10):6134-8.