Interleukin 2 (IL-2) is a pleiotropic cytokine produced primarily by mitogen- or antigen-activated T lymphocytes (1, 2). Human IL-2 (also known as T-cell growth factor) is produced by T-cells in response to antigenic or mitogenic stimulation. IL-2 is a potent lymphoid cell growth factor which exerts its biological activity primarily on T cells promoting proliferation and maturation.
Additionally, IL-2 has been found to stimulate growth and differentiation of B cells, NK cells, LAK cells, monocytes, and oligodendocytes. IL-2 is involved in treatment of cancers such as melanoma and renal cell cancer. It plays a key role in promoting the clonal expansion of antigen-specific T cells. In addition, IL-2 has also been shown to mediate multiple immune responses on a variety of cell types.
The sequence of mouse IL-2 cDNA predicts a 169 amino acid (aa) residue precursor glycoprotein containing a 20 aa residue signal peptide that is cleaved to form the mature protein (3, 4). At the amino acid sequence level, mature mouse IL-2 is approximately 60% identical to human IL-2 (1, 2, 5). Whereas human IL-2 is active on mouse cells, mouse IL-2 is species-specific and is inactive on human cells (6). The gene for IL-2 has been mapped to mouse chromosome 3 (7).
The biological effects of IL-2 are mediated by specific cell surface receptor complexes. The functional high-affinity receptor for IL-2 is composed of three distinct polypeptide chains (8, 9).
IL-2 stimulates the proliferation of thymocytes; stimulates the proliferation and differentiation of activated B cells; promotes the growth, differentiation and cytocidal activity of monocytes; induces the growth of natural killer cells and stimulates cytokine production by these cells as well as the cytolytic activity of these cells; enhances the production of lymphocyte-activated killer (LAK) cells; and induces the proliferation and differentiation of oligodendrocytes (1).
Goldsmith, M.A. and W.C. Greene (1994) in The Cytokine Handbook, 2nd ed., A. Thomson editor, Academic Press, New York, p. 57.
Hatakeyama, M. and T. Taniguchi (1990) in Peptide Growth Factors and Their Receptors I, Sporn, M.B. and A.B. Roberts eds., Springer-Verlag, New York, p. 523.
Yokota, T. et al. (1985) Proc. Natl. Acd. Sci. USA 82:68.
Kashima, N. et al. (1985) Nature 313:401.
Taniguchi, T. et al. (1983) Nature 302:305.
R&D Systems, Unpublished results.
Fuse, A. et al. (1984) Nucl. Acids Res. 12:9323.
Kashima, N. et al. (1985) Nature 313:401.
Seigel, L.J. et al. (1984) Science 223:175.