Interleukin Futures

The so-called interleukin-2 inhibitory activity of human serum is largely cytotoxic to mouse cells

No specific interleukin-2 (IL-2) inhibitor has ever been demonstrated in human, mouse, or any other animal serum. Native mouse serum contains activities which completely inhibit IL-2-dependent and IL-2-independent in vitro proliferation of cells of different animal species by a non-cytotoxic mechanism. The decisive inhibitory component of mouse serum has a molecular weight of about 80,000, is heat-labile and has not been found in other animal sera. Also, native human serum completely suppresses the proliferation of various mouse cell types, predominantly by a cytotoxic effect caused by natural IgM antibodies and complement. Heat-inactivated human serum is no longer cytotoxic to mouse cells, and inhibits the proliferation of mouse cells much less than native serum. There is thus no evidence for a specific IL-2 inhibitor in mouse, human or other serum.

The biology and clinical potential of growth factors that regulate myeloid cell production

The colony-stimulating factors are a group of growth factors important in regulating the production of myeloid cells. The past 25 years have seen the identification and characterization of many of these growth factors and, more recently, the molecular cloning of their genes. This has enabled the production of sufficient quantities to assess their biological activity in vivo and in vitro. Some of these recombinant growth factors have also been employed in clinical trials, which have indicated potential uses in the treatment of a variety of diseases. Here, Anthony Whetton considers the biology of haematopoietic growth factors, and the evidence that they may be of value in the treatment of haematopoietic, infectious and malignant disease.