TH1 cells control themselves by producing interleukin-10

Abstract

Recent studies have shown that the anti-inflammatory cytokine interleukin-10 can be produced by T helper 1 cells. In this Progress article, Anne O'Garra and Paulo Vieira discuss the implications of these studies and the outstanding questions that they now raise. Inflammatory T helper 1 (TH1)-cell responses successfully eradicate pathogens, but often also cause immunopathology. To minimize this deleterious side-effect the anti-inflammatory cytokine interleukin-10 (IL-10) is produced. Although IL-10 was originally isolated from TH2 cells it is now known to be produced by many cell types. Here, we discuss the recent evidence that shows that TH1 cells are the main source of IL-10 that controls the immune response against Leishmania major and Toxoplasma gondii infection.