ABSTRACT
The production of granulocyte-macrophage colony-stimulating factor (GM-CSF) by lymphocytes was examined in murine malaria. When spleen cells or lymph node cells from P. berghei-infected mice were cultured in vitro with malaria antigen, the GM-CSF production correlated with the incubation time up to 72 hours. When lymphocytes obtained at various days after infection were cultured with the antigen, GM-CSF became detectable as early as 2 days after infection, reached a peak at day 9 and then rapidly decreased. Production of GM-CSF was antigen-specific, and related to the dose of antigen. Treatment of lymphocytes with anti-Thy-1.2 antibody and complement resulted in almost complete loss of GM-CSF-producing activity, while treatment with either anti-CD4 or anti-CD8 antibody and complement resulted in partial loss of GM-CSF-producing activity, indicating that both CD4+ and CD8+ T cells are involved in GM-CSF production in malaria. GM-CSF exhibits glycoprotein nature, and has an apparent molecular weight of 36,000. The molecular properties of this T-cell derived GM-CSF were compared with those of known lymphokine GM-CSF.