Responses of pokeweed mitogen-stimulated peripheral mononuclear cells to human recombinant interleukins 3 and 4

Peripheral blood mononuclear cells (PBMC) that had been stimulated with a polyclonal B cell activator, pokeweed mitogen (PWM), were examined for mitogenic responsiveness to interleukins (IL) and colony stimulating factors (CSF) or other cytokines using recombinant preparations from E. coli or Cos cells expressing their cloned cDNAs. PWM-stimulated PBMC (PWM-blasts) were found to be responsive to IL-3 depending upon the concentrations of the agent. Mitogenic response of PWM-blasts in the reaction to IL-3 was suppressed by the addition of a specific monoclonal antibody against IL-3 but not by anti-IL-2 serum, excluding the possibility that the DNA replication induced by IL-3 is a result of the proliferative response of IL-2 responder cells to IL-2, which might be produced during the culture of PWM-blasts in the presence of IL-3. The PWM-blasts were also responsive to IL-2 and IL-4 but not to other interleukins, namely, IL-1, IL-5 and IL-6, nor to granulocyte/macrophage (GM)-, granulocyte (G)- nor macrophage (M)-CSFs. They were also not responsive to interferon gamma. Similar responsiveness to IL-3 and IL-4 was found in the PBMC stimulated with a B-cell mitogen, Staphylococcus aureus Cowan 1 (Sac-1), but not in the PBMC stimulated with T cell mitogens, PHA or ConA. These results suggest that the human PBMC stimulated with B cell mitogens such as PWM or Sac-1 contain activated IL-3- and IL-4- responsive cells in sufficient number to detect these lymphokine activities.(ABSTRACT TRUNCATED AT 250 WORDS)