Early message expression of interleukin-4 and interferon-gamma, but not of interleukin-2 and interleukin-10, reflects later polarization of primary CD4+ T cell cultures.

The CD4+ T cell subpopulation identified by the Mel-14high phenotype represents naive T cells that develop into T helper 1 (Th1) cells upon stimulation with anti-CD3 and interleukin (IL)-2; however, the addition of IL-4 induces the development of high IL-4, IL-5 and IL-10-secreting cells (IL-4 SC). Here, we investigate the timing of cytokine gene expression in purified naive, Mel-14high CD4+ T cells after stimulation under conditions that induce one of three dramatically different populations following secondary stimulation: anti-CD3 + IL-2 (Th1), anti-CD3 + IL-2 and IL-4 (IL-4 SC) and anti-CD3 + anti-interferon (IFN)-gamma/anti-IL-4 (null population). The skewing toward IL-4 SC development induced by IL-4 in the primary stimulation was clearly visible by 40 h. The message for IL-4 was absent at 20 h after stimulation, but was induced 30-100-fold by 40 h and was accompanied by a decrease in IFN-gamma message. The message for IL-5 was undetectable. The development of Mel-14high T cells into a Th1 population follows kinetics similar to those of the development of IL-4 SC in that IFN-gamma gene transcription was undetectable at 20 h and induced 100-fold by 40 h post-stimulation. This induction was inhibited by the inclusion of anti-IFN-gamma/anti-IL-4 during the primary stimulation. Finally, IL-10 message is present in both cultures that developed into IL-4 SC and those that developed into Th1 populations, in contrast to the differentiated cultures where there is a segregation between IL-10 and IFN-gamma expression. Undetectable levels of message for both IL-2 and IFN-gamma were seen in the null cultures, which expressed both IL-2 and IL-10 message. T cells identified by the Mel-14low phenotype develop into a population that secretes high levels of all cytokines tested, and this phenotype was revealed within 20 h after stimulation as determined by message analysis. These results demonstrate an early correlation of gene transcription for IL-4 and IFN-gamma, with the development of IL-4 SC and Th1 cells, and a lack of a correlation at these early time points for expression of IL-2, IL-5 and IL-10.