Human T helper cells reactive with somatic bacterial antigens belong to the Th1 subset.

The aim of this study was to characterize the cytokine secretion patterns of human T helper cells from healthy donors reactive with somatic antigens from various bacteria, the nematode Anisakis and tetanus toxoid. From the peripheral blood of four healthy donors we have established 70 T cell lines reactive with antigens from Yersinia, Salmonella, Morganella, Klebsiella, Serratia, Escherichia, Chlamydia, Shigella, Streptococcus, tetanus toxoid and Anisakis, respectively. Our results show that all T cells reactive with bacteria produce interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha), but no interleukin (IL)-4 and no or very little IL-2 and IL-10 and, thus, belong to the Th1 subset, while T cells reactive with tetanus toxoid or Anisakis belong to the Th0 subset with production of IFN-gamma, IL-2, IL-4, IL-10 and TNF-alpha. In summary, our data further substantiate the concept of a functional diversity of human T helper cells with respect to their cytokine profiles. Furthermore, they indicate that a Th1 cytokine profile is not restricted to intracellular bacteria.