The effect of growth hormone on the proliferation of human Th cell clones

The effects of human growth hormone (hGH) on human Th cell clones were examined. Both 20K and 22K hGH stimulated the proliferation of Th2 and Th0 cells in the presence of mite antigen, whereas they did not stimulate the proliferation of Thl cells. Because the effect of 20K hGH was almost the same as that of 22KhGH, it was suggested that the action of hGH was not mediated through prolactin receptor but through hGH receptors. The application of growth hormone binding protein (GHBP) inhibited the cell growth of Th1 clones. In Th2 and Th0 cells GHBP inhibited the hGH-stimulated cell proliferation. However, GHBP alone did not affect the proliferation of Th2 and Th0 cells. hGH was detected in the supernatant of Th1 clones in the presence of mite antigen but it was not detected in Th2 clones. hGH was detected in one out of 4 batches of Th0 clones. These data indicated that hGH was secreted from Thl clones, and that Th0 clones possessed characteristics of both Th2 and Th0 clones.