Effects of prostaglandin E₂ and preincubation on lectin-stimulated proliferation of human T cell subsets

Our laboratory as well as others has previously noted that sensitivity of lymphocytes to inhibition by prostaglandin (PG)E₂ is lost after overnight preincubation. We now show that the change in sensitivity to PGE₂ with preincubation varies depending upon the T-cell subset in the culture. In phytohemaglutinin (PHA)-stimulated cultures of fresh cells, PGE₂ inhibits proliferation of T cells as well as OKT4 (+) cells and OKT8(+) cells. In PHA-stimulated cultures of preincubated cells, PGE₂ slightly augments proliferation of T cells; however, PGE still inhibits OKT4(+) cells and causes marked augmentation of OKT8(+) cells. Thus the "loss in sensitivity" to PGE₂ with preincubation is actually a result of the balancing effect of PGE₂ inhibiting OKT4(+) cells and stimulating OKT8(+) cells.