Release and effect of prostaglandin E2 in cocultures of lymphocytes and human tubular cells.

: Prostaglandin E2 reduced the expression of HLA-ABC as well as HLA-DR antigens in cultured human tubular cells, when cells were stimulated by gamma-interferon. The PGE2 release was low in tubular cell cultures, but highly increased by coculture of tubular cells and allogeneic lymphocytes, compared to cultures of unstimulated lymphocytes, or to cocultures with autologous lymphocytes. Cocultures between non-adherent mononuclear cells and tubular cells produced low amounts of PGE2, whereas cocultures of adherent monocytes and tubular cells produced equal as much PGE2 as cultures made with stimulated peripheral blood leucocytes. The adherent cells were dominated by macrophages. The proliferative response of lymphocytes in cocultures with tubular cells was low, and was increased by indomethacin. The results indicated, that presence of monocytes adherent to the tubular cells in cocultures, down-regulate the proliferative response of allogeneic lymphocytes to the tubular cells, which may in part attribute to an inhibitory effect of PGE2.