Induction of transforming growth factor-beta 1 production in human cells by herpes simplex virus

Transforming growth factor-beta (TGF-beta) is a cytokine of particular inte rest in human retrovirus infections because it can abrogate antigen-specifi c cellular activation. Although TGF-beta production has been observed in HI V infections, there is no evidence that herpes simplex virus (HSV)-stimulat ed human cells produce this cytokine, Here were present evidence, for the f irst time, that in vitro infection of human mononuclear cells with HSV type 1 (HSV-1) induced the release of TGF-beta 1 protein. The production of thi s cytokine was time dependent and was found highly significant (p < 0.001) after 48 h, In addition, me observed that the secretion of TGF-beta 1 was d ependent on the concentration of human cells. It was found that virus needs to replicate in human cells for the production of TGF-beta 1, as UV-inacti vated virus did not induce significant production of cytokine protein. Inte restingly, increased HSV-1-induced TGF-beta 1 production in cultures contai ning antiinterleukin (IL)-12 or antiinterferon (IFN)-gamma antibodies was o bserved, whereas an irrelevant antibody had no effect on the production of this cytokine, Taken together, these findings indicate that human cells syn thetize TGF-beta 1 in response to HSV-1 and at the same time suggest that H SV-1-induced TGF-beta 1 production mag be one of the mechanisms by which HS V can at least partly evade activation of the host immune system.