ENDOGENOUS TGF-BETA CONTRIBUTES TO THE INDUCTION OF THE EBV LYTIC CYCLE IN 2 BURKITT-LYMPHOMA CELL-LINES

A low proportion of cells in the BL lines P3HR-I and Akata enter spont aneously into the EBV lytic cycle, detectable by the expression of ear ly antigens (EA). We found that both lines produce the active and inac tive forms of TGF beta. It was shown earlier that a larger number of c ells can be induced to enter the lytic cycle by exposing P3HR-I to pho rbol esters and n-butyrate and the surface IgG-positive Akata cells to anti-IgG. We now show that the same treatments raise the level of act ive TGF beta release. Exposure to anti-TGF beta antibodies reduced EA induction by 75-85%. Our results indicate that induction of the viral productive cycle by the above-mentioned reagents is at least partly de pendent on the activation of endogenous TGF beta production. (C) 1994 Wiley-Liss, Inc.