Glycoprotein D or J delivered in trans blocks apoptosis in SK-N-SH cells induced by a herpes simplex virus 1 mutant lacking intact genes expressing both glycoproteins

We have made two stocks of a herpes simplex virus 1 mutant lacking intact U (s)5 and U(s)6 open reading frames encoding glycoproteins J (gJ) and D (gD) , respectively. The stock designated gD(-/+), made in cells carrying U(s)6 and expressing gD, was capable of productively infecting cells, whereas the stock designated gD(-/-), made in cells lacking viral DNA sequences, was k nown to attach but not initiate infection. We report the following. (i) Bot h stocks of virus induced apoptosis in SK-N-SH cells. Thus, annexin V bindi ng to cell surfaces was detected as early as 8 h after infection. (ii) U(s) 5 or U(s)6 cloned into the baculovirus under the human cytomegalovirus imme diate-early promoter was expressed in SK-N-SH cells and blocked apoptosis i n cells infected with either gD(-/+) or gD(-/-) virus, whereas glycoprotein B, infected cell protein 22, or the wild-type baculovirus did not block ap optosis. (iii) In SK-N-SH cells, internalized, partially degraded virus par ticles were detected at 30 min after exposure to gD virus but not at later intervals. (iv) Concurrent infection of cells with baculoviruses did not al ter the failure of gD(-/-) virus from expressing its genes or, conversely, the expression of viral genes by gD(-/+) virus. These results underscore th e capacity of herpes simplex virus to initiate the apoptotic cascade in the absence of de novo protein synthesis and indicate that both gD and gJ inde pendently, and most likely at different stages in the reproductive cycle, p lay a key role in blocking the apoptotic cascade leading to cell death.