HSV-2 disrupts gap junctional intercellular communication between mammalian cells in vitro.

Infection by herpes simplex virus-2 (HSV-2) disrupts both dye and electrical coupling in Vero (African green monkey kidney) cell cultures. Vero cells in vitro were iontophoretically injected with the fluorescent dye Lucifer yellow CH, the spread of which revealed that cells throughout the confluent sheet shared open gap junctions. However, 24 h after infection with the virus (but before cells became rounded), dye always remained only within the target cell. Intracellular electrophysiological measurements of ionic coupling revealed a 0.4 coupling coefficient for adjacent cells in uninfected control cultures. By 3 h following infection significant down-regulation of gap junctions had begun, preceding by many hours any signs of infection visible with the light microscope. Measurements between adjacent cells 3 h post-infection, a period when HSV-2 gene expression is known to be at a maximum, yielded an average coupling coefficient of 0.35. By 6 h post-infection (a period of known viral DNA replication) average coupling coefficient for adjacent cells was 0.25, while by 24 h post-infection the average fill still further to <0.08. A coupling coefficient of <0.08 suggests that infection by HSV-2 completely disabled the gap junctions.

Effects of the angiotensin II receptor antagonist losartan on herpes simplex virus-type 2 infection of cultured vero and cardiac neonatal myocytes.

Previous studies indicate that captopril, an angiotensin II converting enzyme inhibitor, attenuates cardiomyopathy in a murine viral myocarditis model. Accordingly, we investigated the ability of captopril as well as angiotensin II (AII) and losartan, a nonpeptide AII receptor antagonist, to alter infection or replication of herpes simplex virus- type 2 (HSV-2) in cultured cardiac and vero cells. Neither captopril nor AII influenced the ability of HSV-2 to replicate in either cell type. Losartan, however, caused a dose dependent decrease in pfu ability on vero cells with an ED50 of 1.35 mM. In cultured myocytes, losartan (400 microM) reduced significantly %LDH released (54.9 +/- 7.5 vs 29.1 +/- 4.2 in infected controls) and % pfu released (40.9 +/- 8.4 vs 14.8 +/- 3.8 in infected controls) into the media. These results suggest that losartan attenuates deleterious effects of the virus by preventing release of the virus by the cells.

Nucleic acids of respiratory syncytial virus.

Analysis of purified respiratory syncytial virus revealed that the virion RNA was composed of 50S, 28S, 18S, and 4S species. The 18S and 28S species were presumed to represent host rRNA since virus grown in actinomycin D-treated cells contained only 50S and 4S RNAs. Actinomycin D treatment stimulated production of infectious respiratory syncytial virus 5- to 10-fold. The 50S virion RNA was shown to hybridize with polyadenylated mRNA's isolated from infected cells, indicating that respiratory syncytial virus RNA is of negative-strand sense. Six mRNA's were identified by polyacrylamide gel electrophoresis.