H. H. Barahona

Herpesvirus saimiri. III. Plaque Formation Under Multi Agar, Methyl Cellulose and Starch Overlays

Summary Herpesvirus saimiri produced plaques in cultures of fetal squirrel monkey heart, lung, intestine, and kidney and in owl monkey kidney and marmoset kidney cell cultures. The plaque populations in all cell types were heterogeneous in respect to size. Harvests of single plaques produced heterogeneous plaque populations on serial plating. Plaques were most numerous under methyl cellulose. Under agar, plaques were less numerous but were larger. Protamine sulfate and, to a limited degree, DEAE-dextran stimulated plaque production under agar while arginine had no effect. Plaques also formed under starch but were difficult to visualize. The number of plaques was directly proportional to the virus dilution, was also proportional to the volume of the inoculum, and was reduced by specific antiserum.

In Vitro Suppression of Herpesvirus saimiri Replication by Phosphonoacetic Acid

Summary Replication of Herpesvirus sai-miri was inhibited by 60 μg/ml of phospho-noacetic acid (PAA) in owl monkey kidney cell cultures (OMK). OMK cells were not adversely affected by PAA. Concentrations over 1 mg/ml of PAA proved toxic to OMK cells. Pretreatment of virus or cells prior to infection had no inhibitory effect on HVS. The continued presence of PAA was required to suppress HVS replication. Removal of the drug from infected cell cultures even after 63 days resulted in the appearance of cytopathogenic effect. PAA had a greater degree of inhibition on HVS than Herpes hominis type 1.

Herpes virus aotus: a latent herpesvirus from owl monkeys (Aotus trivirgatus) isolation and characterization.

Summary An uninoculated batch of owl monkey kidney cell cultures yielded a viral agent 23 days after the cell culture was initiated. This agent possessed the physical, chemical, cytopathic, histological, and ultrastructural properties of a herpesvirus. Random testing of owl monkey sera showed the presence of high titered neutralizing antibodies against this new agent. Herpesvirus simplex, Herpesvirus T., Herpesvirus B, Herpesvirus suis, Herpesvirus saimiri, infectious bovine rhinotraecheitis, and Herpesvirus saguinus, OMKI 372, and OMKI 68-69 antisera failed to neutralize the infectivity of this new agent. In cell cultures the virus grew best in cells of owl monkey origin. It also grew (poorly) in cebus monkey kidney cell cultures, some batches of squirrel monkey kidney cells, in Vero, BSC-1, human embryonic lung, whole human embryo and human embryo skin and muscle cells. It failed to form plaques under an agar overlay and does not form pocks on chorioallantoic membranes of embryonated eggs. Based on these findings, the name Herpesvirus aotus has been suggested. Owl monkey kidney cell cultures and owl monkey sera, when used for any work with other members of the herpesvirus group, ought to be employed with caution. The case reported here represents the first herpesvirus isolated from an owl monkey. Even though the pathogenic spectrum of this virus has not been established, being a herpesvirus, it should be regarded as potentially dangerous. Investigators who use owl monkeys should be aware of this new herpesvirus.

Herpesvirus Saimiri: In Vitro Sensitivity to Virus-Induced Interferon and to Polyriboinosinic Acid: Polyribocytidylic Acid

Summary The sensitivity of H. saimiri to virus-induced interferon and to the synthetic polynucleotide Poly I:C was determined in OMK cell cultures. These studies indicated that H. saimiri is relatively insensitive to the interferon activity in cultures pretreated for 6 hr with NDV-induced interferon. The degree of protection was improved when the cells were kept in interferon medium after the challenge with the virus. A direct pretreatment of the cells with low doses of Poly I:C induced a good protection which was greatly increased by a simultaneous addition of DEAE-D in the medium. The action of the Poly I:C/DEAE-D complex was considerably more effective when the treatment was initiated 1 hr after the inoculation of the virus. These findings suggest that the use of synthetic polynucleotides might prove to be useful for the inhibition of the malignancy produced by H. saimiri in susceptible nonhuman primates.