Characterization of Infection and Replication of Mason-Pfizer Monkey Virus in Human Cell Cultures

Abstract

SUMMARYHuman cells derived from both normal and neoplastic tissues can be infected by Mason-Pfizer monkey virus (MPMV) without accompanying cytopathology. Infection of cell cultures such as human rhabdomyosarcoma (A2o4) results in a persistently infected cell line which can be subcultured over 3o sequential culture passages without significant change in phenotypic properties according to reverse, transcriptase (RT), MPMV p27 antigen content, virus particle count and infectivity titrel Productive virus infections were established at relatively low virus particle (VP) input multiplicities (p.i.m. ; about o.o6 VP/cell) in A2o4 cell cultures. At higher p.i.m. (about 6oo to 6ooo VP/cell) newly synthesized virus was detected within 4 days post infection. Although virus production was cumulative following primary infection, after subculture of infected cultures MPMV production was greater during active cell division. Using synchronization techniques, MPMV replication in persistently infected cultures was found to be cell cycle-dependent. The major internal antigen, P27, was synthesized in G2 and newly synthesized virus particles were released predominantly during mitosis and early G1. Colcemid arrest of cells during mitosis inhibited subsequent MPMV release. Consequently, production of extracellular virus depends upon the progression of cells through the mitotic stage. These data, which provided a basic understanding of the virushost relationship that occurs in primate cells productively infected with MPMV, were used as a guideline for isolating MPMV-like viruses from experimentally and naturally infected Rhesus monkeys.

A primate virus generates transformed human cells by fusion

“…Cell fusion was detectable within hours (Fig. 6 A), as opposed to the days required to express MPMV proteins (Fine et al, 1979), which is consistent with the finding that fused cells have no detectable MPMV proteins (Fig. S2 A, available at http://www.jcb.org/cgi/content/full/jcb.200507069/DC1).…”

Complete nucleotide sequence of simian endogenous type D retrovirus with intact genome organization: evidence for ancestry to simian retrovirus and baboon endogenous virus

“…An additional explanation could be that SRVpc is a recent product of recombination between an exogenous macaque virus and endogenous baboon sequences. Seropositivity for antibodies directed against type D virus proteins is regularly found in monkeys, both in the wild and in captivity (12,14,18,26). Neutralizing antibodies were observed to persist throughout life, suggesting that type D viruses can establish persistent infections.…”

“…This would indicate that endogenous type D monkey viruses can be, and have been, expressed. SRV-3 can productively infect human cells with a low input of virus particles, (12), and the virus is also able to spread rapidly in animal populations (as high as 90% seropositivity in primate centers in a few years). BaEV particles can be easily obtained by cocultivating baboon tissue with human cells (3).…”

Milk Transmission of Mammalian Retroviruses

“…MPMV ( Table 1 ), a rare Betaretrovirus , causes immunodeficiency in rhesus macaques [ 80 , 81 ]. This presents itself as AIDS-like symptoms, such as lymphadenopathy, weight loss, and severe opportunistic infections [ 82 , 83 , 84 ]. The transmission of the virus occurs horizontally and can be detected in saliva and milk in experimentally infected rhesus monkeys [ 84 , 85 ].…”