Serial propagation of porcine group C rotavirus (pararotavirus) in a continuous cell line and characterization of the passaged virus

Abstract

The Cowden strain of porcine group C rotavirus (pararotavirus) was adapted to serial passage in a continuous monkey kidney cell line (MA104). Key factors in its successful adaptation included use of virus passaged in primary porcine kidney celis as the initial inoculum, use of roller tubes, and addition of pancreatin to the maintenance medium. A cell culture immunofluorescence test was used to quantitate the virus at each passage level, since a possible cytopathic effect was obscured by the effects of pancreatin. The virus titers dropped after initial passage into MA104 cells but increased thereafter, with peak titers evident after 16 passages (107 immunofluorescence U/ml). Immune electron microscopy and genome electropherotyping were used to identify group C rotàvirus particles and confirm group C rotavirus double-stranded RNA gel migration patterns, respectively, from infected cell culture supernatants. The electropherotype of the cell culturepropagated group C rotavirus was identical to that of the gut virulent virus from which it was derived. The cell culture-passaged group C rotavirus also retained its infectivity-for gnotobiotic pigs. No group A rotavirus was detected in the intestinal contents of the pigs or in cell culture fluids from group C rotavirus-inoculated monolayers with the two former techniques or the cell culture immunofluorescence test. This is the first verified report of serial propagation of a non-group A rotavirus in a continuous cell line.

Sequence conservation of the major outer capsid glycoprotein of human group C rotaviruses

“…Unlike many human group A rotaviruses, human group C rotaviruses cannot be propagated in cell culture. However two animal group C rotavirus isolates (porcine and bovine) have been adapted to growth in cell culture [Saif et al, 1988;Tsunemitsu et al, 19911. As a result most of our basic knowledge stems from studies of the prototype (Cowden) porcine strain.…”

Reactivity of monoclonal antibodies to the 41-kilodalton protein of porcine group C rotavirus with homologous and heterologous rotavirus serogroups in immunofluorescence tests

“…Other rotavirus serogroups used in this study included the porcine (OSU and Gottfried) and bovine (NCDV) gp A rotaviruses and the porcine (Ohio) and bovine (ATI) gp B rotaviruses (26,29,35). Each rotavirus strain (except the three field strains) was inoculated onto MA104 cell monolayers for use in IF tests as described previously (2,28,29,33,34).…”

Isolation and serial propagation of human group C rotaviruses in a cell line (CaCo-2)

“…Only two reports of the replication of group C rotaviruses, one isolated from swine and the other from a bovine source, have been published [Saif et al, 1988;Tsunemitsu et al, 19911. We propagated group C rota- Fig. 4.…”