Plaque formation by avian infectious bronchitis virus in primary chick embryo fibroblast cells in the presence of trypsin

Abstract

Ten strains of avian infectious bronchitis virus (IBV) were titrated as plaque-forming units in primary chick embryo fibroblast cells. In the absence of trypsin, plaques were only formed by Beaudette-42 and Iowa-609 strains. When trypsin was incorporated in the overlay medium of cell monolayers, all the IBV strains tested produced plaques within 4 days after inoculation. Incorporation of 20-40 microgram of trypsin per ml of the overlay medium seemed to be suitable for plaque formation of IBV. A preliminary investigation was made of the mode of action of trypsin.

The Biology of Coronaviruses

“…Virions grown in cells treated with tunicamycin lack the peplomer protein and are unable to attach to cells or initiate infection. There are indications that for some coronaviruses proteolytic processing of the peplomer protein during morphogenesis may be involved in activating functions such as virus-induced cell fusion (Dea et al, 1980;Otsuki & Tsubokura, 1981;Storz et al, 1981b). In addition to these characteristic proteins, others which do not appear to fit into any consistent pattern have been described, notably a 14000 mol.…”

Suppression of Influenza Virus Replication in Infected Mice by Protease Inhibitors

“…Since hostdependent proteolytic activation of virus infectivity is a universal mechanism in infection induced by influenza viruses (Klenk et al, 1975;Lazarowitz & Choppin, 1975;Bosch et al, 1979;Sugawara et al, 1981) and paramyxoviruses (Homma & Ohuchi, 1973 ;Scheid & Choppin, 1974;Nagai et al, 1976;Nagai & Klenk, 1977), protease inhibitors may be used for treatment of infection induced by most myxoviruses. Moreover, this approach may be valuable in therapy of a wide spectrum of viral diseases because many other viruses, including poxviruses (Ichihashi & Oie, 1982), reoviruses (Wallis et al, 1966;Rubin & Fields, 1980), retroviruses (Chang & Friedman, 1977;Pitha et al, 1978;Van der Hoorn et aI., 1983), rotaviruses (Estes et al, 1981) and coronaviruses (Otsuki & Tsubokura, 1981;Stroz et al, 1981), require proteolytic activation for their replication and pathogenicity. Thus, antiprotease compounds seem to be potential universal antiviral drugs.…”

Infection of HeLa cells by avian infectious bronchitis virus is dependent on cell status

“…Only a few IBV strains, such as the Beaudette (IBV-42) and Holte, have been shown to replicate in mammalian cell lines such as Vero and BHK cells after adaptation (Fang et al, 2005). At least two reports have demonstrated that IBV strains could not be propagated in HeLa cells, a human cell line (Brown & Cunningham, 1971;Otsuki et al, 1979). In this report, we have investigated potential factors that might block IBV infection of HeLa cells.…”

“…Although it has been isolated from other avian species reared near domestic fowl, and there is a very similar virus in pheasants (Cavanagh et al, 2002), the chicken is thought to be the primary natural host. Furthermore, most IBV strains usually grow poorly in cell culture except in primary chicken kidney cells (Cunningham & Spring, 1965;Otsuki et al, 1979). However, isolation of IBV from species other than the chicken has shown that the host range of IBV has extended beyond the chicken, like other coronaviruses such as bovine coronavirus and severe acute respiratory syndrome-coronavirus (Cavanagh, 2005).…”