Herpesviruses Provide Helper Functions for Avian Adeno-associated Parvovirus

Abstract

SUMMARYThe avian herpesviruses infectious laryngotracheitis virus (ILTV) and herpesvirus of turkeys (HVT), as well as the mammalian herpesvirus pseudorabies virus (PRV) were able to provide complete helper activity for the production of infectious avian adenoassociated virus (AAAV) in chicken cells. The presence of AAAV in the infected chicken cell reduced the multiplication of HVT. ILTV or PRV, however, were not affected if used as helper viruses. Infectious AAAV was determined by an indirect immunofluorescence assay and infectious herpesvirus by plaque assays.Avian adeno-associated virus (AAAV) is a defective parvovirus which grows efficiently only in chicken cells co-infected with avian adenovirus (Yates et al., 1973;Pronovost et al., 1979). This report investigates whether or not other avian viruses can provide the helper function required for active multiplication of AAAV in chicken cells. We demonstrate that two avian herpesviruses, infectious laryngotracheitis virus (ILTV) and herpesvirus of turkeys (HVT), as well as pseudorabies virus (PRV), a herpesvirus of mammalian origin, provide complete helper activity for AAAV. A helper activity of human herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) for human AAV has been demonstrated (Buller et al., 1981). We also show that the growth of HVT is reduced in chicken cells co-infected with HVT and AAAV. However, there is no inhibitory effect on the multiplication of the helper virus if PRV or ILTV is used as helper.The AAAV strain ATCC VR-865 was propagated in embryonated chicken eggs (VALO, Cuxhaven, F.R.G.) by co-infection with fowl adenovirus serotype l (CELO virus) and prepurified by 1,1,2-trichlorotrifluoroethane treatment, followed by centrifugation in one discontinuous and two CsC1 equilibrium density gradients. The infectious AAAV particles which band in CsC1 at a density of 1.39 to 1.40 g/ml were collected. The remaining CELO virus in this AAAV preparation was removed by immunoprecipitation using rabbit anti-CELO virus serum and Protein A-Sepharose (Bauer & Monreal, 1985). Serum proteins in the purified AAAV were removed by an additional equilibrium density gradient. The final virus suspension was dialysed against cell culture Medium 199 with Earle's salts.The non-pathogenic ILTV strain ASL (Gelenczei & Marty, 1964) was plaque-purified three times and propagated in primary chicken kidney cells (CKC). The FC 126 strain of HVT (Witter et al., 1970) was obtained as a live vaccine against Marek's disease from E. Vielitz (TAD, Cuxhaven, F.R.G.). The lyophilized virus material was dissolved in SPGA stabilizer, pH 6.5, containing 0.218 M-sucrose, 0'0038 M-monopotassium phosphate, 0.0072 M-dipotassium phosphate, 0.0049 M-monosodium glutamate and 1 ~ bovine serum albumin (Calnek et al., 1970). The DEK strain of PRV (kindly provided by H. Ludwig, Berlin, F.R.G.) was plaquepurified three times and propagated in secondary chicken embryo fibroblasts (CEF).To study the growth cycle of AAAV with ILTV as helper virus and the influence of AAAV on the multiplication ...

Parvovirus Gene Regulation

“…This may simply be a reflection of the very lytic nature of HSV infection. Virion AAV has been reported to inhibit the replication of helper herpesvirus of turkeys in chicken fibroblasts (Bauer & Monreal, 1986).…”

Identification and characterization of an avian adenovirus isolated from a ‘spiking mortality syndrome’ field outbreak in broilers on the Delmarva Peninsula, USA

“…The virus strains S90, UF71 and SR48 were propagated in primary cultures of chick kidney cells (CKC) obtained from 14-to 28-day old SPF chicks and prepared according to Bauer & Monreal (1986). Briefly, infected cell cultures were maintained at 38°C for 24 to 72 h in 7% carbon dioxide until overall cytopathic effects were seen.…”

Avian adeno‐associated virus (AAAV) and fowl adenoviruses (FAV): Studies of viral interactions in chicken cell cultures

“…Using the avian herpesviruses, infectious laryngotracheitis virus (ILTV) and herpesvirus of turkeys (HVT) as helpers no differences in the growth properties of helper virus and AAAV are detectable (Bauer and Monreal, 1986).…”

“…3- (Bauer and Monreal, 1986). Briefly, CKC monolayers were grown in plastic dishes containing two glass coverslips and infected with 0.2 ml of serial dilutions of the virus samples and 0.1 ml CELO virus (m.o.i.…”

“…Avian adeno-associated virus (AAAV) is widely distributed in poultry flocks without any evidence of pathological manifestations (Yates et al, 1976;Schwarzmaier era/., 1984), Efficient multiplication of this defective parvovirus requires chicken cells coinfected with either avian adenovirus (Yates et al, 1973) or avian herpesvirus (Bauer and Monreal, 1986). In addition to the helper function of avian adenovirus, the inhibitory effect of AAAV on the growth of the helper virus plays an essential role in the biological interactions between both virus species.…”