Antigenic variation in the bovine ephemeral fever virus glycoprotein

Antigenic variation in the bovine ephemeral fever virus glycoprotein was demonstrated using monoclonal antibodies and comparing a particular passage level of the BB7721 strain with (1) other Australian isolates of BEF virus, (2) the Beijing 1 strain of BEF virus, isolated in China and (3) batches of the BB7721 strain with different passage histories. Escape mutants of BEF virus were selected from cell culture and suckling mice, by growing virus in the presence of neutralising monoclonal antibodies. Escape frequencies were calculated for 14 monoclonal antibodies and an epitope map constructed of antigenic sites on the BEF viral glycoprotein which induce the production of neutralising antibodies

Antigenic variation of the bovine ephemeral fever virus glycoprotein.

Abstract Antigenic variation in the bovine ephemeral fever virus glycoprotein was demonstrated using monoclonal antibodies and comparing a particular passage level of the BB7721 strain with (1) other Australian isolates of BEF virus, (2) the Beijing 1 strain of BEF virus, isolated in China and (3) batches of the BB7721 strain with different passage histories. Escape mutants of BEF virus were selected from cell culture and suckling mice, by growing virus in the presence of neutralising monoclonal antibodies. Escape frequencies were calculated for 14 monoclonal antibodies and an epitope map constructed of antigenic sites on the BEF viral glycoprotein which induce the production of neutralising antibodies

Whole Genomes of Chandipura Virus Isolates and Comparative Analysis with Other Rhabdoviruses

The Chandipura virus (CHPV) belonging to the Vesiculovirus genus and Rhabdoviridae family, has recently been associated with a number of encephalitis epidemics, with high mortality in children, in different parts of India. No full length genome sequences of CHPV isolates were available in GenBank and little is known about the molecular markers for pathogenesis. In the present study, we provide the complete genomic sequences of four isolates from epidemics during 2003–2007. These sequences along with the deduced sequence of the prototype isolate of 1965 were analysed using phylogeny, motif search, homology modeling and epitope prediction methods. Comparison with other rhaboviruses was also done for functional extrapolations. All CHPV isolates clustered with the Isfahan virus and maintained several functional motifs of other rhabdoviruses. A notable difference with the prototype vesiculovirus, Vesicular Stomatitis Virus was in the L-domain flanking sequences of the M protein that are known to be crucial for interaction with host proteins. With respect to the prototype isolate, significant additional mutations were acquired in the 2003–2007 isolates. Several mutations in G mapped onto probable antigenic sites. A mutation in N mapped onto regions crucial for N-N interaction and a putative T-cell epitope. A mutation in the Casein kinase II phosphorylation site in P may attribute to increased rates of phosphorylation. Gene junction comparison revealed changes in the M-G junction of all the epidemic isolates that may have implications on read-through and gene transcription levels. The study can form the basis for further experimental verification and provide additional insights into the virulence determinants of the CHPV

Homologous and heterologous antibody reactions in sera from cattle naturally infected with bovine ephemeral fever group viruses

Four viruses belonging to the bovine ephemeral fever (BEF) group have been isolated from bovine blood. Infection of cattle with BEF virus was associated with neutralizing antibody responses to BEF, Kimberley (KIM), Berrimah (BRH) and Adelaide River (ADE) viruses, with highest antibody titres to BEF and KIM viruses. Infection of one cow with KIM virus was associated with a homologous neutralizing antibody response and nil or minimal responses to the other three viruses. Infection of a steer with ADE virus was associated with a rise in neutralizing antibody levels to ADE virus and to KIM virus, but not to BEF or BRH viruses. Infection of a steer with BRH virus was associated with marked neutralizing antibody rises to BRH and BEF viruses and small rises to KIM and ADE viruses. An antibody rise to BEF virus did not necessarily indicate recent BEF virus infection, and should be considered of diagnostic value only when taken in conjunction with clinical signs of disease

The isolation and preliminary characterization of a rhabdovirus in Australia related to bovine ephemeral fever virus

CSIRO 368 virus was isolated from blood collected in the Northern Territory from a healthy cow and electron microscope studies showed that the isolate had rhabdovirus morphology. Fluorescent antibody studies and complement fixation tests related the virus to bovine ephemeral fever (BEF) virus. Neutralization tests in both suckling mice and Vero cells showed that the virus was not BEF virus. Antibodies to CSIRO 368 virus were found in cattle sera from northern and eastern Australia and Papua New Guinea. Antibodies were found in 16 out of 45 buffalo, some of which also had antibodies to BEF virus. In contrast, none of the 419 deer tested had antibodies to CSIRO 368 virus, although 142 of the same deer had antibodies to BEF virus. No antibodies to CSIRO 368 virus was detected in 16 goats, 54 horses, 10 pigs, 31 sheep, 25 kangaroos, of 14 human beings. Both CSIRO 368 and BEF virus were found to be sensitive to ether and chloroform, but were not affected by the DNA inhibitor 5-bromo-2'-deoxyuridine, showing that they probably had the same type of nucleic acid - namely RNA. CSIRO 368 was also shown to grow to higher titres in BHK21 cells than in Vero cells. Temperature sensitivity studies at -20, 4 and 37°C showed that the presence of foetal calf serum increased the survival time markedly at -20°C, but only slightly at 4 and 37°C. The virus survived the longest at -20°C in the presence of foetal calf serum

Isolation of a new rhabdovirus in Australia related to Tibrogargan virus

A virus isolated from the blood of a healthy steer and designated DPP53 was shown to have rhabdovirus morphology. Although DPP53 virus was antigenically related to Tibrogargan virus by reciprocal immunofluorescence and neutralization tests, the viruses were distinguishable by neutralization tests. DPP53 virus contained RNA and was sensitive to both ether and chloroform. The geographical distribution of neutralizing antibody to DPP53 virus in Australian cattle corresponded to the distribution of Culicoides brevitarsis indicating that this virus may be arthropod-borne with this midge as a possible vector. Antibody to DPP53 virus was detected in serum from cattle, buffalo, dogs and one horse, but not in serum from deer, pigs, humans or wallabies. Highest virus titres were obtained by growth in Vero and BHK21 cell cultures, but the virus could also be grown in Aedes albopictus cell cultures. Higher virus titres were obtained when the multiplicity of infection was low. The name advanced for DPP53 virus is 'Coastal Plains' virus