Partial dissociation of subgroup C phenotype and in vivo behaviour in feline leukaemia viruses with chimeric envelope genes

Rigby, M. A., Rojko, J. L., Stewart, M. A., Kociba, G. J., Cheney, C. M., Rezanka, L. J., Mathes, L. E., Hartke, J. R., Jarrett, O. and Neil, J.C. (1992) Partial dissociation of subgroup C phenotype and in vivo behaviour in feline leukaemia viruses with chimeric envelope genes. Journal of General Virology, 73(11), pp. 2839-2847. (doi:10.1099/0022-1317-73-11-2839) (PMID:1331290)

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Abstract

Feline leukaemia viruses (FeLVs) are classified into subgroups A, B and C by their use of different host cell receptors on feline cells, a phenotype which is determined by the viral envelope. FeLV-A is the ubiquitous, highly infectious form of FeLV, and FeLV-C isolates are rare variants which are invariably isolated along with FeLV-A. The FeLV-C isolates share the capacity to induce acute non-regenerative anaemia and the prototype, FeLV-C/Sarma, has strongly age-restricted infectivity for cats. The FeLV-C/Sarma env sequence is closely related to that of common, weakly pathogenic FeLV-A isolates. We now show by construction of chimeric viruses that the receptor specificity of FeLV-A/Glasgow-1 virus can be converted to that of FeLV-C by exchange of a single env variable domain, Vr1, which differs by a three codon deletion and nine adjacent substitutions. Attempts to dissect this region further by directed mutagenesis resulted in disabled proviruses. Sequence analysis of independent natural FeLV-C isolates showed that they have unique Vr1 sequences which are distinct from the conserved FeLV-A pattern. The chimeric viruses which acquired the host range and subgroup properties of FeLV-C retained certain FeLV-A-like properties in that they were non-cytopathogenic in 3201B feline T cells and readily induced viraemia in weanling animals. They also induced a profound anaemia in neonates which had a more prolonged course than that induced by FeLV-C/Sarma and which was macrocytic rather than non-regenerative in nature. Although receptor specificity and a major determinant of pathogenicity segregate with Vr1, it appears that sequences elsewhere in the genome influence infectivity and pathogenicity independently of the subgroup phenotype.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Neil, Professor James
Authors: Rigby, M. A., Rojko, J. L., Stewart, M. A., Kociba, G. J., Cheney, C. M., Rezanka, L. J., Mathes, L. E., Hartke, J. R., Jarrett, O., and Neil, J.C.
College/School:College of Medical Veterinary and Life Sciences > Institute of Infection Immunity and Inflammation
Journal Name:Journal of General Virology
ISSN:0022-1317
ISSN (Online):1465-2099
Published Online:01 November 1992

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