Evaluation of live feline immunodeficiency virus vaccines with modified antigenic properties.
Live-attenuated viruses have typically been generated from pathogenic viruses by genetic modifications that modified their replicative capacity. The present study investigated whether modification of the antigenic properties of live-attenuated viruses might improve upon the protection that such vaccines afford against lentivirus infection. In a previous study, random amino acid substitutions were introduced into the transmembrane envelope glycoprotein of the feline immunodeficiency virus (FIV), within a highly conserved domain (principal immunodominant domain) bearing immunodominant B-cell epitopes. Amongst a wide set of mutants, mutations that modified antibody specificity without abolishing infectivity ex vivo were selected. In the present study, two such mutants, TN14 and TN92, were evaluated for their replicative capacities and pathogenic properties in vivo in comparison with the parental virus, FIV 34TF10. No significant differences in viral load were observed between mutant and parental viruses. After 1 year of infection, all animals were subjected to a heterologous intraclade superinfection with a primary strain of FIV. Whilst both parental and modified viruses protected cats from high viral loads after superinfection, the TN92 virus afforded a higher degree of protection (P=0.0079). Such improvement in protection might correlate with a decrease in the immunogenicity of a B-cell epitope potentially involved in antibody enhancement of infection.
Broche-Pierre
Sophie
S
Génétique des Virus, Institut Cochin (INSERM U567, CNRS UMR8104), 22 rue Méchain, 75014 Paris, France.
Richardson
Jennifer
J
Génétique des Virus, Institut Cochin (INSERM U567, CNRS UMR8104), 22 rue Méchain, 75014 Paris, France.
Moraillon
Anne
A
UMR INRA-ENVA-AFSSA 1161 de Virologie, Ecole Nationale Vétérinaire d'Alfort (ENVA), 7 rue du Général de Gaulle, 94704 Maisons-Alfort, France.
Sonigo
Pierre
P
Génétique des Virus, Institut Cochin (INSERM U567, CNRS UMR8104), 22 rue Méchain, 75014 Paris, France.
D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D001483:Base Sequence; D002371:Cat Diseases / Q000276:immunology / Q000517:prevention & control* / Q000821:virology; D002415:Cats; D018985:Epitopes, B-Lymphocyte / Q000276:immunology; D015686:Gene Products, env / Q000008:administration & dosage / Q000235:genetics* / Q000276:immunology; D016089:Immunodeficiency Virus, Feline / Q000235:genetics / Q000276:immunology* / Q000472:pathogenicity; D016056:Immunodominant Epitopes / Q000276:immunology; D016180:Lentivirus Infections / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary* / Q000821:virology; D008969:Molecular Sequence Data; D014611:Vaccination; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000276:immunology*; D019444:Vaccines, DNA / Q000008:administration & dosage / Q000276:immunology; D014765:Viral Vaccines / Q000008:administration & dosage / Q000276:immunology*
D000914:Antibodies, Viral; D018985:Epitopes, B-Lymphocyte; D015686:Gene Products, env; D016056:Immunodominant Epitopes; D014613:Vaccines, Attenuated; D019444:Vaccines, DNA; D014765:Viral Vaccines