Fine specificity of equine infectious anaemia virus gp90-specific antibodies associated with protective and enhancing immune responses in experimentally infected and immunized ponies

Equine infectious anaemia virus (EIAV) provides a model for examining the natural immunological control of a persistent lentivirus infection and for evaluating the efficacy of various vaccine strategies. As an initial characterization of antibody responses associated with protective or enhancing immune responses elicited by experimental infections or vaccinations, we have utilized synthetic peptide ELISA to characterize the fine specificity of antibodies to linear determinants of the EIAV surface glycoprotein, gp90. The data indicated that serum antibodies associated with protective or enhancing immune responses differed quantitatively and qualitatively in their pattern of reactivity to gp90 peptides. Protective and enhancing EIAV vaccines could also be distinguished by their ability to evoke anamnestic antibody responses to gp90 peptides. These studies demonstrate for the first time definitive differences in the specificity of protective and enhancing antibody responses to EIAV and emphasize the importance of using native viral glycoprotein immunogens in lentivirus vaccines.