IMMUNE SUPPRESSION IN CALVES WITH BOVINE IMMUNODEFICIENCY VIRUS

The present study was designed to evaluate the effect of bovine immuno deficiency virus (BIV) infection on immune functions and possible inte ractions between BIV and other bovine viruses in calves, Ten calves we re inoculated intravenously with BIV, and five served as controls. An increased lymphocyte proliferation to BN gag protein was demonstrated 2 to 6 weeks after BIV inoculation (P < 0.05). Lymphocyte subset diffe rentiation revealed a decreased CD4/CD8 ratio (P < 0.05) during weeks 2 to 7, suggesting a possible immune dysfunction in BIV-infected calve s. When the calves were inoculated with bovine herpesvirus type 1 (BHV -1), the antibody response to BHV-1 in BN-infected calves was delayed and the antibody titers were significantly lower (P < 0.05). Injection of bovine viral diarrhea virus vaccine also elicited a lower neutrali zing antibody response in BIV-infected calves. The results indicated t hat immune suppression occurred in BIV-infected calves.