LONGITUDINAL-STUDIES OF IMMUNE FUNCTION IN CATTLE EXPERIMENTALLY INFECTED WITH BOVINE IMMUNODEFICIENCY-LIKE VIRUS AND OR BOVINE LEUKEMIA-VIRUS/

The effects of single or dual infection with bovine immunodeficiency-l ike virus (BIV) and/or bovine leukemia virus (BLV) on bovine immune fu nction were examined over a 4 year period. Holstein calves were infect ed with BIV (four calves), BLV (five calves), BIV and BLV (five calves ), or sham inoculated (three calves). Lymphocyte blastogenesis to mito gens, seven tests of neutrophil function, and mononuclear cell subset analysis by flow cytometry (BoCD4, BoCD8, BoCD2, BoWC1, sIgM(+), and m onocytes) were performed at regular intervals to 49 months post-infect ion. These data were analyzed for main effects of each virus and inter action as a 2 x 2 factorial. BIV infected cattle had lower neutrophil antibody-dependent cell-mediated cytotoxicity and iodination responses during 2 of the 4 years post-infection (P < 0.05). BIV infection was not associated with any long-term significant changes in lymphocyte bl astogenesis to mitogens or changes in mononuclear cell subset numbers in blood. There was a tendency for animals infected with BIV alone to have decreased lymphocyte blastogenic responses to mitogens, but this was not statistically significant. BLV infection caused an increase in total mononuclear cells with no dramatic shift in the relative propor tions of the various subsets. Go-infection with BIV and BLV did not co nsistently cause a different response than either virus did individual ly. One BIV infected animal died of non-BLV lymphosarcoma 7 months aft er infection. All other animals had no unusual clinical signs. In summ ary, infection with BIV caused a significant, temporary decrease in ne utrophil function with no consistent statistically significant alterat ion in lymphocyte blastogenesis or mononuclear cell numbers during the first 4 years after infection. BLV infection caused an increase in ly mphocyte numbers, and there appeared to be no synergism between the vi ruses. (C) 1997 Elsevier Science B.V.