Characterisation of lymphocyte populations in African buffalo (Syncerus caffer) and waterbuck (Kobus defassa) with workshop monoclonal antibodies

In order to measure different lymphocyte populations in buffalo (Syncerus caffer) and waterbuck (Kobus defassa), we analysed the monoclonal antibodies from the 1st International Workshop on Leukocyte Antigens in Cattle, Sheep and Goats for suitable cross-reactive reagents. Peripheral blood mononuclear cells from three buffalo and three waterbuck were tested with the whole panel of monoclonal antibodies (mAbs) together with some additional antibodies against MHC and Ig. In some clusters almost all antibodies cross-reacted (CD2, CD8), in others almost none cross-reacted (CD4, CD5) and in cluster CD6, mAbs only reacted with buffalo but not waterbuck. Double staining experiments were performed on buffalo PBM with the cross-reacting antibodies, to confirm that they detected similar cell populations as in bovine PBM. This was shown with reagents against CD2, CD4, CD6, CD8, CD11, WC1, WC3 and Ig. The molecular weights of the buffalo antigens correlated well with those of the homologous cattle antigens. In the CD5 cluster, only one mAb reacted with the two wild species, and defined an unusual CD2+ CD5- cell population in buffalo. Also mAbs cross-reacting with buffalo MHC class II detected unusual expression on resting T cells. From the results presented, it is clear that the workshop panel contains mAbs against the most important T and B cell antigens of buffalo and probably waterbuck, which will allow us to compare functional lymphocyte populations in cattle and wild ruminants.