Reactivity of monoclonal antibodies with bovine blood mononuclear cells activated by mitogens and superantigens

Monoclonal antibodies forming seven preliminary clusters in the third ruminant CD workshop (PC15, 16b, 16c, 20b, 26b, 26c and 30) were analysed by flow cytometry upon reaction with in vitro stimulated bovine mononuclear cells. Concanavalin A (Con A), pokeweed mitogen (PWM) and three Staphylococcus aureus enterotoxins (superantigens SEA, SEB and SEC2) were used as stimulating agents. The mAbs in PC15, 16c, and 26b reacted uniformly irrespective of the stimulating agent, in contrast to clusters PC16b, 20b, 26c and 30, which could be subgrouped according to differential reaction pattern depending on mitogen or superantigen stimulation. The mAbs CC28 and CACT114A seem to detect an antigen preferably induced by superantigens. MAb GB16A was shown to react strongly with Con A. Depending on the activation antigen, its time course of expression was either the same upon superantigen stimulation as that for mitogen-stimulated cells or slightly delayed.