Human recombinant interleukin-2 125 induced in vitro proliferation of equine, caprine, ovine, canine and feline peripheral blood lymphocytes

Abstract

Equine, caprine, ovine, canine and feline peripheral blood lymphocytes were evaluated in a short term dose-response study for their in vitro blastogenic responsiveness to human recombinant interleukin-2 125 (HrIL-2 125) alone or in combination with phytohemagglutinin-P, concanavalin-A, and pokeweed mitogen. HrIL-2 125 induced lymphocyte proliferation in all of the animals tested. The magnitude of the proliferative response varied among the species of animal tested. In all cases the proliferative response was dependent on the concentration of HrIL-2 125. HrIL-2 125 at a minimum concentration of 10 2 Cetus Units (CU)/ml produced a significant proliferative response in isolated horse, goat and sheep lymphocytes. In cat and dog lymphocytes, a concentration of 10 3 CU/ml was necessary to induce a significant proliferative response. Maximal lymphocyte proliferation was reached in horses and sheep at a concentration of 10 4 CU/ml of HrIL-2 125. In goats, cats, and dogs a maximum proliferative response was found to be at a concentration equal to or greater than 10 4 CU/ml of HrIL-2. Co-stimulation of lymphocytes with mitogens and submaximal concentrations of HrIL-2 125 (10 CU/ml) induced a synergistic proliferative response which in nearly all cases was significantly greater ( P < 0.05) than the arithmetic sum of the responses induced by the same concentration of the mitogens and HrIL-2 125 alone. The two exceptions were co-stimulation of feline lymphocytes with concanavalin-A and co-stimulation of canine lymphocytes with pokeweed mitogen.