Differential effects of human and porcine interleukin 2 on natural killing (NK) activity of newborn piglets and adult pigs lymphocytes.

The in vitro effects of human or porcine Interleukin 2 (IL2) on Natural Killing (NK) activity were studied with blood lymphocytes of newborn piglets and of adult pigs. Large volumes of porcine IL2 were prepared by PHA stimulation of irradiated mesenteric lymph node cells and, following purification by gel-filtration chromatography, the apparent molecular weight of IL2 was 15,000 Da. Purified human and porcine IL2 as well as recombinant human IL2 were found to increase markedly NK activity of lymphocytes derived from adult animals. However, although newborn piglets-derived lymphocytes are sensitive to crude porcine IL2 supernatants (and to Interferon alpha as previously shown) their low NK activity is unaffected by purified IL2. These data suggest therefore the existence of differences in the ontogenic development of the lymphokines responsiveness of porcine NK cells.