FREQUENCY OF INTERFERON-ALPHA-SECRETING BLOOD LEUKOCYTES IN IRRADIATED AND BONE-MARROW-GRAFTED PIGS

The effects of irradiation were studied on porcine interferon-alpha (I FN-alpha) secreting cells (IFN-alpha SC). IFN-alpha SC were characteri zed by an ELISPOT assay on non-adherent PBMC following incubation with the transmissible gastroenteritis coronavirus. In vitro irradiation o f PBMC was followed by a decrease in the number of IFN-alpha SC while IFN-gamma production and cell viability were not affected. These data indicate that porcine IFN-alpha SC are relatively radiosensitive. Inde ed, the frequency of blood IFN-alpha SC decreased markedly and rapidly after in vivo whole body or partial lymphoid irradiation. In addition , within several days of compatible bone-marrow engraftment in the irr adiated animals, the number of blood IFN-alpha SC returned to normal v alues. These data demonstrate that circulating porcine IFN-alpha SC ar e derived from bone-marrow progenitors.