Modulation of functional activities of chicken heterophils by recombinant chicken IFN-gamma

The objective of the present studies was to examine the in vitro effects of recombinant chicken interferon-gamma (rChIFN-gamma) on shape change, phago cytosis, and the oxidative/nonoxidative killing activities of day-old chick en heterophils, Heterophils (4 x 10(6)/ml) were incubated with various conc entrations of recombinant ChIFN-gamma from both Escherichia coil and transf ected Cos cells for 2 h at 39 degreesC, The incubation of the neonatal hete rophils with rChIFN-gamma resulted in significantly greater numbers of cell s with membrane shape change when compared with the mock-treated heterophil s, Both Cos cell-derived and E, coli-derived ChIFN-gamma significantly incr eased (p < 0.01) the phagocytosis of opsonized or nonopsonized Salmonella e nteritidis by the neonatal heterophils in a concentration-dependent manner. Incubation with ChIFN-<gamma> induced no direct stimulation of the respira tory burst by the chicken heterophils but did prime the heterophils for a s ignificantly strengthened respiratory burst to subsequent stimulation with opsonized zymosan (OZ), Lastly, incubation of the heterophils with ChIFN-ga mma primed the cells for a significant increase in the release of beta -D-g lucuronidase following stimulation with OZ. These results show that neonata l avian heterophils can respond to cytokine modulation with enhanced functi onal competence, suggesting that ChIFN-gamma can enhance the immune compete nce of the innate defenses of chickens during the first week of life.