DYNAMICS OF AVIAN INFLAMMATORY RESPONSE TO SALMONELLA-IMMUNE LYMPHOKINES - CHANGES IN AVIAN BLOOD LEUKOCYTE POPULATIONS

Investigations in our laboratories have indicated that an increased re sistance to SE organ infectivity in chicks was conferred by the immuno prophylactic administration of SE-immune lymphokines (SE-ILK). This re sistance was associated with an increase in the lamina propria thickne ss due to a marked infiltration of inflammatory polymorphonuclear cell s (PMNs). In the present study, we determined whether the hematologica l profile of SE-ILK-treated chicks might reflect changes that are asso ciated with the protection against organ invasion by SE, As protection has been observed in previous studies within 24 h of SE-ILK administr ation, we evaluated alterations in the circulating leukocyte profile i n 1-day-old Leghorn chicks during this time period. We also determined whether the alterations in the peripheral blood leukocytes correlated with the increased protection against SE organ invasion induced by th e SE-ILK. Within 4 h after an intraperitoneal injection of SE-ILK and challenge with SE, the number of circulating leukocytes increased sign ificantly (P < 0.05) from all of the other treatment groups. The numbe r of circulating PMNs was found to account for more than 80% of the in crease in the number of circulating leukocytes. Using correlation anal ysis, we found a strong association between the number of circulating PMNs and the protection induced by SE-ILK against SE organ invasion. T hese studies associate the expansion of the available pool of circulat ing PMNs and the expression of innate resistance to organ invasion by SE.