Interaction of dexamethasone and Salmonella enteritidis immune lymphokines on Salmonella enteritidis organ invasion and in vitro polymorphonuclear leukocyte function.

We used an anti-inflammatory dose of dexamethasone (DEX) and Salmonella enteritidis (SE)-immune lymphokines (ILK) followed by oral SE challenge to chicks to determine the effects of these treatments on SE organ invasion and in vitro function of PMNs derived from peripheral blood. Endpoints included percent protection against SE organ invasion, numbers of peripheral blood PMNs, and in vitro PMN adherence, chemotaxis, and SE killing. SE organ invasion was significantly reduced in chicks treated with either ILK alone or DEX + ILK compared to controls. Chicks treated with either DEX alone or DEX + ILK responded with a significant increase in numbers of peripheral blood PMNs as compared to controls, while numbers of PMNs in the peripheral blood from chicks treated with ILK alone were not significantly increased. PMN adherence and percent SE killing by PMNs derived from chicks treated with either ILK alone or DEX + ILK were significantly increased compared to controls. Chemotaxis of PMNs derived from chicks treated with either ILK alone or DEX alone significantly increased 2-fold over control levels. Interestingly, chemotaxis of PMNs derived from chicks that received DEX + ILK was similar to controls. Generally, ILK abated the anti-inflammatory effects of DEX on PMNs in these assays, except for chemotaxis. We interpret these data to suggest that ILK may confer protection to chicks against the early phase of SE organ invasion by inducing an inflammatory response predominated by activated PMNs.