A Whole Blood Method for Assessing the Innate Immune Response in Chickens

Innate immunity is considered the first line of immune defense and is typically an unmeasured response. Here we report a method for evaluating the innate immune response in chickens by using whole blood which has been activated by lipopolysaccharide (LPS) to induce IL-6 release by innate immune cells. It was found that a 24-h LPS activation time interval was the optimum time interval for inducing the IL-6 response. An activation index, defined as the PBS activated control response subtracted from the LPS activated response and then divided by the PBS activated control response and expressed as a percentage, was useful for demonstrating and comparing the magnitude of the innate immune response. Results indicated that there was wide variation between the IL-6 response between individual birds although statistically significant results were obtained for all individual birds at the 24-h activation time interval. The activation indices from all birds were greatest at the 24-h activation time interval. Statistically significant results were achieved when all the data from all birds at the 24-h activation time interval were combined. The cells responsible for the IL-6 response were identified as the peripheral blood monocytes.