Mucosal Humoral Immunity to Experimental Salmonella enteritidis Infection in the Chicken Crop

SUMMARY. In this report, we show that chickens, infected with Salmonella enteritidis (SE) by oral gavage, produce secretory immunoglobulin As (sIgAs) that specifically bind to numerous SE antigens. Chickens infected with SE showed strong sIgA response against flagella in both bile and crop. The optical density values of enzyme-linked immunosorbent assay (ELISA) tests in positive bile and crop were 1.17 and 0.38, respectively, and were significantly different from those of negative samples. Western immunoblotting revealed that ∼13.5-, ∼56-, ∼62-, ∼80-, and ∼143-kD polypeptides were immunodominant proteins in bile, whereas ∼56-, ∼62-, and ∼80-kD polypeptides were found to be strong antigens in crop. These results indicate that the crop may function as another site for mucosal immunity, and the SE flagella-based ELISA of crop samples can provide a useful screening test of SE exposure in chickens.