The vitamin D receptor and inducible nitric oxide synthase associated pathways in the development of acquired resistance to Cooperia oncophora infection in cattle

Cooperia oncophora is an economically important gastrointestinal nematode in ruminants. Acquired resistance to Cooperia oncophora infection in cattle develops rapidly as a result of prior infections. Naïve cattle, when given a primary infection of high-dose infective L3 larvae, develop a strong immunity to subsequent reinfection. Compared to primary infection, reinfection resulted in a marked reduction in worm establishment. In order to understand molecular mechanisms underlying the development of acquired resistance, we characterized the transcriptomic responses of the bovine small intestine to a primary infection and reinfection. A total of 23 pathways were significantly impacted during infection. The vitamin D receptor activation was strongly induced only during reinfection, suggesting that this pathway may play an important role in the development of acquired resistance via its potential roles in immune regulation and intestinal mucosal integrity maintenance. The expression of inducible nitric oxide synthase (NOS2) was strongly induced during reinfection but now during primary infection. As a result, several canonical pathways associated with NOS2 were impacted. The genes involved in eicosanoid synthesis, including prostaglandin synthase 2 (PTGS2 or COX2), remained largely unchanged during infection. The rapid development of acquired resistance may help explain the lack of relative pathogenicity by Cooperia oncophora infection in cattle. Our findings will undoubtedly facilitate understanding of molecular mechanisms underlying the development of acquired resistance, which could have an important implication in vaccine design. The transcriptomic profiles of the bovine small intestine in response to both a primary infection and a drug-attenuated reinfection were compared. The data were analyzed using the same condition and procedure. The gene expression profiles of calves 14 days after a primary Cooperia oncophora infection and a drug-attenuated reinfection were compared to their respective age-matched controls (naive controls and drug-drenched worm-free controls)