Evaluation of the Expression of IFN-γ, IL-4, IL-17, and IL-22 Cytokines in Birds Immunized with a Recombinant Chimeric Vaccine Containing Alpha Toxin, NetB, and ZMP against Necrotic Enteritis

Necrotic enteritis (NE), an infection of the gastrointestinal tract of birds, is a major concern of the poultry industry due to its huge economic losses. The disease is caused by the Gram-positive bacterium Clostridium perfringens (C. perfringens). Due to the ban on antibiotic usage in the poultry industry, the incidence of NE has increased significantly in recent years. We have previously shown that immunization of chickens with a subunit chimeric antigen composed of the most effective C. perfringens toxins in NE pathogenesis (alpha toxin, B-like toxin (NetB), and zinc metallopeptidase (ZMP)) can protect birds against this disease. In the present study, the chickens were subcutaneously immunized by the recombinant protein. Then, the expression profile of cytokines in immunized birds was evaluated. For this purpose, following the immunization regimen, samples were taken from the intestines of the birds, mRNAs were extracted and the expression of four different cytokines (IFN-γ, IL-4, IL-17, and IL-22) was investigated using quantitative real-time PCR. The mentioned cytokines are representatives of helper T lymphocytes and have roles in several immune system activities, such as cellular, humoral, and mucosal immunity responses, as well as inflammation. According to the results of the cytokine assay, subcutaneously-administered recombinant protein elicited humoral and cellular immune systems but it could not stimulate the mucosal immune system. The candidate vaccine elicited the immune system so that the differences between the adjuvant recombinant protein (Adj-rNAM group) and the control group were significant (p <0.001). The results, in addition to our previous study outputs, indicate that our strategy, after completing adequate investigations, can provide an alternative solution to using antibiotics in NE treatment.