Effects of chicken interferon-γ and interleukin-2 on cytokines related to Th1 cell differentiation in peripheral blood

Abstract

This paper aims to explore the effects of chicken interferon-γ (ChIFN-γ) and interleukin-2 (ChIL-2) on type 1 helper (Th1) T lymphocyte differentiation. To be specific, ChIFN-γ and ChIL-2 were first expressed in Escherichia coli competent cells and then purified by Ni-NTA affinity chromatography. Different concentration of ChIFN-γ and ChIL-2 were employed to stimulate the lymphocytes in chicken peripheral blood which had been activated by concanavalin A (Con A), and the mRNA levels of cytokines related to Th1 cell differentiation were detected by real-time quantitative PCR (RT-qPCR). The results showed that both ChIFN-γ and ChIL-2 can significantly up-regulate mRNA levels of cytokines related to Th1 cell differentiation and the optimal concentration was 12.5 μg/mL and 25.0 μg/mL, respectively. In addition, specific-pathogen-free (SPF) chickens were immunized with ChIL-2 or ChIFN-γ together with H9N2 vaccine, or H9N2 vaccine alone by oral administration or intramuscular injection, respectively. The mRNA levels of cytokines related to Th1 cell differentiation were detected after immunization. The results showed that ChIFN-γ and ChIL-2 significantly up-regulated the mRNA levels of cytokines related to Th1 cell differentiation induced by H9N2 vaccine compared with H9N2 vaccine alone, and that the intramuscular injection was better than oral administration. In this study, we verified that ChIFN-γ and ChIL-2 can significantly enhance mRNA levels of cytokines related to Th1 cell differentiation induced by ConA or H9N2 vaccine in vitro and in vivo. The results of this study can lay a theoretical basis for using ChIFN-γ and ChIL-2 as vaccine adjuvants.