Porcine IL-12 plasmid as an adjuvant improves the cellular and humoral immune responses of DNA vaccine targeting transmissible gastroenteritis virus spike gene in a mouse model

LI, Xunliang; LI, Pengchong; CAO, Liyan; BAI, Yunyun; CHEN, Huijie; LIU, He; REN, Xiaofeng; LI, Guangxing

T lymphocytes are significant effectors of the immune response and are vital for the activation of T helper cells (Th), cytotoxic T cells (Tc), and effector T cells (Te) among others. These cells participate and induce cellular and humoral immune responses within most organisms. In the present study, T lymphocytes showed a significant change, and CD4 + and CD8 + lymphocytes significantly increased in the blood and spleen of mice from pVAX1-(TGEV-S1) plus pVAX1-(pIL-12) group; a significant difference was observed compared to other groups. These cells reflect the proliferation of lymphocytes stimulated with antigens at 14 and 28 dpi. Thus, these plasmids could stimulate the cellular immunity, while pIL-12 exerted a promotional effect. However, all groups showed a decrease in immune response at 42 dpi; this observation indicates that the animals were entering exhaustion or that the immune effect had worn-off in the absence of stimulation.