IL15 and toxoplasmosis: In this study, codelivery both IL-21 and IL-15 as an adjuvant in DNA vaccines could significantly enhance the humoral and Th1-driven antigen-specific T helper immune responses induced by pVAX-CDPK1, facilitating protective immunity against toxoplasmosis in the mice model, which is was consistent with the results of previous studies that used both IL-21 and IL-15 as an adjuvant in DNA vaccines [19, 20].