Innate Lymphocytes In Young Mice Promote Protection Against Plasmodium Chabaudi Infection

Understanding the immune response to malaria, especially in children under five, is limited due to the lack of a reliable animal model to study the pathogenesis of the disease. By utilizing a newly developed young rodent model in our lab, we have observed that both splenocytes and purified CD4+ T cells from 8-week adult mice proliferate faster than day 15 old young mice when stimulated with a plate bound anti-CD3 and CD28 in vitro. Using adoptive transfer technique, we show that both pup and adult cells protect immunocompromised RAG1 knockout (RAG1KO) mice from death. To better understand the responsive and protective cell populations in the splenocytes from the young mice, we adoptively transferred splenocytes from both pups and adult mice into RAG1KO mice and infected the recipients with P. chabaudi. We observed higher numbers and proportions of innate lymphocytes including gamma delta (yd) T cells and natural killer (NK) cells in the pup splenocyte recipients when compared to adult counterparts on day 9 post-infection. In contrast, there were significantly higher proportions of macrophages in the adult splenocyte recipients. Taken together, our findings suggest that pup splenocytes are enriched with innate lymphocytes that may promote protection against P. chabaudi infection.