Comparison of CD4 T cell response in Plasmodium falciparum and vivax malaria
Nalubega M., Soon MSF., Andrew D., Ortega-Pajares A., Canning J., Dooley N., Loughland JR., Engwerda C., Kenangalem E., Price RN., Minigo G., Anstey NM., Oyong DA., Boyle MJ.
Abstract Background Plasmodium falciparum and P. vivax are parasites responsible for most malaria cases globally. In areas where these species co-exist, individuals gain protection from P. vivax more rapidly, and important biological differences between species may impact the immune response. CD4 T cells are key drivers of immunity to malaria, both as effector and helper cells, with T-follicular helper (Tfh) cells having key roles in antibody development. Comparative studies on CD4 T cell responses between these species are limited. Methods We assessed CD4 T cells in adults with either P. falciparum or P. vivax malaria. Activation and proliferation of CD4 T cells were measured ex vivo, and functional capacity was determined by intracellular cytokine staining using flow cytometry. Results The phenotype, activation and proliferation of CD4 T cells and effector CD4 T cell subsets were comparable between species. However, within the peripheral (p)Tfh cell compartment, there was some evidence for species-dependent activation with relative increased pTfh1 cells in P. falciparum infection. Additionally, in P. falciparum, increased IL-10 production was detected, including within IL-21 producing CD4 T cells. Conclusion While activation and function of CD4 T cells in malaria are largely comparable, some species-dependent responses are detected within the pTfh cell compartment that may impact antibody development.