T cell immune responses towards plasmodium falciparum and Schistosoma mansoni co-infection in school going children along lake Victoria shoreline, Mayuge district

Abstract

Background: T cell immune response is a major component of adaptive immune response system. Immune memory is developed when T helper cells are involved, both Plasmodium falciparum and Schistosoma mansoni infections initiate T helper immune responses, which can be categorized into Th1, Th2, and Th17 immune response based on unique cytokine(s) produced by the T helper subpopulations. Objectives: The study documented the T helper subpopulation(s) in P. falciparum and S. mansoni during independent and co-infection. Methodology: Kato Katz technique and circulating cathodic antigen test were performed for S. mansoni screening whereas thick and thin blood smears techniques were performed for P. falciparum screening. And the ex vivo T helper phenotyping was done using the human Th1/Th2/Th17 phenotyping kit through utilizing specific signature marker cytokines and surface marker; IFN-γ, IL-4, IL-17A and CD4 respectively. The PBMCs were nonspecifically stimulated using PMA/Neomycin after PBMCs treated with protein transport inhibitor to enhance cytokine production and build up in Golgi apparatus. Fixed, permeabilized, intracellular stained with fluorescent attached monoclonal antibodies of IFN-γ, IL-4 and IL-17A, surface stained with fluorescent attached monoclonal antibody of CD4 and flow cytometric analysis done. Data analysis done using Flow Jo version 10 and Graph pad Prism 6 Software, and statistical significance (P<0.05) was determined using Wilcoxon Signed Rank test, Whitney U test and F-test. Results: There was up regulated Th1 T helper subpopulation in independent P. falciparum compared to no infection group , whereas suboptimal T helper immune responses in independent S. mansoni with significant down regulated Th1 (Z= -1.425, p = 0.0313), down regulated Th2 and Th17 compared to no infection group. And suboptimal T helper immune responses in co-infection with significantly down regulated Th1 (Z= -3.260, p = 0.0273) and Th2 (Z= -1.180, p = 0.0078), and down regulated Th17 compared to independent P. falciparum. Conclusions: The study revealed that a S. mansoni infection is a major contributor of reduced effective T helper immune responses against P. falciparum during the co-infection.