CD4+CD25hiFOXP3+ Cells in Cord Blood of Neonates Born from Filaria Infected Mother Are Negatively Associated with CD4+Tbet+ and CD4+RORγt+ T Cells

Background: Children who have been exposed in utero to maternal filarial infection are immunologically less responsive to filarial antigens, have less pathology, and are more susceptible to acquire infection than offspring of uninfected mothers. Moreover children from filaria infected mothers have been shown to be less responsive to vaccination as a consequence of an impairment of their immune response. However, it is not well known how in utero exposure to parasite antigens affects cellular immune responses. Methodology: Here, 30 pregnant women were examined for the presence of microfilaria of Loa loa and Mansonella perstans in peripheral blood. At delivery, cord blood mononuclear cells (CBMC) were obtained and the CD4(+)T cells were phenotyped by expression of the transcription factors Tbet, ROR gamma t, and FOXP3. Results: No significant difference was observed between newborns from infected versus uninfected mothers in the frequencies of total CD4(+)T cells and CD4(+)T cells subsets including CD4(+)Tbet(+), CD4(+)ROR gamma t(+) T and CD4(+)CD25(hi)FOXP3(+) T cells. However, there was a negative association between CD4(+)CD25(hi)FOXP3(+)T cells and CD4(+)Tbet(+) as well as CD4(+)ROR gamma t(+) T cells in the infected group only (B=-0.242, P=0.002; B=-0.178, P=0.013 respectively). Conclusion: Our results suggest that filarial infection during pregnancy leads to an expansion of functionally active regulatory T cells that keep TH1 and TH17 in check.