Partial Regulatory T Cell Depletion Prior to Schistosomiasis Vaccination Does Not Enhance the Protection

by Xuefeng Wang, Fan Liu, Sha Zhou, Zhipeng Xu, Jason Hoellwarth, Xiaojun Chen, Lei He, Rongbo Zhang, Feng Liu, Jun Wang, Chuan Su

CD4⁺CD25⁺ regulatory T cells (Tregs) do
not only influence self-antigen specific immune responses, but also dampen
the protective effect induced by a number of vaccines. The impact of CD4⁺CD25⁺
Tregs on vaccines against schistosomiasis, a neglected tropical disease that
is a major public health concern, however, has not been examined. In this
study, a DNA vaccine encoding a 26 kDa glutathione S-transferase of Schistosoma
japonicum (pVAX1-Sj26GST) was constructed and its potential effects
were evaluated by depleting CD25⁺ cells prior to pVAX1-Sj26GST
immunization. This work shows that removal of CD25⁺ cells
prior to immunization with the pVAX1-Sj26GST schistosomiasis DNA vaccine significantly
increases the proliferation of splenocytes and IgG levels. However, CD25⁺
cell-depleted mice immunized with pVAX1-Sj26GST show no improved protection
against S. japonicum. Furthermore, depletion of CD25⁺
cells causes an increase in both pro-inflammatory cytokines (e.g. IFN-γ,
GM-CSF and IL-4) and an anti-inflammatory cytokine (e.g. IL-10), with CD4⁺CD25^-
T cells being one of the major sources of both IFN-γ and IL-10. These
findings indicate that partial CD25⁺ cell depletion fails
to enhance the effectiveness of the schistosome vaccine, possibly due to IL-10
production by CD4⁺CD25^- T cells, or other cell
types, after CD25⁺ cell depletion during vaccination.

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Partial Regulatory T Cell Depletion Prior to Schistosomiasis Vaccination Does Not Enhance the Protection
Syndicated from:PLoS ONE

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