Partial regulatory T cell depletion prior to schistosomiasis vaccination does not enhance the protection.
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.
Department of Pathogen Biology and Immunology, School of Medicine, Anhui University of Science and Technology, Huainan, Anhui, China. wangxxff1023@yahoo.com.cn
Xuefeng
X
Wang
Fan
F
Liu
Sha
S
Zhou
Zhipeng
Z
Xu
Jason
J
Hoellwarth
Xiaojun
X
Chen
Lei
L
He
Rongbo
R
Zhang
Feng
F
Liu
Jun
J
Wang
Chuan
C
Su
D000818:Animals; D005260:Female; D005982:Glutathione Transferase / Q000276:immunology; D016753:Interleukin-10 / Q000276:immunology; D053645:Interleukin-2 Receptor alpha Subunit / Q000276:immunology*; D008212:Lymphocyte Depletion; D051379:Mice; D008810:Mice, Inbred C57BL; D012549:Schistosoma japonicum / Q000276:immunology; D012554:Schistosomiasis japonica / Q000276:immunology / Q000517:prevention & control*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D014611:Vaccination / Q000379:methods*
C508018:Il2ra protein, mouse; D053645:Interleukin-2 Receptor alpha Subunit; D016753:Interleukin-10; D005982:Glutathione Transferase