Distribution of Peripheral Memory T Follicular Helper Cells in Patients with Schistosomiasis Japonica.

Xian Song,Chuan Su,Jifeng Zhu,Feng Liu,Xin Jin,Sha Zhou,Yang Zhang,Zhipeng Xu,Maria Yazdanbakhsh,Wei Li,Xiaojun Chen,Lei Xu,Gengxin Chen

doi:10.1371/journal.pntd.0004015

Xian Song, Chuan Su + Show 11 more

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https://doi.org/10.1371/journal.pntd.0004015

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Abstract

BackgroundSchistosomiasis is a helminthic disease that affects more than 200 million people. An effective vaccine would be a major step towards eliminating the disease. Studies suggest that T follicular helper (Tfh) cells provide help to B cells to generate the long-term humoral immunity, which would be a crucial component of successful vaccines. Thus, understanding the biological characteristics of Tfh cells in patients with schistosomiasis, which has never been explored, is essential for vaccine design.Methodology/Principal FindingsIn this study, we investigated the biological characteristics of peripheral memory Tfh cells in schistosomiasis patients by flow cytometry. Our data showed that the frequencies of total and activated peripheral memory Tfh cells in patients were significantly increased during Schistosoma japonicum infection. Moreover, Tfh2 cells, which were reported to be a specific subpopulation to facilitate the generation of protective antibodies, were increased more greatly than other subpopulations of total peripheral memory Tfh cells in patients with schistosomiasis japonica. More importantly, our result showed significant correlations of the percentage of Tfh2 cells with both the frequency of plasma cells and the level of IgG antibody. In addition, our results showed that the percentage of T follicular regulatory (Tfr) cells was also increased in patients with schistosomiasis.Conclusions/SignificanceOur report is the first characterization of peripheral memory Tfh cells in schistosomasis patients, which not only provides potential targets to improve immune response to vaccination, but also is important for the development of vaccination strategies to control schistosomiasis.

Highlights

Schistosomiasis remains a major public health problem in many developing countries
Current control strategies are based on chemotherapy, but recurrent reinfection of people living in endemic areas makes researchers search for an effective vaccine to provide long-term protection against schistosomiasis
Considering it is well-known that T follicular helper (Tfh) cells are specialized effector CD4+ T cells that provide help for germinal center (GC) formation and induce germinal centers (GCs) B cells to develop protective antibody responses, understanding the biology of Tfh cells in schistosomiasis patients is fundamental for vaccine strategy development

Summary

Introduction

Schistosomiasis remains a major public health problem in many developing countries. Estimates place the current number of infections at approximately 200 million people, with another 600 million considered at risk [1]. Praziquantel remains highly effective in schistosomiasis treatment, it provides only short-term protection and does not block disease transmission or reinfection [2]. An effective vaccine against schistosome infection would be a major step towards eliminating this devastating and widespread tropical parasitic disease. An effective anti-schistosome vaccine would immensely reduce the morbidity associated with schistosomiasis through induced immune responses leading to decrease in parasite load and reduced egg production [4,5]. The generation of long-term humoral immunity is a crucial component of successful vaccines. Studies suggest that T follicular helper (Tfh) cells provide help to B cells to generate the long-term humoral immunity, which would be a crucial component of successful vaccines. Understanding the biological characteristics of Tfh cells in patients with schistosomiasis, which has never been explored, is essential for vaccine design

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