The parasitic infection is still a severe public health problem in developing countries, which threatens people's health and social development. With the advances of molecular biology and immunology, more and more insights have been reached on the immunity and immunopathogenesis to parasitic infections. CD4+ T cells play a central role in the host's immunosurveillance and immunoregulation. Traditionally, naive CD4+ T cells are considered to be able to differentiate into Th1 and Th2 cell subsets both in vivo and in vitro. These Th1 and Th2 cells secret diverse cytokine profiles to exert different functions. Later, two new subsets of CD4+ T cells, Th17 and Treg cells, have been discovered. They are completely different from traditional Th1 and Th2 cells with independent differentiation and regulation mechanism. Ample studies suggest that Treg and Th17 cells play a key role in a variety of parasitic diseases. Furthermore, Treg and Th17 cells have been got increasing attention for their involvement in the hygiene hypothesis. Based on the current advances of researches of Treg and Th17 cells, we make a brief review about immunomodulatory effects of these two subsets in parasitic infections as well as the hygiene hypothesis.
［摘要］ 寄生虫感染在发展中国家仍然是一个严重威胁人类健康、影响社会经济发展的公共卫生问题。近年来, 随着分 子生物学和免疫学等研究进展, 人们对寄生虫感染的免疫防御反应及免疫病理机制有了更多认识。CD4+T细胞在机体 免疫防御及免疫调节中发挥着非常重要的作用。传统上认为CD4+T细胞在体内外可分化成Th1、Th2两大细胞亚群, 它 们产生不同的细胞因子, 发挥不同功能。后来又发现了两种新的CD4+T 细胞亚群, 即Th17细胞和调节性T (Treg) 细胞。 它们具有与传统的Th1、Th2细胞完全不同的、独立的分化和调节机制。已有大量研究证实, Treg和Th17细胞在寄生虫病 的抗虫免疫及免疫病理机制中发挥着重要作用。此外, Th17和Treg细胞在寄生虫感染所诱导的卫生假说中的作用越来 越受到重视。本文根据当前国内外有关Treg和Th17细胞分化及功能的研究进展, 对Treg和Th17细胞在寄生虫感染及 卫生假说中的作用作一简要综述。.
Keywords: Hygiene hypothesis; Immunomodulation; Parasitic infection; Th17 cell; Treg cell.