Vella A T, Hulsebosch M D, Pearce E J
Department of Microbiology, Immunology and Parasitology, Cornell University, Ithaca NY 14853.
J Immunol. 1992 Sep 1;149(5):1714-22.
Schistosoma mansoni eggs are potent inducers of biased Th2-like immune responses. Using a model system where mice are immunized with isolated schistosome eggs, we demonstrate that CD44 expression, up-regulation of which has been linked to Th cell development, is increased on Th2 cells. We also investigate the functional properties of CD44-lo Th cells recovered from the overtly Th2 environment constituted by lymph nodes draining sites of egg deposition. Production of high levels of IL-4, IL-5, and IL-10 by Th cells responding to egg Ag is shown to be the property of a subpopulation expressing CD44-hi. This population of Th cells cosegregates with a blasting subpopulation expressing more IL-4R (but similar amounts of IL-2R) than Th cells from normal mice. These results indicate that mature Th2 cells responding to schistosome eggs are CD44-hi and suggest that they use IL-4 as a growth factor. In contrast, CD44-lo cells sorted from lymph node populations responding to eggs are able to produce small amounts of IL-4 and IL-2, but no IL-5 or IL-10. This is surprising, because low expression of CD44 is considered a characteristic of Th cell naivite and concomitant ability to produce only IL-2. Thus, in lymph nodes responding to schistosome eggs, potential for Th2 subset differentiation is evident within the CD44-lo precursor Th subpopulation.
曼氏血吸虫卵是偏向性Th2样免疫反应的强效诱导剂。利用小鼠用分离出的血吸虫卵进行免疫的模型系统，我们证明，与Th细胞发育相关的CD44表达上调在Th2细胞上增加。我们还研究了从由虫卵沉积引流部位的淋巴结构成的明显Th2环境中回收的CD44低表达Th细胞的功能特性。对虫卵抗原作出反应的Th细胞产生高水平的IL-4、IL-5和IL-10被证明是表达CD44高的亚群的特性。这群Th细胞与一个增殖亚群共分离，该增殖亚群比正常小鼠的Th细胞表达更多的IL-4R（但IL-2R量相似）。这些结果表明，对血吸虫卵作出反应的成熟Th2细胞是CD44高表达的，并表明它们将IL-4用作生长因子。相反，从对虫卵作出反应的淋巴结群体中分选出来的CD44低表达细胞能够产生少量的IL-4和IL-2，但不产生IL-5或IL-10。这令人惊讶，因为CD44的低表达被认为是Th细胞幼稚的特征以及仅产生IL-2的伴随能力。因此，在对血吸虫卵作出反应的淋巴结中，CD44低表达前体Th亚群内Th2亚群分化的潜力是明显的。
