Salafsky B, Fusco A C
Department of Biomedical Science, University of Illinois College of Medicine, Rockford.
Exp Parasitol. 1987 Dec;64(3):361-7. doi: 10.1016/0014-4894(87)90048-8.
We have determined that developing schistosomulae and adults of Schistosoma mansoni synthesize a wide range of eicosanoids when stimulated with linoleic acid, an essential fatty acid. Developing schistosomulae secrete 64%, while adults secrete over 80% of synthesized eicosanoids. On a per milligram soluble protein basis, eicosanoid secretion is ordered as follows: adult females greater than adult males much much greater than developing schistosomulae. Together one mature adult worm pair secreted approximately 4.36 micrograms prostaglandin E, 3.41 micrograms leukotriene B4, and 15.13 micrograms 5-hydroxyeicosatetraenoic acid (HETE) as determined by radioimmunoassay (RIA). High-performance liquid chromatography (HPLC) results have determined that 15-HETE is the major HETE species secreted by adults and developing schistosomulae. The immunosuppressant roles of 15-HETE, PGE, and LTB4 are discussed in relation to a possible mechanism for S. mansoni to evade the host immune system. Adults and schistosomules of S. mansoni have evolved rather sophisticated mechanisms for evading the host immune response. These include both host antigen acquisition and antigen shedding. In addition, young schistosomes have an as yet unidentified intrinsic defense mechanism against the host immune system. We postulate that part of the defense mechanism in schistosomules and adults may involve secretion of immunosuppressant eicosanoid species.
我们已经确定，曼氏血吸虫发育中的童虫和成虫在受到必需脂肪酸亚油酸刺激时会合成多种类二十烷酸。发育中的童虫分泌合成的类二十烷酸的64%，而成虫分泌超过80%。以每毫克可溶性蛋白为基础，类二十烷酸的分泌情况如下：成年雌虫大于成年雄虫，远大于发育中的童虫。通过放射免疫测定（RIA）确定，一对成熟的成虫大约分泌4.36微克前列腺素E、3.41微克白三烯B4和15.13微克5-羟基二十碳四烯酸（HETE）。高效液相色谱（HPLC）结果已确定15-HETE是成虫和发育中的童虫分泌的主要HETE种类。讨论了15-HETE、PGE和LTB4的免疫抑制作用与曼氏血吸虫逃避宿主免疫系统的可能机制的关系。曼氏血吸虫的成虫和童虫已经进化出相当复杂的机制来逃避宿主的免疫反应。这些机制包括宿主抗原获取和抗原脱落。此外，年轻的血吸虫对宿主免疫系统有一种尚未确定的内在防御机制。我们推测，童虫和成虫的部分防御机制可能涉及免疫抑制类二十烷酸的分泌。
