Elliott D E, Weinstock J V
Department of Medicine, University of Iowa, Iowa City 52242, USA.
Metabolism. 1996 Aug;45(8 Suppl 1):88-90. doi: 10.1016/s0026-0495(96)90093-1.
The role of somatostatin (SRIF) in controlling the granulomatous inflammatory response to infection with the parasite Schistosoma mansoni was explored in mice. The murine granulomas contain SRIF-14. Immunoreactive SRIF and prepro SRIF localize in the cytoplasmic granules of macrophages within the granulomas. The granulomas contain mRNA for prepro SRIF and are not innervated. The production of SRIF by the inflammatory cells appears to be inducible. The granulomas contain mRNA for the SRIF receptors sst2A and sst2B, which are expressed mainly on CD4- T lymphocytes and bind SRIF-14 with high affinity. Antigens from the schistosome eggs stimulate granuloma T lymphocytes to produce cytokines. Interferon-gamma (IFN-gamma) is one such cytokine made by CD4+ T lymphocytes. SRIF-14 suppresses antigen-induced IFN-gamma production from granuloma cells, and this effect is blocked by anti-sst2 antibody. SRIF was shown to inhibit IFN-gamma-induced immunoglobulin G2a (lgG2a) synthesis in murine schistosomiasis. SRIF also blocks substance P (SP)-stimulated IFN-gamma and lgG2a secretion. Schistosome-infected animals treated with the SRIF analog octreotide form smaller granulomas that secrete substantially less IFN-gamma and lgG2a. Unpublished observations suggest that SRIF does not modulate schistosome egg antigen- or concanavalin A-stimulated granuloma lymphocyte proliferation in murine schistosomiasis. In conclusion, SRIF may be an important factor in the control of the granulomatous inflammatory response in murine schistosomiasis.
在小鼠中探究了生长抑素（SRIF）在控制对曼氏血吸虫感染的肉芽肿性炎症反应中的作用。鼠类肉芽肿含有SRIF - 14。免疫反应性SRIF和前体SRIF定位于肉芽肿内巨噬细胞的细胞质颗粒中。肉芽肿含有前体SRIF的mRNA且无神经支配。炎症细胞产生SRIF的过程似乎是可诱导的。肉芽肿含有SRIF受体sst2A和sst2B的mRNA，它们主要在CD4⁺ T淋巴细胞上表达，并与SRIF - 14高亲和力结合。血吸虫卵抗原刺激肉芽肿T淋巴细胞产生细胞因子。干扰素 - γ（IFN - γ）是CD4⁺ T淋巴细胞产生的一种此类细胞因子。SRIF - 14抑制抗原诱导的肉芽肿细胞产生IFN - γ，且这种作用被抗sst2抗体阻断。已证明SRIF在小鼠血吸虫病中抑制IFN - γ诱导的免疫球蛋白G2a（IgG2a）合成。SRIF还阻断P物质（SP）刺激的IFN - γ和IgG2a分泌。用SRIF类似物奥曲肽治疗的血吸虫感染动物形成较小的肉芽肿，分泌的IFN - γ和IgG2a显著减少。未发表的观察结果表明，在小鼠血吸虫病中，SRIF不调节血吸虫卵抗原或伴刀豆球蛋白A刺激的肉芽肿淋巴细胞增殖。总之，SRIF可能是控制小鼠血吸虫病肉芽肿性炎症反应的一个重要因素。
