Cardoso D F, Lopes-Ferreira M, Faquim-Mauro E L, Macedo M S, Farsky S H
Laboratory of Immunopathology, Institute Butantan, São Paulo, Brazil.
Mediators Inflamm. 2001 Jun;10(3):125-33. doi: 10.1080/09629350124986.
Crotoxin (CTX) is a potent neurotoxin from Crotalus durissus terrificus snake venom (CdtV) composed of two subunits: one without catalytic activity (crotapotin), and a basic phospolipase A2. Recent data have demonstrated that CdtV or CTX inhibit some immune and inflammatory reactions.
The aim of this paper was to investigate the mechanisms involved in these impaired responses.
Male Swiss mice were bled before and at different intervals of time after subcutaneous injection of CTX or bovine serum albumin (BSA) (control animals). The effect of treatments on circulating leukocyte mobilisation and on serum levels of interleukin (IL)-6, IL-10, interferon (IFN)-gamma and corticosterone were investigated. Spleen cells from treated animals were also stimulated in vitro with concanavalin A to evaluate the profile of IL-4, IL-6, IL-10 or IFN-gamma secretion. Cytokine levels were determined by immunoenzymatic assay and corticosterone levels by radioimmunoassay. To investigate the participation of endogenous corticosteroid on the effects evoked by CTX, animals were treated with metyrapone, an inhibitor of glucocorticoid synthesis, previous to CTX treatment.
Marked alterations on peripheral leukocyte distribution, characterised by a drop in the number of lymphocytes and monocytes and an increase in the number of neutrophils, were observed after CTX injection. No such alteration was observed in BSA-treated animals. Increased levels of IL-6, IL-10 and corticosterone were also detected in CTX-injected animals. IFN-gamma levels were not modified after treatments. In contrast, spleen cells obtained from CTX-treated animals and stimulated with concanavalin A secreted less IL-10 and IL-4 in comparison with cells obtained from control animals. Metyrapone pretreatment was effective only to reverse the neutrophilia observed after CTX administration.
Our results suggest that CTX may contribute to the deficient inflammatory and immune responses induced by crude CdtV. CTX induces endogenous mechanisms that are responsible, at least in part, for these impaired responses.
响尾蛇毒素（CTX）是一种来自剧毒矛头蝮蛇毒液（CdtV）的强效神经毒素，由两个亚基组成：一个无催化活性（巴曲酶）和一个碱性磷脂酶A2。最近的数据表明，CdtV或CTX可抑制一些免疫和炎症反应。
本文旨在研究这些反应受损所涉及的机制。
雄性瑞士小鼠在皮下注射CTX或牛血清白蛋白（BSA）（对照动物）之前及之后的不同时间间隔取血。研究了处理对循环白细胞动员以及白细胞介素（IL）-6、IL-10、干扰素（IFN）-γ和皮质酮血清水平的影响。还体外使用伴刀豆球蛋白A刺激处理动物的脾细胞，以评估IL-4、IL-6、IL-10或IFN-γ的分泌情况。通过免疫酶测定法测定细胞因子水平，通过放射免疫测定法测定皮质酮水平。为了研究内源性皮质类固醇对CTX诱发效应的参与情况，在CTX处理前用甲吡酮（一种糖皮质激素合成抑制剂）处理动物。
注射CTX后观察到外周白细胞分布有明显改变，其特征是淋巴细胞和单核细胞数量减少，中性粒细胞数量增加。在BSA处理的动物中未观察到这种改变。在注射CTX的动物中还检测到IL-6、IL-10和皮质酮水平升高。处理后IFN-γ水平未改变。相反，与从对照动物获得的细胞相比，从CTX处理的动物获得并经伴刀豆球蛋白A刺激的脾细胞分泌的IL-10和IL-4较少。甲吡酮预处理仅能有效逆转CTX给药后观察到的中性粒细胞增多。
我们的结果表明，CTX可能导致粗制CdtV诱导的炎症和免疫反应不足。CTX诱导的内源性机制至少部分地导致了这些受损反应。
