do Valle T Zaverucha, Gaspar E B, Souza-Lemos C, Souza C S F, Márquez F B Zamora, Baetas-da-Cruz W, d'Escofier L N, Côrte-Real S, Calabrese K S, da Costa S C Gonçalves
Laboratório de Imunomodulação, Departamento de Protozoologia, Instituto Oswaldo Cruz, Fiocruz, RJ.
Immunol Invest. 2007;36(4):473-92. doi: 10.1080/08820130701360972.
A technique developed in Trypanosoma cruzi biochemical studies was successfully used to fractionate Leishmania (Leishmania) amazonensis promastigotes. Ultrastructural analyses revealed a membrane fraction (MF) associated to subpellicular microtubules, a ribosomal-rich microsomal fraction (MicF), and a flagellar fraction (FF) free of associated membrane. All fractions proved to be immunogenic through delayed type hypersensitivity reaction assays. Therefore, a protocol was designed to test whether these fractions could elicit a protective response in mice infected by L. (L), amazonensis. The protocol consisted of a BCG injection (as cellular immunity inducer), followed by cyclophosphamide (once its cytotoxic effect is over, this immunosuppressor can increase the number of circulating leukocytes), then an injection with one of the fractions followed by a challenge. When compared to infected control animals, mice injected with any of the fractions presented a smaller footpad swelling, especially those injected with MicF or FF. Macroscopically, immunized mice under modulation by BCG presented no swelling. Histopathological studies performed on day 120 revealed fewer amastigotes and more intense inflammation in lesions of MicF and FF injected mice. Animals injected with MF presented an intermediate pattern. Parasite quantification corroborated these results. The results show that all fractions are potent immunostimulators, but MicF and FF have the strongest protective ability.
一种在克氏锥虫生化研究中开发的技术成功用于分离亚马逊利什曼原虫前鞭毛体。超微结构分析揭示了一个与表膜下微管相关的膜部分（MF）、一个富含核糖体的微粒体部分（MicF）和一个无相关膜的鞭毛部分（FF）。通过迟发型超敏反应试验证明所有部分都具有免疫原性。因此，设计了一个方案来测试这些部分是否能在感染亚马逊利什曼原虫的小鼠中引发保护性反应。该方案包括注射卡介苗（作为细胞免疫诱导剂），随后注射环磷酰胺（一旦其细胞毒性作用结束，这种免疫抑制剂可增加循环白细胞数量），然后注射其中一个部分，接着进行攻击。与感染的对照动物相比，注射任何一个部分的小鼠足垫肿胀较小，尤其是注射MicF或FF的小鼠。宏观上，在卡介苗调节下免疫的小鼠没有肿胀。在第120天进行的组织病理学研究显示，注射MicF和FF的小鼠病变中的无鞭毛体较少，炎症更强烈。注射MF的动物呈现中间模式。寄生虫定量证实了这些结果。结果表明，所有部分都是有效的免疫刺激剂，但MicF和FF具有最强的保护能力。
