Rachamim N, Jaffe C L
Biophysics-MacArthur Center for Molecular Biology of Tropical Diseases, Weizmann Institute of Science, Rehovot, Israel.
J Immunol. 1993 Mar 15;150(6):2322-31.
A protein purified from Leishmania donovani promastigotes, dp72, was shown to partially protect BALB/c mice against a challenge by this parasite. Immunized mice infected i.v. with 10(7) L. donovani promastigotes showed a 0, 60, and 78% reduction in liver parasite burden compared with the control mice at each time point examined after challenge, 1, 20, and 108 days, respectively. Western blotting demonstrated that the sera from the immune mice, which reacted specifically with dp72 in lysates of L. donovani, cross-reacted with one major band in total homogenates of Leishmania major and Leptomonas collosoma. Lymphocyte proliferation to crude and pure parasite Ag was also examined in mice immunized with dp72. Strong proliferation was found at low concentrations of crude L. donovani Ag (0.5 micrograms/ml) and with pure dp72. Proliferation at higher concentrations to crude L. major and L. collosoma Ag was observed. Little or no reaction (stimulation index < 1.0) was seen with other pure leishmanial Ag, including gp70-2, the promastigote surface protease, and lipophosphoglycan. Depletion in vitro of the CD4+ T cell subset from immune spleen cells abolished proliferation to dp72, whereas depletion of CD8+ T cells enhanced proliferation to the pure Ag. Experiments in vivo showed that immunized mice treated with antibodies to either CD4+, CD8+, both T cell subsets, or to IFN-gamma had larger LPB (178, 173, 176, and 130%, respectively) after challenge with L. donovani than nonimmunized controls. Mice immunized with dp72 but treated with either PBS or mouse Ig showed reduced LPB, 81 and 61%, respectively, compared with the nonimmunized animals. BALB/c mice immunized with dp72 were also protected against L. major which causes cutaneous leishmaniasis. Immunized mice infected with either 10(4) or 10(6) promastigotes did not develop lesions. Limiting dilution assays confirmed the protection.
从杜氏利什曼原虫前鞭毛体中纯化出的一种蛋白质dp72，已被证明能部分保护BALB/c小鼠免受该寄生虫的攻击。静脉注射10⁷个杜氏利什曼原虫前鞭毛体的免疫小鼠，在攻击后1天、20天和108天的每个检测时间点，其肝脏寄生虫负荷与对照小鼠相比分别降低了0%、60%和78%。蛋白质印迹法表明，免疫小鼠的血清与杜氏利什曼原虫裂解物中的dp72发生特异性反应，与硕大利什曼原虫和科氏细滴虫的总匀浆中的一条主要条带发生交叉反应。在用dp72免疫的小鼠中也检测了淋巴细胞对粗制和纯寄生虫抗原的增殖情况。在低浓度的粗制杜氏利什曼原虫抗原（0.5微克/毫升）和纯dp72存在时发现有强烈的增殖。在较高浓度下观察到对粗制硕大利什曼原虫和科氏细滴虫抗原的增殖。对其他纯利什曼原虫抗原，包括gp70-2、前鞭毛体表面蛋白酶和脂磷壁酸聚糖，几乎没有反应（刺激指数<1.0）。从免疫脾细胞中体外去除CD4⁺T细胞亚群可消除对dp72的增殖反应，而去除CD8⁺T细胞则增强对纯抗原的增殖反应。体内实验表明，用针对CD4⁺、CD8⁺、两个T细胞亚群或IFN-γ的抗体处理的免疫小鼠，在受到杜氏利什曼原虫攻击后的肝脏寄生虫负荷比未免疫的对照小鼠更大（分别为178%、173%、176%和130%）。用dp72免疫但用PBS或小鼠Ig处理的小鼠，其肝脏寄生虫负荷与未免疫动物相比分别降低了81%和61%。用dp72免疫的BALB/c小鼠也受到了针对引起皮肤利什曼病的硕大利什曼原虫的保护。感染10⁴或10⁶个前鞭毛体的免疫小鼠未出现病变。有限稀释分析证实了这种保护作用。
