Immunology Department, Pasteur Institute of Iran, No 69 Pasteur Ave, Tehran 13164, Iran.
Exp Parasitol. 2011 Feb;127(2):448-53. doi: 10.1016/j.exppara.2010.10.008. Epub 2010 Oct 28.
Leishmania (L.) tropica is a causative agent of human cutaneous and viscerotropic leishmaniasis. Immune response to L. tropica in humans and experimental animals are not well understood. We previously established that L. tropica infection induces partial protective immunity against subsequent challenge infection with Leishmania major in BALB/c mice. Aim of the present study was to study immunologic mechanisms of protective immunity induced by L. tropica infection, as a live parasite vaccine, in BALB/c mouse model. Mice were infected by L. tropica, and after establishment of the infection, they were challenged by L. major. Our findings shows that L. tropica infection resulted in protection against L. major challenge in BALB/c mice and this protective immunity is associated with: (1) a DTH response, (2) higher IFN-γ and lower IL-10 response at one week post-challenge, (3) lower percentage of CD4(+) lymphocyte at one month post-challenge, and (4) the source of IFN-γ and IL-10 were mainly CD4(-) lymphocyte up to one month post-challenge suggesting that CD4(-) lymphocytes may be responsible for protection induced by L. tropica infection in the studied intervals.
热带利什曼原虫（L. tropica）是人类皮肤和内脏利什曼病的病原体。人体和实验动物对 L. tropica 的免疫反应尚未得到很好的理解。我们之前已经证实，L. tropica 感染可诱导 BALB/c 小鼠对随后的大疱性利什曼原虫（Leishmania major）挑战感染产生部分保护免疫力。本研究旨在研究 L. tropica 感染（作为活寄生虫疫苗）在 BALB/c 小鼠模型中诱导保护性免疫的免疫学机制。用 L. tropica 感染小鼠，在感染建立后，用 L. major 对其进行攻击。我们的研究结果表明，L. tropica 感染可预防 BALB/c 小鼠感染大疱性利什曼原虫，这种保护性免疫与：（1）迟发型超敏反应（DTH）反应，（2）在攻击后一周产生更高的 IFN-γ 和更低的 IL-10 反应，（3）在攻击后一个月产生更低比例的 CD4(+)淋巴细胞，以及（4）IFN-γ 和 IL-10 的来源主要是 CD4(-)淋巴细胞，直至攻击后一个月，表明 CD4(-)淋巴细胞可能在研究期间对 L. tropica 感染诱导的保护作用负责。
