Mahmoudzadeh-Niknam Hamid, Kiaei Simin Sadat, Iravani Davood
Immunology Department, Pasteur Institute of Iran, No. 69 Pasteur Ave, Tehran 13164, Iran.
Korean J Parasitol. 2007 Jun;45(2):103-9. doi: 10.3347/kjp.2007.45.2.103.
Leishmania tropica and L. major are etiologic agents of human cutaneous leishmaniasis. Delayed type hypersensitivity (DTH) is an immunologic response that has been frequently used as a correlate for protection against or sensitization to leishmania antigen. In BALB/c mice, L. tropica infection results in non-ulcerating disease, whereas L. major infection results in destructive lesions. In order to clarify the immunologic mechanisms of these 2 different outcomes, we compared the ability of these 2 leishmania species in induction of DTH response in this murine model. BALB/c mice were infected with L. major or L. tropica, and disease evolution and DTH responses were determined. The results show that the primary L. major infection can exacerbate the secondary L. major infection and is associated with DTH response. Higher doses of the primary L. major infection result in more disease exacerbation of the secondary L. major infection as well as higher DTH response. L. tropica infection induces lower DTH responses than L. major. We have previously reported that the primary L. tropica infection induces partial protection against the secondary L. major infection in BALB/c mice. Induction of lower DTH response by L. tropica suggests that the protection induced against L. major by prior L. tropica infection may be due to suppression of DTH response.
热带利什曼原虫和硕大利什曼原虫是人类皮肤利什曼病的病原体。迟发型超敏反应（DTH）是一种免疫反应，常被用作针对利什曼原虫抗原的保护性或致敏性的相关指标。在BALB/c小鼠中，热带利什曼原虫感染导致非溃疡性疾病，而硕大利什曼原虫感染导致破坏性病变。为了阐明这两种不同结果的免疫机制，我们在这个小鼠模型中比较了这两种利什曼原虫诱导DTH反应的能力。用硕大利什曼原虫或热带利什曼原虫感染BALB/c小鼠，并确定疾病进展和DTH反应。结果表明，初次感染硕大利什曼原虫可加重再次感染硕大利什曼原虫的病情，并与DTH反应相关。更高剂量的初次感染硕大利什曼原虫会导致再次感染硕大利什曼原虫的病情加重更明显，同时DTH反应也更高。热带利什曼原虫感染诱导的DTH反应低于硕大利什曼原虫。我们之前报道过，初次感染热带利什曼原虫可诱导BALB/c小鼠对再次感染硕大利什曼原虫产生部分保护作用。热带利什曼原虫诱导较低的DTH反应表明，先前感染热带利什曼原虫诱导的针对硕大利什曼原虫的保护作用可能是由于DTH反应受到抑制。
