Ali N, Afrin F
Leishmania Group, Indian Institute of Chemical Biology, Calcutta, India.
J Parasitol. 1997 Feb;83(1):70-5.
Leishmanial antigens (LAg) were used as a vaccine against Leishmania donovani, the causative agent of visceral leishmaniasis. BALB/c mice, immunized intraperitoneally with 20 micrograms of the antigen in phosphate-buffered saline (PBS) or entrapped in liposomes, were infected intravenously with 2 x 10(7) L. donovani promastigotes. Mice immunized with PBS and empty liposomes showed similar levels of parasite burdens in the liver and spleen. Injection of the antigen alone or entrapped in liposomes, followed with infection, induced significant levels of protection against the disease. After 2 and 4 mo of infection, mice immunized with free antigen induced 7.4% and 50.7% reduction in the liver parasite burden, respectively, compared to control (PBS) mice. With antigen encapsulated in liposome, the liver parasite burden was further reduced by 30.4% and 73% at 2 and 4 mo by infection, respectively. Splenic parasite burden was very low at 2 mo of infection. At 4 mo, the parasite level was reduced by 54.2% with free antigen and 69.3% with antigen entrapped in liposomes. Whereas the protection induced by the free antigen is mainly cell mediated, stimulation of an antibody response together with a strong delayed-type hypersensitivity may be responsible for the better protection with liposomal antigen.
利什曼原虫抗原（LAg）被用作抗杜氏利什曼原虫的疫苗，杜氏利什曼原虫是内脏利什曼病的病原体。将20微克抗原溶于磷酸盐缓冲盐水（PBS）中或包裹于脂质体中，经腹腔免疫BALB/c小鼠，然后静脉注射2×10⁷个杜氏利什曼原虫前鞭毛体。用PBS和空脂质体免疫的小鼠在肝脏和脾脏中的寄生虫负荷水平相似。单独注射抗原或包裹于脂质体中的抗原，随后进行感染，均可诱导出显著的疾病保护水平。感染2个月和4个月后，与对照（PBS）小鼠相比，用游离抗原免疫的小鼠肝脏寄生虫负荷分别降低了7.4%和50.7%。对于包裹于脂质体中的抗原，感染2个月和4个月时，肝脏寄生虫负荷分别进一步降低了30.4%和73%。感染2个月时脾脏寄生虫负荷非常低。在4个月时，游离抗原使寄生虫水平降低了54.2%，脂质体包裹的抗原使寄生虫水平降低了69.3%。游离抗原诱导的保护主要是细胞介导的，而脂质体抗原诱导的更好保护可能是由于刺激了抗体反应以及强烈的迟发型超敏反应。
