Effect of Leishmania gerbilli injection on mice immunization against cutaneous leishmaniasis (CL) caused by Leishmania major

In the present study Leishmania gerbilli were used to immunize BALB/c mice against pathogenic strains of leishmania to determine whether injection of L. gerbilli in mice could protect them against later L. major inoculation. Eighty female BALB/c mice were divided by random in eight groups. Promastigotes of L. major and L. gerbilli were used. Mice were inoculated with three different doses of L. gerbilli (3 x 10(6), 2 x 10(7) and 5 x 10(7)) via subcutaneous (SC) in the base of their tails or interpretoen (IP). Forty days after the first injection, all mice received the same doses as a booster. Two control groups received PBS (SC or IP) only. All BALB/c mice were inoculated subcutaneously with 2 x 10(6). Promastigotes of L. major in the base of their tails after 75 days of the first injection of L. gerbilli. When leishmania lesion developed (35 days after challenge), the size was measured and continued once a week for 12 weeks. Meanwhile, the liver and spleen samples of dead mice moved to culture media and examined for the parasite. Delayed Type Hypersensitivity (DTH) and immunoflurecent tests were used to determine results of immunization. Compared with the control group and the other groups that received different doses of L. gerbilli via IP, an evident decrease in lesion size was observed in group that received 2 x 10(7) promastigotes (p < 0.05). By contrast, in those groups received L. gerbilli subcutaneously, no difference was observed through the different doses of inoculated parasite. Comparison of the inoculation styles showed that IP method caused smaller lesions than SC (p < 0.05).