Immunotherapy Using Autoclaved L. major Antigens and M. vaccae with Meglumine Antimoniate, for the Treatment of Experimental Canine Visceral Leishmaniasis

BACKGROUND: To evaluate immunotherapy against canine visceral leishmaniasis, Leishmania major antigen and heat-killed Mycobacterium vaccae (SRL172) were used as stimulators of immune defense mechanisms and the results were compared with standard chemotherapy meglumine antimoniate. METHODS: Nineteen mongrel dogs aging 1-3 years old were used in this experiment. Infection was carried out in 15 out of 19 dogs using L. infantum, isolated from a naturally infected poly-symptomatic dog. RESULTS: All the cases showed positive serologic results by direct agglutination test during 30-60 days following inoculation. In the first group, which was under chemotherapy (Glucantime(R)), one of the members showed recurrence of the disease despite rapid effect of the therapeutic protocol. Immunotherapy using SRL172 caused complete cleaning of the parasite in group 2, but the speed was less than Glucantime. Immunotherapy using L. major antigen combined with M. vaccae in group 3 and combine administration of immunotherapy and chemotherapy in group 4 both were with relapsing of one case in each group. Group 5 and 6 were consisted of positive and negative control dogs, respectively. CONCLUSION: Immunotherapy seems to be an adjuvant in treatment of canine leishmaniasis but it needs more investigation for final confirmation.