Production and characterization of monoclonal antibodies recognizing a common 57-kDa antigen of Leishmania species.

BACKGROUND The therapy of leishmania infection is difficult and each year 1.5 million new cases of cutaneous leishmaniasis and 500,000 new cases of visceral leishmaniasis are estimated, therefore, there is a need for an effective vaccine. Monoclonal antibody (mAb) is one of the suitable methods for isolation and purification of leishmania antigens. In this report, we produced several mAb against leishmania infantum antigens for antigen purification to be used as candidate vaccine. METHODS BALB/c mice were injected with freeze-thawed promastigote twice together with Freund adjuvant. Three days before fusion, antigen in saline was injected into the tail vain and then mice were killed and the spleen lymphocytes were fused with myeloma SP2/0. RESULTS Five mAb against promastigote form of Leishmania infantum parasite were obtained. Western-blot analysis showed that these mAb recognize a band of 57- kDa protein either in parasite lysate or on whole L. infantum, L. tropica, L. major and L. donovani. It seems that the 57 kDa-protein is the major surface leishmania antigen (gp63) that is neither stage-specific nor differentially regulated. These mAb do not recognize the recombinant gp63 antigen and seems recognizing only the native form of a gp63 isoform. The IgG1 mAb was purified by affinity column and was used to purify 57 kDa antigens from Leishmania lysate. CONCLUSION Since these antibodies recognizing one specific protein band in 4 different strains of leishmania, they could be used for leishmania diagnostic kits and also for purification of antigen to be tested for its protective effect against leishmania infection.