In Vitro Infectivity of Leishmania major Isolated from Patients with Different Clinical Forms of Cutaneous Leishmaniasis and Its Association with Parasite Zymodems

Background: The aim of this study was to characterize the Leishmania parasites isolated from cutaneous leishmaniasis (CL) patients in Fars Province in Iran and to compare the potential infectivity of the isolates in macrophage cell line. Moreover, attempt was made to find out the association between parasite infectivity and their zymodems. Methods: Twenty samples were taken from the skin lesion of CL patients. The samples were cultured in biphasic media followed by mass cultivation in RPMI medium. Each isolate was tested for the activity of the 5 enzymes including glucose phosphate isomerase (GPI), malate dehydrogenase (MDH), nucleoside hydrolase 1&2 (NH1 & NH2), and phosphoglucomutase (PGM). The enzymatic profiles of the isolates were compared with WHO reference strains. Specific PCR (primers: LIN17 & LIN R4) and RAPD-PCR were used as complementary methods for characterization of the isolates. Results: Isoenzyme electrophoresis showed that all of the isolates were L. major. PCR with LIN17 and LIN R4 and RAPD-PCR with AB-07 primers further determined the isolates as L. major. Results of macrophage infectivity experiment, using 1774 cell line, showed that the most virulent isolates were related to Z1 with 63% macrophage infectivity rate. A well correlation was found between the infectivity rate of the isolates and type of ulcer. Those isolates with high infectivity rate were involved in more severe, ulcerative or erythmatose lesions in CL patients. Conclusion: The most invasive isolates might be a good candidate for immunological studies and for vaccine development.