Cloning and expression of Leishmania major superoxide dismutase B1: A potential target antigen for serodiagnosis of Leishmaniasis.

Background: Leishmaniasis- a neglected public health problem- is a group of diseases affecting an estimated 12 million people worldwide.

Objective: In the present study, recombinant Leishmania major superoxide dismutase B1 (rLmSODB1) has been utilized as a potential antigen for the serodiagnosis of human cutaneous (CL) and visceral leishmaniasis (VL) in the endemic regions of southern part of Iran. Additionally, the sensitivity and specificity of ELISA-based serodiagnosis using rLmSODB1 and the soluble Leishmania antigen (SLA) were compared.

Methods: For the first time, rLmSODB1 has been cloned successfully and used for ELISA-based serodiagnosis. Sera from 30 CL and 24 VL cases were included in this study. Additional studies were also done for the evaluation of cross-reactivity using sera from 41 endemic controls including normal endemic donors (n=20), systemic lupus erythematosus patients (n=5), rheumatoid arthritis patients (n=5), and patients with tuberculosis (n=11).

Results: Analysis indicated that rLmSODB1 was recognized by 62.5% and 13.3% of sera from patients with VL and CL, showing a sensitivity of 72.7% and 53.6%, respectively. However 95.8% of VL and 30% of CL sera reacted with SLA, revealing sensitivities of 96% and 58.8%, respectively. Additionally, from 41 sera collected either from healthy subjects or patients affected with other diseases, 97.5% were negative with SLA or rLmSODB1 (specificity 97.6%).

Conclusion: These results show that rLmSODB1 almost does not react with sera from patients with tuberculosis and autoimmune diseases and may be considered as a candidate antigen for the specific immunodiagnosis of visceral leishmaniasis.