Importance of L. Infantum H2B Recombinant Antigen for Serodiagnosis of Visceral Leishmaniasis

Visceral leishmaniasis (VL) can lead to death in more than 95% of cases if left untreated. Accurate and early diagnosis has an important role in reducing mortality rate of this disease.

To express recombinant H2B antigen from an Iranian isolate of Leishmania Infantum and evaluate its efficacy in the diagnosis of VL.

The recombinant H2B antigen was produced in a prokaryotic system, and its efficacy for VL diagnosis was evaluated by ELISA. The serum samples from 80 VL patients, 100 individuals from endemic and non-endemic regions of VL, and 58 non-VL patients were collected. VL cases were confirmed based on the clinical sign, positive IFAT (>64), real time PCR, and response to treatment.

The H2B gene sequence of the Iranian L. infantum isolate had about 4% diversity in comparison with the H2B gene of the L. infantum counterpart. ELISA, using the produced H2B recombinant antigen, showed sensitivity of 71.25% (95% CI: 60.05%-80.82%) and specificity of 69.62% (95% CI: 61.81%-76.68%) regarding VL diagnosis.

Recombinant H2B antigen expressed in the prokaryotic system had suboptimal performance for the serological diagnosis of VL. It seems that the production and expression of recombinant H2B antigen in a eukaryotic system may enhance the performance of this antigen in the diagnosis of VL in Iran.