A Multiepitope Protein Based on Selected Synthetic Peptides Enables Effective Serological Screening of Exposure to Mycobacterium leprae.

Early and accurate identification of individuals exposed to leprosy is essential for controlling the transmission. Our study assessed the potential of a novel recombinant multiepitope protein, designed using five synthetic Mycobacterium leprae-specific peptides that were selected based on their prior performance in ELISA assays. The protein was expressed in a bacterial system and further evaluated in ELISA assays for IgG and IgM. The reactivity was assessed in 357 serum samples from leprosy patients, 234 household contacts (HHC), 26 tuberculosis patients, and 61 healthy controls from different regions of Brazil. The multiepitope protein showed strong IgG and IgM responses in HHC, with AUC values above 0.80. No significant differences in antibody responses were observed between HHC of paucibacillary and multibacillary patients, for either the peptides or the novel protein. Among leprosy patients, peptides and protein responses ranged from moderate to good (AUC 0.67-0.81). These findings highlight the utility of these novel markers as promising tools for serological screening of exposure to M. leprae.