Immunodominance of LipL32 peptides revealed by leptospirosis sera and therapeutic monoclonal antibodies.

BACKGROUND/PURPOSE: Leptospirosis is a neglected zoonosis, imposing significant human and veterinary public health burdens. In this study, recombinant LipL32 and LipL32 middle domain of LipL32, and LipL32, and LipL32 of c-terminal LipL32 truncations were defined for immunodominance of the molecule during Leptospira infections revealed by leptospirosis sera.

RESULTS

IgM-dominant was directed to highly surface accessible LipL32 and Lipl32. IgG dominance of LipL32 revealed by rabbit anti-Leptospira sera and convalescent leptospirosis paired sera were mapped to highly accessible surface of middle LipL32 truncation whereas two LipL32 and LipL32 truncations were IgG-dominant when revealed by single leptospirosis sera. The IgM-dominant of LipL32 and IgG-dominant LipL32 peptides have highly conserved amino acids of 70% identity among pathogenic and intermediate Leptospira species and were mapped to the highly surface accessible area of LipL32 molecule that mediated interaction of host components. IgG dominance of two therapeutic epitopes located at LipL32 and LipL32 of mAbLPF1 and mAbLPF2, respectively has been shown less IgG-dominant (<30%), located outside IgG-dominant regions characterized by leptospirosis paired sera.

CONCLUSION

The IgM- and IgG-dominant LipL32 could be further perspectives for immunodominant LipL32-based serodiagnosis and LipL32 epitope-based vaccine.