Increased immunogenicity to LipL32 of Leptospira interrogans when expressed as a fusion protein with the cholera toxin B subunit

ALEJANDRA MARIEL HABARTA; PATRICIA ABREU; NOELIA OLIVERA; PRISCILA HAUK; MAIA CEDOLA; MARÍA FLORENCIA FERRER; PAULO LEE HO; RICARDO MARTÍN GÓMEZ

CURRENT MICROBIOLOGY

SPRINGER

Año: 2011 vol. 62 p. 526 - 531

0343-8651

Leptospirosis is one of the most widespread zoonosis in the world. The developmentof a recombinant leptospira vaccine remains a challenge. In the present study, wecloned the Leptospira interrogans open reading frame (ORF) coding the externalmembrane protein LipL32, an immunodominant antigen found in all pathogenicleptospira, downstream of the highly immunogenic cholera toxin B subunit (CTB)ORF. Expression and assembly of the CTB-LipL32 fusion protein into oligomericstructures of pentameric size were observed in soluble fractions by Western blotanalysis. The CTB-LipL32 protein demonstrated strong affinity formonosialotetrahexosylgaglioside (GM1-ganglioside) in an enzyme-linkedimmunosorbent assay (ELISA), suggesting that the antigenic sites for binding andproper folding of the pentameric CTB structure were conserved. Furthermore, antiseraagainst LipL32 also recognized the CTB-LipL32 fusion protein, suggesting thatLipL32 also conserved its antigenic sites, a fact confirmed by an ELISA assayshowing soluble CTB-LipL32 recognition by sera from convalescent patients. Inaddition, soluble CTB-LipL32 generated higher specific titers in mice immunizedwithout external adjuvant than co-administration of CTB with LipL32. The datapresented here provide support for CTB-LipL32 as a promising antigen for use in thecontrol and study of leptospirosis.