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Updated: Jun 5, 2026
Immuno-fluorescence Assay of Leptospiral Surface-exposed Proteins
Published on: July 1, 2011
Cross-protective immunity against leptospirosis elicited by a live, attenuated lipopolysaccharide mutant
Amporn Srikram1, Kunkun Zhang, Thanatchaporn Bartpho
1Faculty of Medicine, Melioidosis Research Center, Khon Kaen University, Khon Kaen, Thailand.
Background:
Leptospira species cause leptospirosis, a zoonotic disease found worldwide. Current vaccines against leptospirosis provide protection only against closely related serovars.
Methods:
We evaluated an attenuated transposon mutant of Leptospira interrogans serovar Manilae (M1352, defective in lipopolysaccharide biosynthesis) as a live vaccine against leptospirosis. Hamsters received a single dose of vaccine and were challenged with the homologous serovar (Manilae) and a serologically unrelated heterologous serovar (Pomona). Comparisons were made with killed vaccines. Potential cross-protective antigens against leptospirosis were investigated.
Results:
Live M1352 vaccine induced superior protection in hamsters against homologous challenge. The live vaccine also stimulated cross-protection against heterologous challenge, with 100% survival (live M1352) versus 40% survival (killed vaccine). Hamsters receiving either vaccine responded to the dominant membrane proteins LipL32 and LipL41. Hamsters receiving the live vaccine additionally recognized LA3961/OmpL36 (unknown function), Loa22 (OmpA family protein, recognized virulence factor), LA2372 (general secretory protein G), and LA1939 (hypothetical protein). Manilae LigA was recognized by M1352 vaccinates, whereas LipL36 was detected in Pomona.
Conclusion:
This study demonstrated that a live, attenuated vaccine can stimulate cross-protective immunity to L. interrogans and has identified antigens that potentially confer cross-protection against leptospirosis.
Insights
A novel live attenuated vaccine against leptospirosis demonstrated superior protection and cross-protection in hamsters. This live vaccine identified key antigens for broader immunity against Leptospira interrogans.
Area of Science:
- Microbiology
- Immunology
- Vaccinology
Background:
- Leptospirosis is a global zoonotic disease caused by Leptospira species.
- Existing vaccines offer limited protection, primarily against homologous serovars.
Purpose of the Study:
- To evaluate an attenuated Leptospira interrogans serovar Manilae mutant (M1352) as a live vaccine.
- To assess its efficacy against homologous and heterologous serovar challenge.
- To identify potential cross-protective antigens.
Main Methods:
- An attenuated transposon mutant (M1352) of L. interrogans serovar Manilae was used as a live vaccine in hamsters.
- Vaccinated hamsters were challenged with homologous (Manilae) and heterologous (Pomona) serovars.
- Immune responses to specific antigens were analyzed and compared with killed vaccines.
Main Results:
- The live M1352 vaccine provided superior protection against homologous challenge.
- Significant cross-protection was observed against heterologous challenge (100% survival with live vaccine vs. 40% with killed vaccine).
- The live vaccine elicited responses to multiple antigens, including LipL32, LipL41, LA3961/OmpL36, Loa22, LA2372, and LA1939.
Conclusions:
- A live, attenuated L. interrogans vaccine can induce cross-protective immunity.
- Specific antigens recognized by the live vaccine may confer broad protection against leptospirosis.
