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Updated: Jun 20, 2026
Enriching Subcellular Proteins in Leptospira Using a Triton X-114-Based Fractionation Approach
Published on: August 8, 2025
Molecular characterization of the pL40 protein in Leptospira interrogans
Wei Zhao1, Chun-Yan Chen, Xiang-Yan Zhang
1Department of Medical Microbiology and Parasitology, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China.
Abstract:
Leptospirosis is a widespread zoonotic disease caused by pathogenic leptospires. The identification of outer membrane proteins (OMPs) conserved among pathogenic leptospires, which are exposed on the leptospiral surface and expressed during mammalian infection, has become a major focus of leptospirosis research. pL40, a 40 kDa protein coded by the LA3744 gene in Leptospira interrogans, was found to be unique to Leptospira. Triton X-114 fractionation and flow cytometry analyses indicate that pL40 is a component of the leptospiral outer membrane. The conservation of pL40 among Leptospira strains prevalent in China was confirmed by both Western blotting and PCR screening. Furthermore, the pL40 antigen could be recognized by sera from guinea pigs and mice infected with low-passage L. interrogans. These findings indicate that pL40 may serve as a useful serodiagnostic antigen and vaccine candidate for L. interrogans.
Insights
Researchers identified a novel outer membrane protein, pL40, in Leptospira interrogans. This protein is conserved in prevalent strains and shows potential as a diagnostic tool and vaccine candidate for leptospirosis.
Area of Science:
- Microbiology
- Immunology
- Infectious Diseases
Background:
- Leptospirosis is a significant zoonotic disease caused by pathogenic Leptospira species.
- Identifying conserved outer membrane proteins (OMPs) on Leptospira is crucial for diagnostics and vaccines.
- The pL40 protein, encoded by LA3744 in Leptospira interrogans, is a potential candidate.
Purpose of the Study:
- To characterize the pL40 protein of Leptospira interrogans.
- To determine its localization within the bacterium.
- To assess its conservation and immunogenicity for diagnostic and vaccine potential.
Main Methods:
- Triton X-114 fractionation to isolate outer membrane proteins.
- Flow cytometry to confirm surface exposure.
- Western blotting and PCR screening for conservation analysis.
- Serological testing with infected animal sera.
Main Results:
- pL40 is a 40 kDa protein localized to the outer membrane of Leptospira.
- The protein is conserved among prevalent Leptospira strains in China.
- pL40 is recognized by antibodies from infected rodents, indicating immunogenicity.
Conclusions:
- pL40 is a conserved Leptospira outer membrane protein.
- It demonstrates potential as a serodiagnostic antigen for leptospirosis.
- pL40 is a promising candidate for developing a vaccine against Leptospira interrogans infection.
