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Updated: Jun 24, 2026
Polymerase Chain Reaction and Dot-Blot Hybridization for Leptospira Detection in Water Samples
Published on: June 14, 2024
Humanized-monoclonal antibody against heterologous Leptospira infection
Santi Maneewatch1, Yuwaporn Sakolvaree, Pramuan Tapchaisri
1Graduate Program, Faculty of Allied Health Sciences, Thammasat University, Rangsit Center, Pathum-thani 12120, Thailand.
Abstract:
Patients with leptospirosis are commonly treated with antibiotics. Jarisch-Herxheimer reaction caused by toxic bacterial substances massively released as a result of the antibiotic mediated-bacterial lysis occurs in some patients which may aggravate the existing severe clinical manifestations. In this study, a humanized-murine single-chain monoclonal antibody (HuScFv) was produced and tested as an alternative of antibiotics for treatment of leptospirosis. Complementary DNA was prepared from total RNA of a murine hybridoma clone secreting monoclonal antibody (MAb) specific to LipL32 of pathogenic Leptospira spp. The MAb had therapeutic efficacy in Leptospira challenged hamsters. The VH and VL coding sequences were amplified using the cDNA as a template. The sequences were linked to form a single-chain variable murine DNA fragment (muscFv). CDR sequences of the muscFv were grafted onto the best matching human VH and VL immunoglobulin frameworks. After cloning of the humanized murine DNA sequences (huscFv) into a phagemid vector and the vector was introduced into competent Escherichia coli, the HuScFv was produced. On the same weight basis, the HuScFv possessed equal neutralizing activities to the murine ScFv counterpart against heterologous Leptospira-mediated hemolysis in vitro and rescued hamsters from a heterologous Leptospira lethal challenge. The HuScFv antibody has high therapeutic potential as an alternative to antibiotics for human leptospirosis, especially for drug hypersensitive patients.
Insights
A novel humanized-murine single-chain variable fragment (HuScFv) antibody shows promise as an alternative to antibiotics for treating leptospirosis. This antibody effectively neutralizes Leptospira bacteria and protects hamsters, offering hope for drug-hypersensitive patients.
Area of Science:
- Immunology
- Infectious Diseases
- Biotechnology
Background:
- Leptospirosis treatment commonly involves antibiotics, which can trigger Jarisch-Herxheimer reactions due to bacterial lysis.
- These reactions can worsen severe clinical manifestations in leptospirosis patients.
- An alternative, safer treatment for leptospirosis is needed, particularly for those with drug hypersensitivity.
Purpose of the Study:
- To develop and evaluate a humanized-murine single-chain variable fragment (HuScFv) antibody as a potential alternative to antibiotics for leptospirosis treatment.
- To assess the therapeutic efficacy and neutralizing activity of the developed HuScFv against pathogenic Leptospira species.
Main Methods:
- Complementary DNA (cDNA) was prepared from a murine hybridoma clone secreting a monoclonal antibody (MAb) specific to LipL32 of pathogenic Leptospira.
- The variable heavy (VH) and variable light (VL) coding sequences were amplified and linked to form a murine single-chain variable fragment (muscFv).
- Complementarity-determining region (CDR) sequences of the muscFv were grafted onto human immunoglobulin frameworks to create the humanized scFv (huscFv), which was then produced in Escherichia coli.
Main Results:
- The produced HuScFv demonstrated equivalent neutralizing activity to its murine counterpart against Leptospira-mediated hemolysis in vitro.
- On a weight-for-weight basis, the HuScFv successfully rescued hamsters from a lethal challenge with pathogenic Leptospira.
- The HuScFv exhibited significant therapeutic efficacy in a hamster model of leptospirosis.
Conclusions:
- The humanized-murine single-chain variable fragment (HuScFv) antibody possesses high therapeutic potential as an alternative to conventional antibiotics for treating human leptospirosis.
- This HuScFv offers a promising option for patients with leptospirosis, especially those who are hypersensitive to antibiotics.
- Further development of this HuScFv could lead to a safer and more effective treatment strategy for leptospirosis.
