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Cell surface display system for Lactococcus lactis: a novel development for oral vaccine
A R Raha1, N R S Varma, K Yusoff
1Department of Bioprocess Technology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang, 43400, Selangor, Malaysia. raha@fsb.upm.edu.my
Applied Microbiology and Biotechnology
|January 7, 2005
Summary
Researchers developed a novel system to display proteins on the surface of food-grade Lactococcus lactis bacteria. This advance enables live bacterial vehicles for delivering vaccines and pharmaceuticals, showing stable protein anchoring for at least five days.
Area of Science:
- Microbiology and Biotechnology
- Molecular Biology and Genetic Engineering
- Vaccine Development and Pharmaceutical Delivery
Background:
- Food-grade Lactococcus lactis is a promising candidate for live bacterial vectors.
- Efficient display of heterologous proteins on bacterial surfaces is crucial for applications like vaccines.
- Existing methods for protein display on L. lactis require optimization for stability and broad applicability.
Purpose of the Study:
- To engineer a novel cell surface display system for recombinant proteins on Lactococcus lactis.
- To validate the anchoring efficiency and stability of a cell wall-binding fragment (AcmA') on L. lactis.
- To demonstrate the display of Enterovirus 71 (EV71) VP1 protein epitopes using this system.
Main Methods:
- Construction of a plasmid vector (pSVac) containing the AcmA' cell wall-binding domain.
- Expression and purification of the AcmA' fragment in Escherichia coli.
- Confirmation of surface anchoring on L. lactis using ELISA and immunofluorescence assays.
- Stability assays for fusion proteins (AcmA/A1, AcmA/A3) on the bacterial surface.
- Cloning and expression of EV71 VP1 protein fragments (A1, A3) fused to AcmA' for surface display.
Main Results:
- The AcmA' fragment was successfully expressed, purified, and anchored to the outer surface of L. lactis MG1363.
- The AcmA' fragment demonstrated strong binding to various lactococcal and Lactobacillus strains, and weaker binding to Bacillus sphericus.
- Fusion proteins (AcmA/A1, AcmA/A3) remained stably docked on the L. lactis surface for at least 5 days.
- EV71 VP1 protein epitopes (A1, A3) were successfully displayed on the L. lactis surface, confirmed by whole-cell ELISA.
Conclusions:
- A robust cell surface display system for L. lactis has been successfully developed using the AcmA' cell wall-binding domain.
- This system enables stable display of heterologous proteins and epitopes, with potential applications in vaccine and pharmaceutical delivery.
- The technology shows promise for displaying peptides and proteins on the surface of L. lactis and other Gram-positive bacteria.