Comparative screening of recombinant antigen thermostability for improved leptospirosis vaccine design |
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Authors: | Christopher P Ptak Mohd Akif Ching-Lin Hsieh Alex Devarajan Ping He Yinghua Xu Robert E Oswald Yung-Fu Chang |
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Institution: | 1. Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York;2. Department of Molecular Medicine, College of Veterinary Medicine, Cornell University, Ithaca, New York;3. Department of Microbiology and Immunology, Institutes of Medical Science, Shanghai Jiao Tong University School of Medicine, Shanghai, China;4. Key Laboratory of the Ministry of Health for Research on Quality and Standardization of Biotech Products, National Institutes for Food and Drug Control, Beijing, China |
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Abstract: | Recombinant antigens exhibit targeted protectiveproperties and offer important opportunities in the development of therapeutic technologies. Biophysical and structural methods have become important tools for the rational design and engineering of improved antigen-based vaccines. Vaccines containing Leptospira immunoglobulin-like (Lig) protein-derived antigens are currently the most promising candidates for protective immunity against the globally prevalent bacterial pathogen, Leptospira interrogans; however, vaccine trials using these domains have produced inconsistent results. Here, we compare the thermostability of domains from the main immunogenic regions from major leptospiral antigens, LigA and LigB. By measuring temperature-dependent fluorescence decay of the hydrophobic core tryptophan, 17 individual Lig protein immunoglobulin-like (Ig-like) domains were shown to display a broad range of unfolding temperatures. For a majority of the domains, stability issues begin to occur at physiologically relevant temperatures. A set of chimeric Ig-like domains was used to establish the ability of transplanted domain regions to enhance thermostability. Further insights into the determinants for domain stabilization were explored with nuclear magnetic resonance dynamics and mutational analysis. The current study has yielded a set of thermostable Ig-like domain scaffolds for use in engineering antigen-based vaccines and demonstrates the importance of incorporating thermostability screening as a design parameter. |
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Keywords: | immunoglobulin-like domain Leptospira recombinant antigen thermostability vaccine |
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