title: Xanthan gum as an adjuvant in a subunit vaccine preparation against leptospirosis.
abstract: Leptospiral immunoglobulin-like (Lig) proteins are of great interest due to their ability to act as mediators of pathogenesis, serodiagnostic antigens, and immunogens. Purified recombinant LigA protein is the most promising subunit vaccine candidate against leptospirosis reported to date, however, as purified proteins are weak immunogens the use of a potent adjuvant is essential for the success of LigA as a subunit vaccine. In the present study, we compared xanthan pv. pruni (strain 106), aluminium hydroxide (alhydrogel), and CpG ODN as adjuvants in a LigA subunit vaccine preparation. Xanthan gum is a high molecular weight extracellular polysaccharide produced by fermentation of Xanthomonas spp., a plant-pathogenic bacterium genus. Preparations containing xanthan induced a strong antibody response comparable to that observed when alhydrogel was used. Upon challenge with a virulent strain of L. interrogans serovar Copenhageni, significant protection (Fisher test, P < 0.05) was observed in 100%, 100%, and 67% of hamsters immunized with rLigANI-xanthan, LigA-CpG-xanthan, and rLigANI-alhydrogel, respectively. Furthermore, xanthan did not cause cytotoxicity in Chinese hamster ovary (CHO) cells in vitro. The use of xanthan as an adjuvant is a novel alternative for enhancing the immunogenicity of vaccines against leptospirosis and possibly against other pathogens.
authors.affiliation: Unidade de Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, 96010-900 Pelotas, RS, Brazil.
authors.forename: Katia L
authors.initials: KL
authors.lastname: Bacelo
authors.affiliation: Unidade de Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, 96010-900 Pelotas, RS, Brazil.
authors.forename: Daiane D
authors.initials: DD
authors.lastname: Hartwig
authors.affiliation: Unidade de Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, 96010-900 Pelotas, RS, Brazil.
authors.forename: Fabiana K
authors.initials: FK
authors.lastname: Seixas
authors.affiliation: Unidade de Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, 96010-900 Pelotas, RS, Brazil.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Schuch
authors.affiliation: Unidade de Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, 96010-900 Pelotas, RS, Brazil.
authors.forename: Angelita da S
authors.initials: Ada S
authors.lastname: Moreira
authors.affiliation: Unidade de Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, 96010-900 Pelotas, RS, Brazil.
authors.forename: Marta
authors.initials: M
authors.lastname: Amaral
authors.affiliation: Unidade de Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, 96010-900 Pelotas, RS, Brazil.
authors.forename: Tiago
authors.initials: T
authors.lastname: Collares
authors.affiliation: Unidade de Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, 96010-900 Pelotas, RS, Brazil.
authors.forename: Claire T
authors.initials: CT
authors.lastname: Vendrusculo
authors.affiliation: Unidade de Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, 96010-900 Pelotas, RS, Brazil.
authors.forename: Alan J A
authors.initials: AJ
authors.lastname: McBride
authors.affiliation: Unidade de Biotecnologia, Centro de Desenvolvimento Tecnológico, Universidade Federal de Pelotas, 96010-900 Pelotas, RS, Brazil.
authors.forename: Odir A
authors.initials: OA
authors.lastname: Dellagostin
mesh_terms: D000276:Adjuvants, Immunologic / Q000494:pharmacology*; D000818:Animals; D000917:Antibody Formation / Q000187:drug effects; D000942:Antigens, Bacterial / Q000276:immunology; D001428:Bacterial Vaccines / Q000276:immunology*; D016466:CHO Cells; D016923:Cell Death / Q000187:drug effects; D006224:Cricetinae; D003412:Cricetulus; D004195:Disease Models, Animal; D005260:Female; D006813:Humidity; D056724:Immunity, Humoral / Q000187:drug effects; D007114:Immunization; D007921:Leptospira interrogans / Q000502:physiology; D007922:Leptospirosis / Q000276:immunology* / Q000382:microbiology / Q000517:prevention & control*; D008647:Mesocricetus; D009584:Nitrogen / Q000032:analysis; D011135:Polysaccharides, Bacterial / Q000276:immunology* / Q000494:pharmacology; D019289:Pyruvic Acid / Q000032:analysis; D022223:Vaccines, Subunit / Q000276:immunology*
chemical_list: D000276:Adjuvants, Immunologic; D000942:Antigens, Bacterial; D001428:Bacterial Vaccines; D011135:Polysaccharides, Bacterial; D022223:Vaccines, Subunit; D019289:Pyruvic Acid; D009584:Nitrogen; C002563:xanthan gum