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author:("cdoda, julio")
1.  The terminal portion of leptospiral immunoglobulin-like protein LigA confers protective immunity against lethal infection in the hamster model of leptospirosis 
Vaccine  2007;25(33):6277-6286.
Subunit vaccines are a potential intervention strategy against leptospirosis, which is a major public health problem in developing countries and a veterinary disease in livestock and companion animals worldwide. Leptospiral immunoglobulin-like (Lig) proteins are a family of surface-exposed determinants that have Ig-like repeat domains found in virulence factors such as intimin and invasin. We expressed fragments of the repeat domain regions of LigA and LigB from Leptospira interrogans serovar Copenhageni. Immunization of Golden Syrian hamsters with Lig fragments in Freund’s adjuvant induced robust antibody responses against recombinant protein and native protein, as detected by ELISA and immunoblot, respectively. A single fragment, LigANI, which corresponds to the six carboxy-terminal Ig-like repeat domains of the LigA molecule, conferred immunoprotection against mortality (67-100%, P <0.05) in hamsters which received a lethal inoculum of L. interrogans serovar Copenhageni. However, immunization with this fragment did not confer sterilizing immunity. These findings indicate that the carboxy-terminal portion of LigA is an immunoprotective domain and may serve as a vaccine candidate for human and veterinary leptospirosis.
PMCID: PMC1994161  PMID: 17629368
Leptospirosis; subunit vaccine; Leptospiral immunoglobulin-like protein; recombinant protein; immunity; antibodies; hamsters
2.  Leptospiral Proteins Recognized during the Humoral Immune Response to Leptospirosis in Humans 
Infection and Immunity  2001;69(8):4958-4968.
Leptospirosis is an emerging zoonosis caused by pathogenic spirochetes belonging to the genus Leptospira. An understanding of leptospiral protein expression regulation is needed to develop new immunoprotective and serodiagnostic strategies. We used the humoral immune response during human leptospirosis as a reporter of protein antigens expressed during infection. Qualitative and quantitative immunoblot analysis was performed using sera from 105 patients from Brazil and Barbados. Sera from patients with other diseases and healthy individuals were evaluated as controls. Seven proteins, p76, p62, p48, p45, p41, p37, and p32, were identified as targets of the humoral response during natural infection. In both acute and convalescent phases of illness, antibodies to lipopolysaccharide were predominantly immunoglobulin M (IgM) while antibodies to proteins were exclusively IgG. Anti-p32 reactivity had the greatest sensitivity and specificity: positive reactions were observed in 37 and 84% of acute- and convalescent-phase sera, respectively, while only 5% of community control individuals demonstrated positive reactions. Six immunodominant antigens were expressed by all pathogenic leptospiral strains tested; only p37 was inconsistently expressed. Two-dimensional immunoblots identified four of the seven infection-associated antigens as being previously characterized proteins: LipL32 (the major outer membrane lipoprotein), LipL41 (a surface-exposed outer membrane lipoprotein), and heat shock proteins GroEL and DnaK. Fractionation studies demonstrated LipL32 and LipL41 reactivity in the outer membrane fraction and GroEL and DnaK in the cytoplasmic fraction, while p37 appeared to be a soluble periplasmic protein. Most of the other immunodominant proteins, including p48 and p45, were localized to the inner membrane. These findings indicate that leptospiral proteins recognized during natural infection are potentially useful for serodiagnosis and may serve as targets for vaccine design.
PMCID: PMC98588  PMID: 11447174

Results 1-2 (2)