The terminal portion of leptospiral immunoglobulin-like protein LigA confers protective immunity against lethal infection in the hamster model of leptospirosis.
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.
Silva
Everton F
EF
Gonçalo Moniz Research Centre, Oswaldo Cruz Foundation, Brazilian Ministry of Health, Salvador, Brazil.
Medeiros
Marco A
MA
McBride
Alan J A
AJ
Matsunaga
Jim
J
Esteves
Gabriela S
GS
Ramos
João G R
JG
Santos
Cleiton S
CS
Croda
Júlio
J
Homma
Akira
A
Dellagostin
Odir A
OA
Haake
David A
DA
Reis
Mitermayer G
MG
Ko
Albert I
AI
D000818:Animals; D001426:Bacterial Proteins / Q000276:immunology*; D001428:Bacterial Vaccines / Q000008:administration & dosage / Q000276:immunology*; D006224:Cricetinae; D004195:Disease Models, Animal; D004334:Drug Administration Schedule; D007136:Immunoglobulins / Q000737:chemistry; D007919:Leptospira / Q000276:immunology* / Q000378:metabolism; D007922:Leptospirosis / Q000276:immunology* / Q000517:prevention & control*; D008647:Mesocricetus / Q000276:immunology* / Q000382:microbiology; D013997:Time Factors
D001426:Bacterial Proteins; D001428:Bacterial Vaccines; D007136:Immunoglobulins