Expression of leptospiral immunoglobulin-like protein by Leptospira interrogans and evaluation of its diagnostic potential in a kinetic ELISA.
The search for novel antigens suitable for improved vaccines and diagnostic reagents against leptospirosis led to the identification of LigA and LigB. LigA and LigB expression were not detectable at the translation level but were detectable at the transcription level in leptospires grown in vitro. Lig genes were present in pathogenic serovars of Leptospira, but not in non-pathogenic Leptospira biflexa. The conserved and variable regions of LigA and LigB (Con, VarA and VarB) were cloned, expressed and purified as GST-fusion proteins. Purified recombinant LigA and LigB were evaluated for their diagnostic potential in a kinetic ELISA (KELA) using sera from vaccinated and microscopic agglutination test (MAT)-positive dogs. Sera from vaccinated dogs showed reactivity to whole-cell antigens of leptospires but did not show reactivity in the KELA assay with recombinant antigens, suggesting a lack of antibodies to Lig proteins in the vaccinated animals. The diagnostic potential of recombinant Lig antigens in the KELA assay was evaluated by using 67 serum samples with MAT > or =1600, which showed reactivity of 76, 41 and 35% to rConA, rVarA and rVarB, respectively. These findings suggest that recombinant antigen to the conserved region of LigA and LigB can differentiate between vaccinated and naturally infected animals.
Palaniappan
Raghavan U M
RUM
College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA 2Bacterial Diseases of Livestock Research Unit, National Animal Disease Center, Agricultural Research Service, US Department of Agriculture, Ames, IA 50010, USA 3Department of Chemistry, University of Oklahoma, Norman, OK, USA.
Chang
Yung-Fu
YF
College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA 2Bacterial Diseases of Livestock Research Unit, National Animal Disease Center, Agricultural Research Service, US Department of Agriculture, Ames, IA 50010, USA 3Department of Chemistry, University of Oklahoma, Norman, OK, USA.
Hassan
Fahad
F
College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA 2Bacterial Diseases of Livestock Research Unit, National Animal Disease Center, Agricultural Research Service, US Department of Agriculture, Ames, IA 50010, USA 3Department of Chemistry, University of Oklahoma, Norman, OK, USA.
McDonough
Sean P
SP
College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA 2Bacterial Diseases of Livestock Research Unit, National Animal Disease Center, Agricultural Research Service, US Department of Agriculture, Ames, IA 50010, USA 3Department of Chemistry, University of Oklahoma, Norman, OK, USA.
Pough
Margaret
M
College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA 2Bacterial Diseases of Livestock Research Unit, National Animal Disease Center, Agricultural Research Service, US Department of Agriculture, Ames, IA 50010, USA 3Department of Chemistry, University of Oklahoma, Norman, OK, USA.
Barr
Stephen C
SC
College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA 2Bacterial Diseases of Livestock Research Unit, National Animal Disease Center, Agricultural Research Service, US Department of Agriculture, Ames, IA 50010, USA 3Department of Chemistry, University of Oklahoma, Norman, OK, USA.
Simpson
Kenneth W
KW
College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA 2Bacterial Diseases of Livestock Research Unit, National Animal Disease Center, Agricultural Research Service, US Department of Agriculture, Ames, IA 50010, USA 3Department of Chemistry, University of Oklahoma, Norman, OK, USA.
Mohammed
Hussni O
HO
College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA 2Bacterial Diseases of Livestock Research Unit, National Animal Disease Center, Agricultural Research Service, US Department of Agriculture, Ames, IA 50010, USA 3Department of Chemistry, University of Oklahoma, Norman, OK, USA.
Shin
Sang
S
College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA 2Bacterial Diseases of Livestock Research Unit, National Animal Disease Center, Agricultural Research Service, US Department of Agriculture, Ames, IA 50010, USA 3Department of Chemistry, University of Oklahoma, Norman, OK, USA.
McDonough
Patrick
P
College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA 2Bacterial Diseases of Livestock Research Unit, National Animal Disease Center, Agricultural Research Service, US Department of Agriculture, Ames, IA 50010, USA 3Department of Chemistry, University of Oklahoma, Norman, OK, USA.
Zuerner
Richard L
RL
College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA 2Bacterial Diseases of Livestock Research Unit, National Animal Disease Center, Agricultural Research Service, US Department of Agriculture, Ames, IA 50010, USA 3Department of Chemistry, University of Oklahoma, Norman, OK, USA.
Qu
Jiaxin
J
College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA 2Bacterial Diseases of Livestock Research Unit, National Animal Disease Center, Agricultural Research Service, US Department of Agriculture, Ames, IA 50010, USA 3Department of Chemistry, University of Oklahoma, Norman, OK, USA.
Roe
Bruce
B
College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA 2Bacterial Diseases of Livestock Research Unit, National Animal Disease Center, Agricultural Research Service, US Department of Agriculture, Ames, IA 50010, USA 3Department of Chemistry, University of Oklahoma, Norman, OK, USA.
D000595:Amino Acid Sequence; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D000942:Antigens, Bacterial / Q000276:immunology*; D001428:Bacterial Vaccines / Q000276:immunology; D004285:Dogs; D004797:Enzyme-Linked Immunosorbent Assay; D007921:Leptospira interrogans / Q000276:immunology*; D007922:Leptospirosis / Q000175:diagnosis*; D008969:Molecular Sequence Data; D014176:Protein Biosynthesis; D012698:Serologic Tests; D014158:Transcription, Genetic; D014611:Vaccination; D014614:Vaccines, Synthetic / Q000276:immunology
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001428:Bacterial Vaccines; C487006:LigB-m protein, Leptospira interrogans; D014614:Vaccines, Synthetic