[Study on the immunogenicity of major leptospiral genus-specific protein antigens and the distribution of antigens in different serogroups of Leptospira interrogans].
OBJECTIVE
The determination of antigenicity and immunogenicity of Leptospira interrogans genus-specific outer envelope proteins (OEPs) will offer evidence for developing universal leptospiral genetic engineering vaccine and detection kit.


METHODS
In this study, Ni-NTA affinity chromatography is used to purify the recombinant products rLipL21, rOmpL1/1, rOmpL1/2, rLipL32/1, rLipL32/2, rLipL41/1 and rLipL41/2 expressed by the major genotypes of four leptospiral OEPs of 15 serogroups. SDS-PAGE is applied to examine the expression and purity of the recombinant proteins. Rabbits are intracutaneously immunized with the recombinant proteins to obtain antisera. Microscope agglutination test (MAT) is used to measure the cross inmmunoagglutination titers of antisera. The OMPs of the reference standard strains belonging to 15 serogroups of L. interrogans in China and L. biflexa strain Patoc I are prepared using salt-denature method. By each of the antisera as the first antibody, Western blot assay is established to detect the natural expressions and immunoreactivity of the four OEPs.


RESULTS
The outputs of rLipL21, rLipL32/1, rLipL32/2, rLipL41/1l, rLipL41/2, rOmpL1/1 and rOmpL1/2 are 10%, 40%, 35%, 15%, 10%, 30% and 15%, respectively. Each the purified recombinant proteins shows a single fragment after SDS-PAGE. Each the rabbit antisera displays extensive cross immunoreactivity between the products expressed by different genotypes of the same gene and the MAT titers ranging from 1:2-1:128. All the four OEPs can be detectable in the OEPs preparations. However, LipL21 is found to exist only in L. interrrogans.


CONCLUSIONS
The results of this study indicate that all the four OEPs are superficial genus-specific antigens of Leptospira which can be used as the candidate antigens of leptospiral universal vaccine and detection kit.
Sun
Bai-li
BL
College of Land and Enviromenty Shenyang Agriculture University, Shenyang 110161, China.
Luo
Dong-jiao
DJ
Sun
Jun-de
JD
Yan
Jie
J
D000818:Animals; D000917:Antibody Formation; D000942:Antigens, Bacterial / Q000276:immunology*; D004591:Electrophoresis, Polyacrylamide Gel; D005818:Genetic Engineering; D007114:Immunization; D007921:Leptospira interrogans / Q000145:classification / Q000276:immunology*; D008565:Membrane Proteins; D011817:Rabbits; D011994:Recombinant Proteins / Q000276:immunology*; D012703:Serotyping
D000942:Antigens, Bacterial; D008565:Membrane Proteins; D011994:Recombinant Proteins