Characterization of the ompL1 gene of pathogenic Leptospira species in China and cross-immunogenicity of the OmpL1 protein
Authors: Haiyan Dong
Dexter Sun
Yafei Mao
Jie Yan
Ye Hu
Feng Xue
David M Ojcius
Journal: BMC Microbiology (2008)
Discipline: MICROBIOLOGY
Keywords: leptospirosis; OmpL1; antigen; vaccine; serodiagnostic methods
Affiliations: Division of Basic Medical Microbiology, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital of Medical College, Zhejiang University, Hangzhou Zhejiang, PR China. 

Abstract:  Background: The usefulness of available vaccine and serological tests for leptospirosis is limited by the low cross-reactivity of antigens from numerous serovars of pathogenic Leptospira spp. Identification of genus-specific protein antigens (GP-Ag) of Leptospira would be important for development of universal vaccines and serodiagnostic methods. OmpL1, a transmembrane porin of pathogenic leptospires, was identified as a possible GP-Ag, but its sequence diversity and immune cross-reactivity among different serovars of pathogenic leptospires remains largely unknown. Results: PCR analysis demonstrated that the ompL1 gene existed in all 15 official Chinese standard strains as well as 163 clinical strains of pathogenic leptospires isolated in China. In the standard strains, the ompL1 gene could be divided into three groups (ompL1/1, ompL1/2 and ompL1/3) according to their sequence identities. Immune electron microscopy demonstrated that all products of the different gene types of ompL1 are located on the surface of leptospires. The microscopic agglutination test revealed extensive yet distinct cross-immunoagglutination among the antisera against recombinant OmpL1 (rOmpL1) and leptospiral strains belonging to different ompL1 gene types. These cross-immunoreactions were further verified by ELISAs using the OmpL1 proteins as the coated antigens in serum samples from 385 leptospirosis patients. All the antisera against rOmpL1 proteins could inhibit L. interrogans strain Lai from adhering to J774A.1 cells. Furthermore, immunization of guinea pigs with each of the rOmpL1 proteins could cause cross-immunoprotection against lethal challenge with leptospires from different ompL1 gene types. Conclusion: Three types of the ompL1 gene are present in pathogenic leptospires in China. OmpL1 is an immunoprotective GP-Ag which should be considered in the design of new universal vaccines and serodiagnostic methods against leptospirosis. 

Retracted: No

PubPeer comments:
 Figure 3. It seems like there is a splice. Contrast enhanced. ![file] Could the authors please check? , 
 #1 Dear Edentulina Martensi, Thank you for your comment. We will check the data soon. Jie Yan , 
 Figure 4. ![file] Figure 1D from [Lei Zhang et al, 2012] ![file] Much more similar than expected. , 
 in addition to #3, it seems there is a splice in Fig. 4 both in OMPL1 1 and OMPL1 2 between lane numbers 5 and 6, could the authors provide the original gel? , 
 #1 The original comment about Fig 3 is grossly misleading. In the published images (at the journal or at PubMed), there is a clear separation between lanes 5 and 6, making abundantly clear that the left and right halves are separate, and each half has its own MW markers. In the  contrast enhanced version posted in comment #1, this fact has been entirely obscured by the commenter s manipulation. This is clearly deceptive, intentionally or not. Link to HTML figure: https: bmcmicrobiol.biomedcentral.com articles 10.1186 1471-2180-8-223 figures 3 Image: ![file] , 
 #5 I think perhaps the commenter in #1 is referring to a horizontal splice. Iu2019m not sure I agree with them that this looks like a splice, but there appears to be a straight horizontal line across a portion the image. *** Inverted image ![file] , 
 #6 If that is what post #1 intended to highlight, then it reinforces the need for commenters to use words to describe their concerns. Regarding the horizontal line: it continues across the panel, so that it also affects the bands in lanes 7-9. There are also other horizontal lines in the left panel, below the 31 kD marker position. All of these are likely to be due to compression artifacts or other image degradation, and hence they are not noteworthy. , 
 I m sorry if my first comment was misunderstood, I should have placed one more arrow like #6 has done. At first I thought that was a compression artifact too, but there is a very strong change in colour near that line; for that reason I asked the authors if they could check. , 
 There are some unexpected similarities between some blots in [Ruan et al, 2008] Figure 3 from that paper: ![file] Figure 4 from this one: ![file] Compare (yellow box): ![file] , 
 Figure 3 has some unexpectedly similar features in common with [Ruan et al, 2008] ![file] ![file] , 
 Picking up from previous comment #9, red boxes added. ![file] ,