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Molecular characterization of thermoinduced immunogenic proteins Q1p42 and Hsp15 of Leptospira interrogans.

ABSTRACT: Leptospira interrogans is a mammalian pathogen which must adapt to a range of new environmental conditions including temperature change when it infects new hosts. In vitro studies of organisms cultured at 30 degrees C and shifted to 37 degrees C for 5 to 7 days have confirmed that synthesis of several proteins involved in equine infection is regulated in response to temperature change (J. E. Nally, J. F. Timoney, and B. Stevenson, Infect. Immun. 69:400-404, 2001). In order to specifically identify antigenic proteins upregulated at 37 degrees C, groups of three ponies were immunized with organisms shifted to 37 degrees C for 5 to 7 days or with organisms maintained at 30 degrees C. A lambda ZAP II genomic DNA library was screened with the pool of antisera to organisms shifted to 37 degrees C. Clones reactive with this pool but unreactive with the pool of pony antisera to organisms cultured at 30 degrees C were selected for further analysis. Sequence analysis of the first two clones identified open reading frames for proteins designated Qlp42 and Hsp15. Qlp42 is predicted to be an outer membrane lipoprotein. Its synthesis was upregulated when cultures were shifted from 30 to 37 degrees C and downregulated when cultures were shifted from 37 to 30 degrees C. Although the predicted molecular mass of Qlp42 is 39.8 kDa for the mature protein, Qlp42-specific equine antiserum was reactive with two bands of 30 and 29.5 kDa. Hsp15 is a stress response protein and a member of the Hsp20/alpha-crystallin family. PCR detected homologues of qlp42 and hsp15 in pathogenic serovars of L. interrogans but not in the nonpathogenic Leptospira biflexa. Enzyme-linked immunosorbent assays of antibody in convalescent sera from mares naturally infected with L. interrogans suggest that Qlp42 is expressed during leptospiral infection.

SUBMITTER: Nally JE

PROVIDER: S-EPMC98855 | biostudies-literature | 2001 Dec

REPOSITORIES: biostudies-literature

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Molecular characterization of thermoinduced immunogenic proteins Q1p42 and Hsp15 of Leptospira interrogans.

Nally J E JE Artiushin S S Timoney J F JF

Infection and immunity 20011201 12

Leptospira interrogans is a mammalian pathogen which must adapt to a range of new environmental conditions including temperature change when it infects new hosts. In vitro studies of organisms cultured at 30 degrees C and shifted to 37 degrees C for 5 to 7 days have confirmed that synthesis of several proteins involved in equine infection is regulated in response to temperature change (J. E. Nally, J. F. Timoney, and B. Stevenson, Infect. Immun. 69:400-404, 2001). In order to specifically identi ...[more]

PMID: 11705941

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Project description:Leptospira interrogans causes a variety of clinical syndromes in animals and humans. Although much information has accumulated on the importance of leptospiral lipopolysaccharide in protective antibody responses, relatively little is known about proteins that participate in immune responses. Identification of those proteins induced only in the host is particularly difficult. Using a novel double-antibody screen designed to identify clones in a gene library of L. interrogans serovar Pomona expressing host-inducible proteins, we have characterized a gene (lk75.3) encoding a sphingomyelinase-like preprotein of 648 amino acids with cytotoxic activity for equine pulmonary endothelial cells and weak hemolytic activity for equine and rabbit erythrocytes. lk73.5 was found as a single gene copy in all serovars of L. interrogans but not in other Leptospira spp. except L. inadai. The open reading frame (ORF) for Lk73.5 is followed by another partially homologous sequence containing an ORF (sph-like 2) for a 28.7-kDa peptide. Lk73.5 and Sph-like 2 share 95.1 and 97.7% amino acid identity with putative sphingomyelinases Sph2 and Sph1 (N terminus) from L. interrogans serovar Lai (S.-X. Ren, G. Fu, X.-G. Jiangk, R. Zeng, Y.-G. Miao, H. Xu, Y.-X. Zhang, H. Xiong, G. Lu, L.-F. Lu, H.-Q. Jiang, J. Jia, Y.-F. Tu, J.-X. Jiang, W.-Y. Gu, Y.-Q. Zhang, Z. Cai, H.-H. Sheng, H.-F. Yin, Y. Zhang, G.-F. Zhu, M. Wank, H.-L. Huangk, Z. Qian, S.-Y. Wang, Wei Ma, Z.-J. Yao, Y. Shen, B.-Q. Qiang, Q.-C. Xia, X.-K. Guo, A. Danchinq, I. S. Girons, R. L. Somerville, Y.-M. Wen, M.-H. Shik, Z. Chen, J.-G. Xuk, and G.-P. Zhao, Nature 422:88-893, 2003). Substantial homologies to sphingomyelinases from other leptospiras and other bacteria are also present. Lk73.5 was not detected in leptospiras cultured at 30 or 37 degrees C. The recombinant protein reacted strongly with sera from recently infected mares but not with sera from horses vaccinated with commercial pentavalent bacterin. The host-inducible immunogenic Lk73.5 should have value in distinguishing vaccine from infection immune response.

Dataset Information

Molecular characterization of thermoinduced immunogenic proteins Q1p42 and Hsp15 of Leptospira interrogans.

Publications

Molecular characterization of thermoinduced immunogenic proteins Q1p42 and Hsp15 of Leptospira interrogans.

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