Evaluation of different ways of presenting LipL32 to the immune system with the aim of developing a recombinant vaccine against leptospirosis.
ABSTRACT Leptospirosis, caused by bacteria of the genus Leptospira, is a direct zoonosis with wide geographical distribution. The implications in terms of public health and the economical losses caused by leptospirosis justify the use of a vaccine against Leptospira in human or animal populations at risk. In this study, we used the external membrane protein LipL32 as a model antigen, as it is highly immunogenic. The LipL32 coding sequence was cloned into several expression vectors: (i) pTarget, to create a DNA vaccine; (ii) pUS973, pUS974, and pUS977 for expression in BCG (rBCG); and (iii) pAE, to express the recombinant protein in Escherichia coli, for a subunit vaccine. Mice were immunized with the various constructs, and the immune response was evaluated. The highest humoral immune response was elicited by the subunit vaccine (rLipL32). However, with rBCG, the titer was still rising at the end of the experiment. The serum of vaccinated animals was able to recognize LipL32 on the membrane of the Leptospira, detected by indirect immunofluorescence. A monoclonal antibody anti-LipL32 was shown to inhibit the growth of Leptospira in vitro, indicating potential protection induced by the LipL32 antigen.
- SourceAvailable from: Hygia Guerreiro[show abstract] [hide abstract]
ABSTRACT: There is an urgent need for development of new serodiagnostic strategies for leptospirosis, an emerging zoonosis with worldwide distribution. We have evaluated the diagnostic utility of five recombinant antigens in enzyme-linked immunosorbent assays (ELISAs) for serodiagnosis of leptospirosis. Sera from 50 healthy residents of a high-incidence region were used to determine cutoff values for 96% specificity. In paired sera from 50 cases of leptospirosis confirmed by the microscopic agglutination test, immunoglobulin G (IgG) but not IgM reacted with the recombinant leptospiral proteins. The recombinant LipL32 IgG ELISA had the highest sensitivities in the acute (56%) and convalescent (94%) phases of leptospirosis. ELISAs based on recombinant OmpL1, LipL41, and Hsp58 had sensitivities of 16, 24, and 18% during the acute phase and 72, 44, and 32% during convalescence, respectively. Compared to sera from healthy individuals, patient sera did not react significantly with recombinant LipL36 (P > 0.05). Recombinant LipL32 IgG ELISA demonstrated 95% specificity among 100 healthy individuals, and specificities ranging from 90 to 97% among 30 dengue patients, 30 hepatitis patients, and 16 patients with diseases initially thought to be leptospirosis. Among 39 Venereal Disease Research Laboratory test-positive individuals and 30 Lyme disease patients, 13 and 23% of sera, respectively, reacted positively with the rLipL32 antigen. These findings indicate that rLipL32 may be an useful antigen for the serodiagnosis of leptospirosis.Journal of Clinical Microbiology 10/2001; 39(9):3303-10. · 4.07 Impact Factor
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ABSTRACT: BCG, a live attenuated tubercle bacillus, is the most widely used vaccine in the world and is also a useful vaccine vehicle for delivering protective antigens of multiple pathogens. Extrachromosomal and integrative expression vectors carrying the regulatory sequences for major BCG heat-shock proteins have been developed to allow expression of foreign antigens in BCG. These recombinant BCG strains can elicit long-lasting humoral and cellular immune responses to foreign antigens in mice.Nature 07/1991; 351(6326):456-60. · 38.60 Impact Factor
Article: Leptospirosis.[show abstract] [hide abstract]
ABSTRACT: Leptospirosis is a worldwide zoonotic infection with a much greater incidence in tropical regions and has now been identified as one of the emerging infectious diseases. The epidemiology of leptospirosis has been modified by changes in animal husbandry, climate, and human behavior. Resurgent interest in leptospirosis has resulted from large outbreaks that have received significant publicity. The development of simpler, rapid assays for diagnosis has been based largely on the recognition that early initiation of antibiotic therapy is important in acute disease but also on the need for assays which can be used more widely. In this review, the complex taxonomy of leptospires, previously based on serology and recently modified by a genotypic classification, is discussed, and the clinical and epidemiological value of molecular diagnosis and typing is also evaluated.Clinical Microbiology Reviews 05/2001; 14(2):296-326. · 17.31 Impact Factor