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Antigens recognised by the human immune response to infection with Leptospira interrogans serovar hardjo
A J Chapman1, B Adler, S Faine
1Department of Microbiology, Monash University, Clayton, Australia.
Abstract:
Serum samples from patients infected with Leptospira interrogans serovar hardjo were tested by the microscopic agglutination test (MAT), enzyme immunoassay (EIA) and immunoblotting. There was no apparent correlation between MAT titre and EIA optical density (OD) for individual serum samples, but sequential serum samples produced similar profiles in both tests during the course of an infection. Immunoblotting of hardjo sonicate with patients' sera revealed reactions with a number of bands, in the mol. wt (10(3] range 14.4-95. However, all serum samples reacted with the major 28 x 10(3)-mol. wt sub-unit of hardjo lipopolysaccharide (LPS) and most reacted with a (34.5-35) x 10(3)-mol. wt flagella doublet. Examination of sequential serum samples obtained over a period of about 3 months after infection revealed little change in the antigens detected after the second to third week of infection. Absorption of patients' sera with whole viable leptospires revealed that antibodies to several exposed antigens, including LPS, were produced. Sera which reacted with hardjo flagella also reacted with bands of similar mol. wts in preparations from other serovars.
Insights
This study investigated immune responses to Leptospira interrogans serovar hardjo infection using MAT, EIA, and immunoblotting. Researchers identified key antigens, including lipopolysaccharide (LPS) and flagella, recognized by patient antibodies during infection.
Area of Science:
- Microbiology
- Immunology
- Infectious Diseases
Background:
- Leptospira interrogans serovar hardjo is a significant bacterial pathogen.
- Accurate serological diagnostics are crucial for understanding and managing leptospirosis.
Purpose of the Study:
- To characterize the antibody response to Leptospira interrogans serovar hardjo infection.
- To identify specific antigens recognized by patient sera.
Main Methods:
- Microscopic agglutination test (MAT), enzyme immunoassay (EIA), and immunoblotting were employed.
- Serum samples from infected patients were analyzed.
- Antigenic targets were identified based on molecular weight.
Main Results:
- No direct correlation was found between MAT titre and EIA optical density (OD) for individual samples.
- Sequential samples showed similar immune profiles over time.
- Key antigens recognized included a 28 kDa lipopolysaccharide (LPS) subunit and a 34.5-35 kDa flagella doublet.
Conclusions:
- Antibodies to multiple antigens, including LPS and flagella, are produced during infection.
- Antibody responses to identified antigens are consistent after the third week of infection.
- Cross-reactivity with flagellar antigens was observed across different serovars.