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Detection of surface-exposed epitopes on Chlamydia trachomatis by immune electron microscopy
B A Collett1, W J Newhall, R A Jersild
1Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis 46223.
Journal of General Microbiology
|January 1, 1989
Summary
Chlamydia trachomatis outer membrane proteins were studied using immune electron microscopy. Major outer-membrane protein (MOMP) is a surface antigen on both elementary bodies (EBs) and reticulate bodies (RBs), while lipopolysaccharide (LPS) is exposed on RBs but not EBs.
Area of Science:
- Microbiology
- Immunology
- Cell Biology
Background:
- Chlamydia trachomatis is an obligate intracellular bacterium with distinct morphological forms: elementary bodies (EBs) and reticulate bodies (RBs).
- The bacterial cell surface, particularly outer membrane components, plays a crucial role in host-cell interaction and immune evasion.
Purpose of the Study:
- To investigate the surface exposure of Chlamydia trachomatis outer membrane components in different developmental stages.
- To characterize the immunogenic epitopes on major outer-membrane protein (MOMP) and lipopolysaccharide (LPS) of C. trachomatis serovars.
Main Methods:
- Immune electron microscopy was employed using monoclonal antibodies targeting various chlamydial outer membrane proteins.
- Two C. trachomatis serovars (lymphogranuloma venereum biovar L2/434/Bu and trachoma biovar F/UW-6/Cx) were analyzed at both EB and RB stages.
Main Results:
- Major outer-membrane protein (MOMP) epitopes, including genus, species, and serovar-reactive ones, were exposed on both EB and RB surfaces, with three exceptions.
- Genus-specific lipopolysaccharide (LPS) epitopes were detected on RBs but were inaccessible on the EB surface.
- Antibodies against 60 kDa and 12 kDa cysteine-rich outer membrane proteins did not react with surface epitopes on either form.
Conclusions:
- MOMP is a significant surface antigen present on both developmental forms of C. trachomatis.
- Lipopolysaccharide (LPS) epitopes are surface-exposed on reticulate bodies (RBs) but become masked upon conversion to the infectious elementary body (EB) form.