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Identification of genus-specific epitopes on the outer membrane complexes of Chlamydia trachomatis and Chlamydia
R R Mondesire1, I W Maclean, P E Shewen
1Department of Veterinary Microbiology, University of Guelph, Ontario, Canada.
Abstract:
Polyclonal and monoclonal antibodies were used to study the immunogenic and antigenic characteristics of chlamydiae. We focused on the most predominant proteins in the outer membrane complex, the major outer membrane protein (MOMP) and the doublet consisting of proteins of 57 and 62 kilodaltons (57-62 kDa doublet). Immunoblot analyses were performed with chlamydial elementary bodies by using (i) immune sera from sheep which had undergone a recent episode of abortion due to the ovine abortion (OA) strain of C. psittaci, (ii) rabbit hyperimmune anti-C. psittaci (OA) and -C. trachomatis sera, and (iii) monoclonal antibodies to the MOMP of C. trachomatis. The typical pattern of response with polyclonal antisera against heterologous elementary bodies was reactivity with the 57-62 kDa doublet and lipopolysaccharide with weak and sometimes no anti-MOMP activity. Three distinct genus-specific anti-C. trachomatis MOMP monoclonal antibodies showed different patterns of reactivity with the MOMPs of the two immunotypes of C. psittaci and C. trachomatis serovars. Our data confirm the predominance of a genus-specific 57-62 kDa doublet response despite the presence of genus-specific epitopes on the MOMP.
Insights
This study investigated chlamydial outer membrane proteins using antibodies. Researchers found that the 57-62 kDa doublet is a predominant genus-specific antigen, even with genus-specific epitopes on the major outer membrane protein (MOMP).
Area of Science:
- Immunology
- Microbiology
- Protein Chemistry
Background:
- Chlamydiae possess complex outer membrane proteins crucial for immunogenicity and antigenicity.
- The major outer membrane protein (MOMP) and a 57-62 kDa doublet are predominant chlamydial outer membrane components.
Purpose of the Study:
- To characterize the immunogenic and antigenic properties of chlamydial outer membrane proteins.
- To compare the reactivity of polyclonal and monoclonal antibodies against chlamydial antigens.
Main Methods:
- Immunoblot analyses were performed on chlamydial elementary bodies.
- Utilized immune sera from sheep and rabbits, along with monoclonal antibodies targeting C. trachomatis MOMP.
Main Results:
- Polyclonal antisera showed strong reactivity with the 57-62 kDa doublet and lipopolysaccharide, with weak or no anti-MOMP activity.
- Monoclonal antibodies against C. trachomatis MOMP exhibited varied reactivity patterns with different chlamydial immunotypes.
- A predominant genus-specific response to the 57-62 kDa doublet was confirmed.
Conclusions:
- The 57-62 kDa doublet is a significant genus-specific antigen in chlamydiae.
- Despite genus-specific epitopes on MOMP, the 57-62 kDa doublet elicits a more consistent genus-specific immune response.