The low-molecular-mass, cysteine-rich outer membrane protein of Chlamydia trachomatis possesses both biovar- and species-specific epitopes.
We isolated, by hydroxylapatite high-performance liquid chromatography, 14- and 15-kilodalton (kDa), cysteine-rich outer membrane proteins from Chlamydia trachomatis TW-5/OT (serovar B) and LGV-434 (serovar L2), respectively. Monoclonal antibodies (MAbs) were generated against the purified proteins, and their specificities were determined by immunoblotting. MAb B-14k recognized an epitope located on the 14-kDa cysteine-rich protein of the TW-5/OT strain and was immunoreactive with a comigrating 14-kDa protein that was common to all trachoma biovar strains, but it did not react with the 15-kDa, cysteine-rich protein of LGV biovar strains. In contrast, MAb L2-15k, which recognized an epitope located on the 15-kDa protein of the LGV-434 strain, reacted with the 15- and 14-kDa, cysteine-rich proteins of both LGV and trachoma biovar strains, but did not react with related proteins of two Chlamydia psittaci strains. Thus, the low-molecular-mass, cysteine-rich outer membrane proteins of C. trachomatis possess antigenic determinants that are both biovar and species specific. Neither MAbB-14k nor MAb L2-15k was reactive by dot-blot assay when viable chlamydiae were used as test antigens, indicating that the cysteine-rich proteins are not accessible to antibody on the native chlamydial cell surface.
Zhang
Y X
YX
Chlamydial Diseases Section, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, Montana 59840.
Watkins
N G
NG
Stewart
S
S
Caldwell
H D
HD
D000907:Antibodies, Bacterial / Q000276:immunology; D000911:Antibodies, Monoclonal / Q000276:immunology; D000918:Antibody Specificity; D000942:Antigens, Bacterial / Q000276:immunology* / Q000302:isolation & purification; D000954:Antigens, Surface / Q000276:immunology; D001425:Bacterial Outer Membrane Proteins / Q000276:immunology* / Q000302:isolation & purification; D002692:Chlamydia trachomatis / Q000276:immunology*; D002851:Chromatography, High Pressure Liquid; D008970:Molecular Weight; D013045:Species Specificity
D000907:Antibodies, Bacterial; D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial; D000954:Antigens, Surface; D001425:Bacterial Outer Membrane Proteins