Identification of immunoreactive proteins of Chlamydia trachomatis by Western blot analysis of a two-dimensional electrophoresis map with patient sera.
Western blots of two-dimensional electrophoretic maps of proteins from Chlamydia trachomatis were probed with sera from 17 seropositive patients with genital inflammatory disease. Immunoblot patterns (comprising 28 to 2 spots, average 14.8) were different for each patient; however, antibodies against a spot-cluster due to the chlamydia-specific antigen outer membrane protein-2 (OMP2) were observed in all sera. The next most frequent group of antibodies (15/17; 88%) recognized the hsp60 GroEL-like protein, described as immunopathogenic in chlamydial infections. Reactivity to the major surface-exposed and variable antigen major outer membrane protein (MOMP) was observed at a relatively lower frequency (13/17; 76%). The hsp70 DnaK-like protein was also frequently recognized (11/17; 64.7%) in this patient group. Besides the above confirmatory findings, the study detected several new immunoreactive proteins, with frequencies ranging from 11/17 to 1/17. Some were characterized also by N-terminal amino acid sequencing and homology searches. Amongst these were a novel outer membrane protein (OmpB) and, interestingly, five conserved bacterial proteins: four (23%) sera reacted with the RNA polymerase alpha-subunit, five (29%) recognized the ribosomal protein S1, eight (47%) the protein elongation factor EF-Tu, seven (41%) a putative stress-induced protease of the HtrA family, and seven sera (41%) the ribosomal protein L7/L12. Homologs of the last two proteins were shown to confer protective immunity in other bacterial infections. The data show that immunological sensitization processes commonly thought to play a role in chlamydial pathogenicity may be sustained not only by the hsp60 GroEl-like protein, but also by other conserved bacterial antigens, some of which may be also considered as potential vaccine candidates.
Sanchez-Campillo
M
M
IRIS Research Centre, Chiron Vaccines, Siena, Italy.
Bini
L
L
Comanducci
M
M
Raggiaschi
R
R
Marzocchi
B
B
Pallini
V
V
Ratti
G
G
D000328:Adult; D000595:Amino Acid Sequence; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood / Q000276:immunology*; D001426:Bacterial Proteins / Q000276:immunology*; D015153:Blotting, Western / Q000379:methods; D002690:Chlamydia Infections / Q000097:blood* / Q000382:microbiology; D002692:Chlamydia trachomatis / Q000276:immunology*; D002522:Chlorocebus aethiops; D015180:Electrophoresis, Gel, Two-Dimensional / Q000379:methods; D005260:Female; D006801:Humans; D008969:Molecular Sequence Data; D014709:Vero Cells
D000907:Antibodies, Bacterial; D001426:Bacterial Proteins