Humoral immune response to plasmid protein pgp3 in patients with Chlamydia trachomatis infection.
We identified, by two-dimensional electrophoretic analysis and microsequencing, a protein of Chlamydia trachomatis elementary bodies which corresponds to the polypeptide (pgp3) encoded by open reading frame 3 (ORF3). Amino acid analysis showed that the first residue (Gly) found in the native protein is the one encoded by the second ORF3 codon, implying a typical bacterial removal of the first Met residue. Relatively large amounts of recombinant pgp3 (r-pgp3) in a stable, water-soluble form were obtained by overexpressing ORF3 in Escherichia coli and purifying the product from periplasmic extracts under nondenaturing conditions. These r-pgp3 preparations allowed specific detection of anti-pgp3 antibodies by enzyme-linked immunosorbent assay. Analysis of a group of 170 sera from healthy blood donors and from patients who were seropositive or -negative for C. trachomatis and Chlamydia pneumoniae showed that an immune response to pgp3 occurs in the majority (ca. 81%) of patients with sexually transmitted diseases who are seropositive for C. trachomatis and generally correlates with the response to cell surface antigens. No reaction between r-pgp3 and C. pneumoniae-positive sera was detected.
Comanducci
M
M
Immunobiological Research Institute Siena, Italy.
Manetti
R
R
Bini
L
L
Santucci
A
A
Pallini
V
V
Cevenini
R
R
Sueur
J M
JM
Orfila
J
J
Ratti
G
G
D000595:Amino Acid Sequence; D000907:Antibodies, Bacterial / Q000097:blood*; D000917:Antibody Formation; D000942:Antigens, Bacterial / Q000276:immunology*; D001426:Bacterial Proteins / Q000276:immunology*; D001483:Base Sequence; D002690:Chlamydia Infections / Q000276:immunology*; D002692:Chlamydia trachomatis / Q000235:genetics / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D004926:Escherichia coli / Q000235:genetics; D005260:Female; D005831:Genital Diseases, Female / Q000276:immunology; D006801:Humans; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics; D010957:Plasmids / Q000235:genetics; D011994:Recombinant Proteins / Q000276:immunology; D012488:Salpingitis / Q000276:immunology
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D011994:Recombinant Proteins; C082169:pgp3 protein, Chlamydia