COMPARISON OF CHLAMYDIA-PNEUMONIAE ISOLATES BY WESTERN-BLOT (IMMUNOBLOT) ANALYSIS AND DNA-SEQUENCING OF THE OMP-2 GENE

The 60-kDa cysteine rich outer membrane protein gene (omp 2) from nine Chlamydia pneumoniae isolates (TW-183, CM-1, CWL-50, CWL-O11, IOL-207 , FIL, Kajaani-6, Helsinki-12 and Parjaanonen) was amplified by PCR an d sequenced from positions 1 to 580. In contrast to the sequence diffe rences previously observed in this gene in other chlamydial species, a ll nine C. pneumoniae isolates were 100% identical. However, when sera from C. pneumoniae microimmunofluorescence-positive patients (with cl inical signs of persistent cough or asthma) were immunoblotted against five C. pneumoniae isolates, distinct antigenic differences were obse rved. TW-183 was characterized by major bands at 35 and 43 kDa. In con trast, the other four isolates tested produced similar, though not ide ntical, immunoblot profiles, characterized by strong bands at 18, 25, 29, 40, 46, and 53 kDa. These data support the fact that significant d ifferences do exist between C. pneumonine isolates, but unlike the cas e,vith other chlamydial species, these differences do not reside in ei ther of the commonly studied outer membrane protein genes, omp 1 or om p 2.