ANALYSIS OF THE HUMORAL IMMUNE-RESPONSE TO CHLAMYDIA OUTER-MEMBRANE PROTEIN-2

The humoral immune response to Chlamydia outer membrane protein 2 (Omp 2) was studied. Omp2 is a highly genus-conserved structural protein of all Chlamydia species, containing a variable N-terminal fragment. To analyze where the immunogenic parts were localized, seven highly purif ied truncated fusion proteins constituting different regions of the pr otein were produced (Chlamydia pneumoniae-Omp2(aa23-aa93), Chlamydia p sittaci-Omp2(aa23-aa94), and Chlamydia trachomatis-Omp2(aa23-aa84, aa8 7-aa547, aa23-aa182, aa167-aa434, aa420-aa547)) BY an enzyme-linked im munosorbent assay with serologically defined patient sera, Omp2 was fo und to be a major immunogen of both C. pneumoniae and C. trachomatis i nfections (P much less than 0.0001). The humoral immune responses were not confined to any particular region of the Omp2 protein, and no spe cies-specific anti-Omp2 immunoglobulins were detected.