ANTIBODY-RESPONSE TO B-CELL EPITOPES OF CHLAMYDIA-TRACHOMATIS 60-KDA HEAT-SHOCK PROTEIN AND CORRESPONDING MYCOBACTERIAL AND HUMAN PEPTIDES IN INFANTS WITH CHLAMYDIAL PNEUMONITIS

To study antibody response to the hypersensitivity protein B of Chlamy dia trachomatis, also known as the 60-kDa heat-shock protein (hsp60), epitope scanning was done over the entire protein. Human sera with ant ibodies to C. trachomatis identified 5 major antigenic regions (peptid es 2, 5, 9, 17, and 21) and several minor regions (peptides 34-37, 39, 50, and 59-62). Clear-cut IgG antibody responses to chlamydial peptid e 2 (YNEEARKKIQKGVKT) and a corresponding mycobacterial peptide (YDEEA RRGLERGLNA) were found in 8 of 16 infants with chlamydial pneumonitis and in 1 of 18 controls. Peptide 50 (RLAKLSGGVAVIRVG) showed an 80% id entity with its human counterpart (RLAKLSDGVAVLKVG), which was derived from human mitochondrial protein P1, but specific antipeptide antibod y responses were found in 3 of 16 cases only. In summary, both IgG ant ibody response to C. trachomatis hsp60 and occasional autoantibody for mation in infants with chlamydial pneumonitis were found.