FIG 1.

CT618 antibody-reactive region 190 (CT618_ARR190). (A) Complete ARR190 alignment of the putative inclusion membrane protein CT618 (locus tag CT_618 of C. trachomatis strain D/UW-3/CX) with the homologs of the remaining eight Chlamydia species. The alignment includes the antibody-reactive polymorphic region bracketed by regions conserved among the nine chlamydial species. Numbers within vertical lines correspond to amino acid residue numbers of each species. Numbers on top of the alignment indicate approximate residue numbers of the Ctr_CT618 protein. The designation antibody-reactive region 190 (ARR190) is derived from the approximate central residue of the species-specific antibody determining region of the Ctr_CT618. (B) Antibody reactivity of CT618_ARR190 peptides with Chlamydia monospecies-specific antisera pooled from 9 to 50 mice. Peptides are named for Chlamydia species specificity (Cab, Cps, etc.), followed by strain and protein designation, and amino acid positions of the peptide in the respective proteins. Average reactivity of three repeats of each peptide from a high-stringency ELISA (interassay coefficient of variation [CV] = 11.2%, intra-assay CV = 8.5%). Boldface peptide signals indicate the specific reactivity with homologous sera. All signals of positive serum pools are significantly above background (P < 10⁻³; one-tailed Student t test). Boldface peptides show strong species-specific reactivity with homologous sera. Cross-reactivity with Cps-specific sera is evident for the strongly reactive Cab peptide Cab_S26/3_CT618_187-226.