Evaluation of a synthetic peptide based species specific EIA kit for detection of antibodies to Chlamydia trachomatis with clinical specimens

Abstract

We have evaluated a new kit, PEPTIDE Chlamydia (Meiji Milk Products Co., Ltd, Tokyo), for detecting species specific antibodies to Chlamydia trachomatis with synthetic peptide as an antigen. Serum samples from women with C. trachomatis cervicitis (n = 45), healthy pregnant women (n = 100), and children suffering from C. pneumoniae lower respiratory tract infection (n = 9) were used. We have measured the serum IgG or IgA antibodies to C. trachomatis of those sera with PEPTIDE, Sero IPALIZA Chlamydia (Savyon Diagnostics, Israel), and HITAZYME Chlamydia (Hitachi Chemical Co., Ltd, Hitachi). Serum samples with discrepant results were further analyzed by a microimmunofluorescence test and immunoblotting (western blotting). IgG and IgA serum positive rate to C. trachomatis of sera from women with C. trachomatis cervicitis were similar in three kits, that is, 91% and 80% in PEPTIDE, 89% and 82% in Sero IPALIZA, and 84% and 76% in HITAZYME, respectively. IgG and IgA serum positive rate to C. trachomatis of sera from healthy pregnant women were 18% and 9% in PEPTIDE, 12% and 15% in Sero IPALIZA, and 15% and 13% in HITAZYME, respectively. Serum antibodies to C. trachomatis in serum samples from children with C. pneumoniae infection were all negative in PEPTIDE, but falsely positive in several cases in Sero IPALIZA or HITAZYME. In sera with discrepant results, PEPTIDE gave more identical results with a micro-IF test and immunoblotting analysis than Sero IPALIZA or HITAZYME. These results indicate that PEPTIDE is an useful kit to detect more species specific antibodies to Chlamydia trachomatis than former kits.