Functional and structural mapping of Chlamydia trachomatis species-specific major outer membrane protein epitopes by use of neutralizing monoclonal antibodies

Abstract

Three monoclonal antibodies (MAbs), E4, Ll-4, and L1-24, to the major outer membrane protein (MOMP) of Chiamydia trachomatis were identified that neutralized in vitro the infectivity of members of the Band C-related complex as well as the mouse pneumonitis strain. MAbs L1-4, Ll-24, and E4 gave a strong signal in an indirect immunofluorescence assay and/or Western immunoblot with all serovars of the lymphogranuloma venereum and trachoma biovars and a weak signal with the mouse biovar. In addition, C. psittaci and C. pneumoniae were also weakly recognized by MAbs Ll-4 and Ll-24. As determined by the technique of overlapping peptides, all three MAbs showed reactivity to variable domain (VD) IV of MOMP. While all three MAbs had different recognition patterns, all strongly bound to the peptides TLNPTI and LNPTIA within the species-conserved region of VD IV. MAb E4 also recognized the peptide SATAIF in the subspecies region of VD IV. Peptides corresponding to VY IV of MOMP were synthesized and used in competitive inhibition experiments to determine the functional location of the epitope recognized by these three MAbs. Both the serological and neutralizing activities of MAb E4 were inhibited by the peptides ATAIFDTTTLNPTIAG and FDTTTLNPTIAG; however, none of the peptides made to the VD IV region blocked the neutralizing activity of MAbs L1-4 and Ll-24. Therefore, the neutralizable domain of the epitope recognized by MAb E4 is contiguous and may be an important candidate for inclusion in a subunit vaccine.

A multi‐subunit Chlamydia vaccine inducing neutralizing antibodies and strong IFN‐γ+ CMI responses protects against a genital infection in minipigs

“…Sera from Hirep1+CTH93/CAF01-immunized pigs recognized Sv-specific peptides of SvD, SvE and SvF, all surrounding peptide 30 containing the conserved neutralizing epitope TLNPTIAG. 10,43 In comparison, the B-cell recognition in UV-SvD/CAF01-immunized pigs showed a narrower epitope pattern, with fewer epitopes recognized, however, still including peptide 30.…”

Prediction of the membrane‐spanning β‐strands of the major outer membrane protein of Chlamydia

“…Already in the original paper by Schirmer and Cowan (1993), it was shown that the Hs' algorithm can produce false positives. Immunological studies and immunoelectronmicroscopy, for example, have shown that mice inoculated with Chlamydia produce antibodies against all four VDs of the MOMP (Kuo and Chi 1987;Baehr et al 1988;Baghian et al 1990;Andersen 1991;Peterson et al 1991;Pal et al 1993Pal et al , 1996Pal et al , 1997aPal et al ,b, 2000Qu et al 1993;Villeneuve et al 1994). Like with Neisseria gonorrhoeae only the long loops L2, L3, L5, and L6 of C. trachomatis and C. psittaci have VDs probably reflecting the fact that they are more immunoaccessible (van der Ley et al 1991).…”

Quantitative proteomics reveals metabolic and pathogenic properties of Chlamydia trachomatis developmental forms

“…The C. trachomatis cell envelope Proteins in the C. trachomatis envelope are attractive targets for the development of neutralizing vaccines (Zhang et al, 1987;Peterson et al, 1991;Koehler et al, 1992;Howie et al, 2011). Polymorphic membrane pro- (17) All C. trachomatis L2 proteins quantified were classified into functional categories as described in Experimental procedures.…”