Disease relevance of ompA

• The pathogen was identified in a patient with severe pelvic inflammatory disease (PID) by sequence analysis of the ompA gene [1].
• The ompA gene in Chlamydia trachomatis differs in phylogeny and rate of evolution from other regions of the genome [2].
• One cluster included all Chlamydia trachomatis ompA alleles (trachoma group) [3].
• The Sawyer runs test, compatibility matrices, and index of association analyses provided substantial evidence that there has been a history of intragenic recombination at ompA including one instance of interspecies recombination between the C. trachomatis mouse pneumonitis strain and the C. pneumoniae horse N16 strain [4].
• Lymphogranuloma Venereum Prevalence in Sweden among Men Who Have Sex with Men and Characterization of Chlamydia trachomatis ompA Genotypes [5].

High impact information on ompA

• The nucleotide sequences of the major outer membrane protein gene products were identical and unique for each of 15 culture-negative, PCR-positive concordant partnerships [6].
• Immunogenicity of a chimeric peptide corresponding to T helper and B cell epitopes of the Chlamydia trachomatis major outer membrane protein [7].
• The chlamydial major outer membrane protein (MOMP) is thought to play an important role in the development of protective immunity against chlamydial infection, and is therefore considered to be a promising candidate antigen in the development of a trachoma vaccine [8].
• Identification and characterization of T helper cell epitopes of the major outer membrane protein of Chlamydia trachomatis [8].
• These results indicate that a specific high-mannose type oligosaccharide linked to the major outer membrane protein of C. trachomatis mediates attachment and infectivity of the organism to HeLa cells [9].

Chemical compound and disease context of ompA

• A recombinant Chlamydia trachomatis major outer membrane protein binds to heparan sulfate receptors on epithelial cells [10].
• Monoclonal antibodies (MAb) specific for Chlamydia trachomatis lipopolysaccharide (LPS) and major outer membrane protein (MOMP) were used for immunoelectron microscopy analysis [11].
• The GPIC agent was characterized by analysis of outer membrane proteins, which indicated that the GPIC agent possessed a major outer membrane protein (MOMP), with a molecular mass of 39 kilodaltons (kDa), and a 61-kDa protein, analogous to cysteine-rich 60-kDa proteins or doublets of Chlamydia trachomatis strains [12].
• The major outer membrane protein (MOMP) of Chlamydia trachomatis was determined to be a glycoprotein on the basis of susceptibility to glycosidase digestion and the presence of carbohydrate by staining and radiolabeling [13].
• Binding of the glycan of the major outer membrane protein of Chlamydia trachomatis to HeLa cells [14].

Biological context of ompA

• Strains of Chlamydia trachomatis are classified into serovars based on nucleotide sequence differences in ompA, the gene that encodes the major outer membrane protein [2].
• We found, however, no evidence of recombination within or between any of the sampled regions around the C. trachomatis genome apart from ompA [2].
• Phylogenetic characterization of strains based on ompA, however, results in serovar groupings that are inconsistent with the distinguishing features of C. trachomatis pathobiology, e.g., tissue tropisms and disease presentation [2].
• Furthermore, certain ompA genotype variants of the dominant serotypes were highly prevalent among MSM, and the reason for this is discussed [5].
• While much of our knowledge about its genetic diversity comes from serotyping or ompA genotyping, no quantitative assessment of genetic diversity within serotypes has been performed [15].

Anatomical context of ompA

• Recurrent mutations that disrupt T cell epitopes in the major outer membrane protein in clinical isolates and the reduced transcription of HLA genes by infected cells may be evidence for pathogen evasion of protective immune responses [16].
• Expression of chlamydial lipopolysaccharide (LPS), major outer membrane protein (MOMP), and elementary body (EB) antigens was studied by gold labeling immunoelectron microscopy on 6 synovial membrane and 2 synovial fluid (SF) pellet samples from 6 patients with Chlamydia-associated arthritis [17].
• Dendritic cells pulsed with a recombinant chlamydial major outer membrane protein antigen elicit a CD4(+) type 2 rather than type 1 immune response that is not protective [18].
• Eight hybridomas which were specific for an identical peptide epitope (AGLQND) in serovar C major outer membrane protein variable domain I were identified [19].
• High-level expression of Chlamydia psittaci major outer membrane protein in COS cells and in skeletal muscles of turkeys [20].

Associations of ompA with chemical compounds

• In contrast, MAb reactive against non-immunoaccessible subspecies- or species-specific major outer membrane protein epitopes or against an immunoaccessible genus-specific epitope located on chlamydial lipopolysaccharide did not protect mice from toxic death or neutralize infectivity of the parasite for monkey eyes [21].
• The major outer membrane protein of the L2 serovar is an acidic protein with a pI of ca. 5. It contains three cysteine residues that allow it to form a disulfide-linked proteinaceous network responsible for the characteristic rigid outer membrane of the elementary body [22].
• This allows purification of the chlamydial major outer membrane protein at high yield in very gentle conditions by using its differential solubility in Sarkosyl and octylglucoside in the presence of dithiothreitol [22].
• Immunoblotting and affinity chromatography indicated that MBP binds to the 40-kDa glycoprotein (the major outer membrane protein) on the outer surface of the chlamydial elementary body [23].
• An unexpected finding was the apparent binding of anti-C3 antibody to a 40-kDa protein of the chlamydial outer membrane complex, perhaps indicating C3 mimicry on the part of the chlamydial major outer membrane protein [24].

Other interactions of ompA

• The major outer membrane protein may be the major route through which ATP accesses ATPase [25].

Analytical, diagnostic and therapeutic context of ompA

• In this study we aimed to characterize the ompA gene by sequencing DNA from all detected cases of Chlamydia trachomatis infection in a Swedish county during 2001, in order to improve the efficiency of contact tracing [26].
• In purified DNA, specific pmp primers (named CpsiA and CpsiB) allowed at least a 10-fold increase of the PCR sensitivity compared to the specific ompA primers for C. abortus, but also for C. psittaci and C. caviae strains [27].
• Analysis of persistently infected cells by immunofluorescent microscopy and immunoblotting with specific antibodies revealed that the atypical chlamydial forms had near-normal levels of the 60-kDa heat shock protein, an immunopathologic antigen, and a paucity of the major outer membrane protein, a protective antigen [28].
• Epitope mapping with solid-phase peptides: identification of type-, subspecies-, species- and genus-reactive antibody binding domains on the major outer membrane protein of Chlamydia trachomatis [29].
• Vaccination with the Chlamydia trachomatis major outer membrane protein can elicit an immune response as protective as that resulting from inoculation with live bacteria [30].

References