Recombinant C. trachomatis MOMP (strain D/UW-3/CX Serovar D)

The OmpA family of outer membrane proteins is a group of genetically related, heat-modifiable, surface-exposed, porin proteins that are in high-copy number in the outer membrane of mainly Gram-negative bacteria. OmpA proteins are characterized by an N-terminal domain that forms an eight-stranded, anti-parallel beta barrel, which is embedded in the outer membrane. The C-terminal domain is globular and located in the periplasmic space. Escherichia coli OmpA is the best characterized of the proteins. Other well-characterized OmpA-equivalent proteins from pathogenic bacteria include Pseudomonas aeruginosa OprF, Haemophilus influenzae P5, Klebsiella pneumoniae OmpA, and Chlamydia trachomatis major outer membrane protein (MOMP). OmpA from the veterinary pathogens Mannheimia haemolytica, Haemophilus parasuis, Leptospira interrogans, and Pasteurella multocida have been studied to a lesser extent. Among many of the pathogenic bacteria, OmpA proteins have important pathogenic roles including bacterial adhesion, invasion, or intracellular survival as well as evasion of host defenses or stimulators of proinflammatory cytokine production. These pathogenic roles are most commonly associated with central nervous system, respiratory and urogenital diseases. Alternatively, OmpA family proteins can serve as targets of the immune system with immunogenicity related to surface-exposed loops of the molecule. In several cases, OmpA proteins are under evaluation as potential vaccine candidates. (C) 2012 Elsevier B.V. All rights reserved.

In 2000, chlamydial strains OK133 and OK135 were isolated from 2 female patients with cervicitis. These strains were unresponsive to commercially available PCR and LCR test 1,,its for the diagnosis of Chlamydia trachomatis infection, and their phenotypic characteristics were very similar. The OK135 nucleotide sequence in MOMP-VD2 gene closely resembled that of Chlamydophila caviae GPIC. A similar strain was isolated in 2003 from a male patient OKM2 with urethritis, from which the strain SC10-6 was cloned by the plaque purification method. The nucleotide sequence of the entire MOMP gene of SC10-6 was exactly the same as that of OK135. Thus, the strains OK135 and SC10-6, together with OK133, have been called C. caviae-like Chlamydia. We designed primers for nested PCR assay, the product of which showed a single-band 311-bp fragment, to detect C. caviae-like Chlamydia. Of swab specimens obtained from 202 patients from 2003 to 2006 (119 male and 8:3 female patients), 18 specimens (8.9%) from 14 male and 4 female patients were positive, suggesting that C. cavide-like Chlamydia infection is rather common. Thus far, it has not been determined whether C. caviae-like Chlamydia is pathogenic for humans.