Recombinant Chlamydia trachomatis MOMP protein (a.a. 252-354) [His]

Background: The association of Chlamydia pneumoniae with atherosclerosis is controversial. We investigated the presence of C. pneumoniae and other Chlamydia spp. in atheromatous carotid artery tissue. Methods: Forty elective carotid endarterectomy patients were recruited (27 males, mean age 65 and 13 females mean age 68), 4 had bilateral carotid endarterectomies ( n = 44 endarterectomy specimens). Control specimens were taken from macroscopically normal carotid artery adjacent to the atheromatous lesions (internal controls), except in 8 cases where normal carotid arteries from post mortem (external controls) were used. Three case-control pairs ere excluded when the HLA DRB gene failed to amplify from the DNA. Genus specific primers to the major outer membrane protein (MOMP) gene were used in a nested polymerase chain reaction (nPCR) in 41 atheromatous carotid specimens and paired controls. PCR inhibition as monitored by spiking with target C. trachomatis. Atheroma severity was graded histologically. Plasma samples were tested by microimmunofluorescence (MIF) for antibodies to C. pneumoniae, C. trachomatis and C. psittaci and the corresponding white cells were tested for Chlamydia spp. by nPCR. Results: C. pneumoniae was not detected in any carotid specimen. Twenty-five of 38 (66%) plasma specimens were positive for C. pneumoniae IgG, 2/38 (5%) for C. trachomatis IgG and 1/38 (3%) for C. psittaci IgG. Conclusions: We were unable to show an association bet een the presence of Chlamydia spp. and atheroma in carotid arteries in the presence of a high seroprevalence of C. pneumoniae antibodies in Northern Ireland.

The levels of subclass-specific immunoglobulin G (IgG) antibodies to five microbial antigens in normal human sera were measured by enzyme-linked immunosorbent assays (ELISA). The aim was to compare the IgG subclass profiles of specific antibodies to diverse antigens originating from virus, intra-and extracellular bacteria. Serum samples from 162 Danish women were analyzed for IgG1, IgG2, IgG3, and IgG4 antibodies against a peptide of the major outer membrane protein (MOMP) of Chlamydia trachomatis, the native outer membrane proteins of Chlamydia pneumoniae, recombinant membrane proteins of Mycoplasma pneumoniae, recombinant parvovirus B19 capsomers (VP1 and VP2) and C-polysaccharide of Streptococcus pneumoniae (pneumococcus). Antibodies specific for viral and bacterial protein antigens belonged mainly to the subclasses IgG1 and IgG3 while the antibody profile specific for pneumococcal C-polysaccharide was dominated by the subclass IgG2. Antibodies to virus, intra-and extracellular bacteria entering the body via the respiratory tract were found primarily to elicit an IgG1 response. In contrast, antibodies specific for MOMP from C. trachomatis, which infects the urogenital tract, were predominantly IgG3. Our results show that the nature of the antigen and/or the site of colonization or infection have impact on which type of IgG subclass a microorganism elicits.