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An immunogenic epitope of Chlamydia pneumoniae from a random phage display peptide library is reactive with both monoclonal antibody and patients sera

Naidu BR, Ngeow YF, Wang LF, Chan L, Yao ZJ, Pang T

Immunol Lett, 1998 Jun;62(2):111-5.
PMID: 9698107

Random 15-mer peptides displayed on filamentous phages were screened in binding studies using a Chlamydia pneumoniae-specific monoclonal antibody (RR-402) and affinity-purified, polyclonal sera from patients seropositive for C. pneumoniae infections by the microimmunofluorescence (MIF) test. One 15-mer epitope, epitope Cpnl5A (LASLCNPKPSDAPVT) was identified in both the monoclonal and polyclonal screenings, and showed higher ELISA reactivity with C. pneumoniae MIF-positive sera compared to patients with other chlamydial infections, non-chlamydial respiratory infections and normal healthy sera (MIF-negative). Interestingly, epitope Cpnl5A also showed significant (52%) amino acid sequence homology to the 56 kDa type-specific antigen of Rickettsia tsutsugamushi, a protein implicated in the virulence of this organism.

Matched MeSH terms: Chlamydia Infections/immunology*
Limitations of serodiagnosis in chlamydial genital tract infections

Ngeow YF

Ann Acad Med Singap, 1996 Mar;25(2):300-4.
PMID: 8799029

Infection with Chlamydia trachomatis results in the formation of a variety of antibodies with group, species, subspecies and serovarspecificity. Sera from patients with genital tract infections often show broad reactivity in serological tests. This may be due to the presence of cross-reacting antibodies, repeated infections by different serotypes or concurrent genital and respiratory infections by different chlamydial species. Other factors contributing to difficulties in interpretation include how antibody titres in acute mucosal infections, the occurrence of latent infections and reactivations, and the persistence of IgG which does not allow the differentiation of past from current infections. For these reasons, serology alone is inadequate for the diagnosis of uncomplicated lower genital tract infections. In upper genital tract infections, however, because of difficulties with sampling from the infected site, a positive serology may be the only indications of chlamydial involvement. This paper discusses the principles of chlamydial antibody assays, difficulties with their interpretation and their role in the diagnosis of upper and lower genital tract infections.

Matched MeSH terms: Chlamydia Infections/immunology
Fulltext Chlamydia pneumoniae respiratory infection in a child--a case report

Lum L, Ngeow YF

Med J Malaysia, 1992 Dec;47(4):309-10.
PMID: 1303485

A case of respiratory infection in a child due to Chlamydia pneumoniae is reported. The diagnosis was made by the detection of chlamydial antigen in the tracheal secretion and a significant increase in C. pneumoniae antibody titre. The infection responded well to erythromycin therapy.

Matched MeSH terms: Chlamydia Infections/immunology
Chlamydia pneumoniae IgG seropositivity and clinical history of ischemic heart disease in Singapore

Koh WP, Taylor MB, Chew SK, Phoon MC, Kang KL, Chow VT

J Microbiol Immunol Infect, 2003 Sep;36(3):169-74.
PMID: 14582560

There is still substantial uncertainty concerning the association between Chlamydia pneumoniae and ischemic heart disease. This may partly be explained by the adjustment for potential confounders in different population studies. This is the first study in Singapore to look at the association of C. pneumoniae seropositivity with ischemic heart disease in a multivariate analysis. A random sample of 714 persons aged between 35 and 69 years was selected from the participants of the Singapore National Health Survey conducted in 1998. Data on clinical measurements and conditions were collected using biochemical tests and interviewer-based questionnaires. Ischemic heart disease was defined by the Rose questionnaire and included history suggestive of angina and/or myocardial infarction. Immunoglobulin G antibodies for C. pneumoniae were detected using an indirect microimmunofluorescence test, and seropositivity was defined as IgG titers > or = 1:16. There were no statistically significant differences in the prevalence rates of seropositivity to C. pneumoniae among the three ethnic groups, that is, Chinese (80.4%), Malays (74.0%), and Asian Indians (73.2%). There was no association between seropositivity and ischemic heart disease after adjustment for age alone (OR 1.00, 95% CI 0.54-1.83) or for age, sex, and other risk factors of atherosclerosis (OR 0.99, 95% CI 0.53-1.84). C. pneumoniae Immunoglobulin G seropositivity was not associated with an increased risk of ischemic heart disease as defined by the Rose angina questionnaire in Singapore.

Matched MeSH terms: Chlamydia Infections/immunology*
Prevalence of chlamydial antibody in Malaysians

Ngeow YF, Rachagan SP, Ramachandran S

J Clin Pathol, 1990 May;43(5):400-2.
PMID: 2196283

A single antigen indirect immunofluorescence test was used to screen for chlamydial antibody among Malaysian infants, children, sexually active adults and prostitutes. Of 794 serum samples tested, 361 (45.5%) were positive. Seropositivity increased with age and sexual activity and ranged from 10 to 16% among children under 10 years old to 94.4% among prostitutes. Pregnant women and female adolescents showed a higher antibody prevalence than nonpregnant and older women. Six (13%) infants under 6 months of age were positive for chlamydial IgM.

Matched MeSH terms: Chlamydia Infections/immunology
CPAF, HSP60 and MOMP antigens elicit pro-inflammatory cytokines production in the peripheral blood mononuclear cells from genital Chlamydia trachomatis-infected patients

Cheong HC, Lee CYQ, Cheok YY, Shankar EM, Sabet NS, Tan GMY, et al.

Immunobiology, 2019 01;224(1):34-41.
PMID: 30477893 DOI: 10.1016/j.imbio.2018.10.010

BACKGROUND: Persistent inflammation caused by Chlamydia trachomatis in the female genital compartment represents one of the major causes of pelvic inflammatory disease (PID), ectopic pregnancy and infertility in females. Here, we examined the pro-inflammatory cytokine response following stimulation with three different types of C. trachomatis antigens, viz. chlamydial protease-like factor (CPAF), heat shock protein 60 (HSP60) and major outer membrane protein (MOMP).
METHODS: A total of 19 patients with genital C. trachomatis infection and 10 age-matched healthy controls were recruited for the study. Peripheral blood mononuclear cells (PBMCs) isolated from genital C. trachomatis-infected females were cultured in the presence of CPAF, HSP60 and MOMP antigens, and cytokines were measured by ELISA assay.
RESULTS: We reported that pro-inflammatory cytokines (TNF-α, IL-1β and IL-6) were robustly secreted following antigenic exposure. Notably, CPAP and MOMP were more potent in triggering IL-1β, as compared to HSP60. Elevated levels of the proinflammatory cytokines were also noted in the samples infected with plasmid-bearing C. trachomatis as compared to those infected with plasmid-free strains.
CONCLUSIONS: Our study highlights distinct ability of chlamydial antigens in triggering pro-inflammatory response in the host immune cells.

Matched MeSH terms: Chlamydia Infections/immunology*
Fulltext Diversity of endocervical microbiota associated with genital Chlamydia trachomatis infection and infertility among women visiting obstetrics and gynecology clinics in Malaysia

Cheong HC, Yap PSX, Chong CW, Cheok YY, Lee CYQ, Tan GMY, et al.

PLoS One, 2019;14(11):e0224658.
PMID: 31738795 DOI: 10.1371/journal.pone.0224658

The cervical microbiota constitutes an important protective barrier against the invasion of pathogenic microorganisms. A disruption of microbiota within the cervical milieu has been suggested to be a driving factor of sexually transmitted infections. These include Chlamydia trachomatis which frequently causes serious reproductive sequelae such as infertility in women. In this study, we profiled the cervical microbial composition of a population of 70 reproductive-age Malaysian women; among which 40 (57.1%) were diagnosed with genital C. trachomatis infection, and 30 (42.8%) without C. trachomatis infection. Our findings showed a distinct compositional difference between the cervical microbiota of C. trachomatis-infected subjects and subjects without C. trachomatis infection. Specifically, significant elevations of mostly strict and facultative anaerobes such as Streptococcus, Megasphaera, Prevotella, and Veillonella in the cervical microbiota of C. trachomatis-positive women were detected. The results from the current study highlights an interaction of C. trachomatis with the environmental microbiome in the endocervical region.

Matched MeSH terms: Chlamydia Infections/immunology