Detection of Mycoplasma genitalium-Reactive Cervicovaginal Antibodies among Infected Women

Abstract

Mycoplasma genitalium-reactive cervicovaginal IgA and IgG antibodies were detected in 51.9% and 70.4% of 27 infected women and 22.2% and 18.5% of 27 uninfected controls, respectively. The predominance of MgpBand MgpC-reactive antibodies at the site of infection is consistent with their hypothesized role in selecting antigenic variants during persistent infection.Mycoplasma genitalium is a sexually transmitted pathogen associated with urethritis in men and various inflammatory conditions in women, including cervicitis (reviewed in references 10 and 20). Additionally, M. genitalium is associated with chronic infection, as highlighted by retrospective longitudinal studies of urethritis (7) and cervicitis (3). Such persistence may aggravate the risk of adverse reproductive outcomes, including tubal-factor infertility and preterm birth, conditions associated with this organism (2, 6, 18). Circulating antibodies have been detected in the serum of men with M. genitalium-associated urethritis (19) and women with tubal-factor infertility (2, 18); however, the local antibody response in the lower genital tract remains uncharacterized. To better understand the immunopathogenesis of M. genitalium, we investigated the cervicovaginal antibody response at the initial site of infection.To detect M. genitalium-reactive antibodies in the lower genital tract by immunoblotting, we used cervical and vaginal samples. These specimens were originally collected in our cross-sectional study of M. genitalium infection in women attending a sexually transmitted disease clinic (5). Infection status was determined using an M. genitalium-specific transcription-mediated amplification (TMA) assay (Gen-Probe, San Diego, CA) (22). In the protocol described below, samples from 27 M. genitalium-positive women were tested for reactivity to whole-cell M. genitalium G37 (ATCC 33530) by immunoblotting, with the next consecutive negative study participant serving as a control. All protocols were approved by the University of Washington Institutional Review Board.We prepared G37 lysates from bacteria cultured in H broth (11), harvested by centrifugation, washed in phosphate-buffered saline (PBS), and boiled for 5 min in Novex Tris-glycine SDS sample buffer (Invitrogen, Carlsbad, CA) with 0.2 M dithiothreitol (DTT). The lysate (100 g protein) was separated by electrophoresis using a single-well 7.5% SDS-polyacrylamide gel, and then proteins were transferred to a polyvinylidene difluoride (PVDF) membrane (Invitrogen). Membranes were incubated overnight (4°C) in blocking/diluent buffer (5% nonfat milk in PBS-0.1% Tween 20), cut into 5-mm strips, and reacted for 1 h with a 1:50 dilution of the cervical or vaginal specimen (swabs rehydrated in 2-sucrosephosphate-based transport medium [c2SP]) (22). Membranes were washed (PBS-0.1% Tween 20) and incubated for another hour with peroxidase-conjugated goat anti-human IgG (whole molecule; Sigma-Aldrich, St. Louis, MO), IgA (alpha-chain; Sigma-Aldrich), or IgM (mu-chain; Sigma-Aldrich) diluted 1:10,000 or peroxidase-...

An Epidemiological Study of Mycoplasma genitalium Infections among Males Attending a Sexually Transmitted Disease Clinic in Guangxi, China

“…The univariate logistic regression analyses showed that younger age (Ã35 years), single marital status, or living without a sexual partner were identified as independent risk factors, in accordance with the results of previous epidemiological studies of M. genitalium among other populations (13,17,18). This may be partly explained by the fact that MSPs who were younger, single, or living without a sexual partner were more likely to have active sexual behaviors, lack the acquired immunity of older people (19), receive less surveillance from families or spouses, and have limited economic resources. In addition, a higher education level, previously considered a protective factor against M. genitalium infection (11,13,18), was identified as a risk factor by univariate logistic regression analyses in the current study.…”

Experimental Infection of Pig-Tailed Macaques (Macaca nemestrina) with Mycoplasma genitalium

“…All three animals that produced an M. genitalium-specific immune response demonstrated an increase in reactivity to the antigens MgpB and MgpC (Fig. 3), consistent with the immunodominance of these proteins among humans (6,7,20,21) and our pilot primate A01220 (37). Two animals (A07071 and A07080) developed antibodies to low-molecular-mass proteins coincident with M. genitalium inoculation; the identity of these proteins was not pursued.…”

“…genitalium infection can persist for months to years in infected patients (12)(13)(14)(15)(16)(17)(18)(19), despite the presence of antibodies to M. genitalium in genital exudates of infected women (20) and in the sera of infected men (21). These data suggest that M. genitalium evades the local and systemic immune response, potentially increasing the likelihood of sexual transmission and ascension to the upper reproductive tract.…”

Mycoplasma genitalium Infection Is Associated with Microscopic Signs of Cervical Inflammation in Liquid Cytology Specimens

“…Despite solid evidence for this organism as a cause of male nongonococcal urethritis (NGU), additional studies are needed to unequivocally implicate M. genitalium as a cause of cervicitis and other female re-productive tract syndromes. M. genitalium has a remarkable ability to establish chronic infections of the lower genital tract (13)(14)(15)(16) in lieu of strong antibody responses to at least two outer membrane antigens (17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27). The data regarding M. genitalium as a cause of cervicitis have been conflicting, with approximately half of published studies showing significant associations (28).…”