Cleavage/alteration of interleukin-8 by matrix metalloproteinase-9 in the female lower genital tract.

OBJECTIVE: Interleukin-8 (IL-8, CXCL8) plays important roles in immune responses at mucosal sites including in the lower genital tract. Since several types of bacteria produce proteases that cleave IL-8 and many types of bacteria can be present in lower genital tract microbiota, we assessed genital fluids for IL-8 cleavage/alteration. STUDY DESIGN: Genital fluids collected by lavage from 200 women (23 HIV-seronegative and 177 HIV-seropositive) were tested for IL-8 cleavage/alteration by ELISA. RESULTS: IL-8 cleaving/altering activity was observed in fluids from both HIV-positive (28%) and HIV-negative women (35%). There was no clear relationship between the activity and the types of bacteria present in the lower genital tract as determined by high-throughput sequencing of the 16S rRNA gene. Protease inhibitors specific for matrix metalloproteinases (MMPs) reduced the activity and a multiplex assay that detects both inactive and active MMPs showed the presence of multiple MMPs, including MMP-1, -3, -7, -8, -9, -10 and -12 in genital secretions from many of the women. The IL-8-cleaving/altering activity significantly correlated with active MMP-9 as well as with cleavage of a substrate that is acted on by several active MMPs. CONCLUSIONS: These studies show that multiple MMPs are present in the genital tract of women and strongly suggest that MMP-9 in genital secretions can cleave IL-8 at this mucosal site. These studies suggest that MMP-mediated cleavage of IL-8 can modulate inflammatory responses in the lower genital tract.

Human α-amylase present in lower-genital-tract mucosal fluid processes glycogen to support vaginal colonization by Lactobacillus.

Lactobacillus colonization of the lower female genital tract provides protection from the acquisition of sexually transmitted diseases, including human immunodeficiency virus, and from adverse pregnancy outcomes. While glycogen in vaginal epithelium is thought to support Lactobacillus colonization in vivo, many Lactobacillus isolates cannot utilize glycogen in vitro. This study investigated how glycogen could be utilized by vaginal lactobacilli in the genital tract. Several Lactobacillus isolates were confirmed to not grow in glycogen, but did grow in glycogen-breakdown products, including maltose, maltotriose, maltopentaose, maltodextrins, and glycogen treated with salivary α-amylase. A temperature-dependent glycogen-degrading activity was detected in genital fluids that correlated with levels of α-amylase. Treatment of glycogen with genital fluids resulted in production of maltose, maltotriose, and maltotetraose, the major products of α-amylase digestion. These studies show that human α-amylase is present in the female lower genital tract and elucidates how epithelial glycogen can support Lactobacillus colonization in the genital tract.

Effects of Succinic Acid and Other Microbial Fermentation Products on HIV Expression in Macrophages.

Bacterial vaginosis (BV), a common condition in women, is associated with increased shedding of HIV in the female genital tract. While the Lactobacillus species that comprise a healthy vaginal microbiota produce lactic acid, the bacteria common in BV produce high concentrations of short chain fatty acids (SCFAs) and succinic acid. Macrophages are abundant in the lower genital tract mucosa and are thought to play an important role in HIV infection. In this study, we investigated whether SCFAs and succinic acid impacted HIV expression in monocyte-derived macrophages. Monocytes differentiated with either granulocyte-macrophage colony-stimulating factor (GM-CSF) or macrophage colony-stimulating factor (M-CSF) were infected with either HIVBal or an HIV-luciferase reporter virus and treated with SCFAs, succinic acid, or lactic acid. Butyric acid suppressed HIV expression while succinic acid significantly increased expression in macrophages differentiated with either GM-CSF or M-CSF. Acetic, propionic, and lactic acids had no effect on HIV expression. Only succinic acid resulted in a significant increase in interleukin-8 production by infected macrophages. Our results suggest that succinic acid present in increased concentrations in the genital tract of women with BV plays a pro-inflammatory role and increases HIV expression. This could be one factor contributing to increased virus shedding seen in women with BV.

Lectin-dependent enhancement of Ebola virus infection via soluble and transmembrane C-type lectin receptors.

Mannose-binding lectin (MBL) is a key soluble effector of the innate immune system that recognizes pathogen-specific surface glycans. Surprisingly, low-producing MBL genetic variants that may predispose children and immunocompromised individuals to infectious diseases are more common than would be expected in human populations. Since certain immune defense molecules, such as immunoglobulins, can be exploited by invasive pathogens, we hypothesized that MBL might also enhance infections in some circumstances. Consequently, the low and intermediate MBL levels commonly found in human populations might be the result of balancing selection. Using model infection systems with pseudotyped and authentic glycosylated viruses, we demonstrated that MBL indeed enhances infection of Ebola, Hendra, Nipah and West Nile viruses in low complement conditions. Mechanistic studies with Ebola virus (EBOV) glycoprotein pseudotyped lentiviruses confirmed that MBL binds to N-linked glycan epitopes on viral surfaces in a specific manner via the MBL carbohydrate recognition domain, which is necessary for enhanced infection. MBL mediates lipid-raft-dependent macropinocytosis of EBOV via a pathway that appears to require less actin or early endosomal processing compared with the filovirus canonical endocytic pathway. Using a validated RNA interference screen, we identified C1QBP (gC1qR) as a candidate surface receptor that mediates MBL-dependent enhancement of EBOV infection. We also identified dectin-2 (CLEC6A) as a potentially novel candidate attachment factor for EBOV. Our findings support the concept of an innate immune haplotype that represents critical interactions between MBL and complement component C4 genes and that may modify susceptibility or resistance to certain glycosylated pathogens. Therefore, higher levels of native or exogenous MBL could be deleterious in the setting of relative hypocomplementemia which can occur genetically or because of immunodepletion during active infections. Our findings confirm our hypothesis that the pressure of infectious diseases may have contributed in part to evolutionary selection of MBL mutant haplotypes.

Longitudinal assessment of pigtailed macaque lower genital tract microbiota by pyrosequencing reveals dissimilarity to the genital microbiota of healthy humans.

Vaginal bacterial communities play an important role in human health and have been shown to influence HIV infection. Pigtailed macaques (Macaca nemestrina) are used as an animal model of HIV vaginal infection of women. Since the bacterial microbiota could influence retrovirus infection of pigtailed macaques, the genital microbiota in 10 cycling macaques was determined by pyrosequencing. The microbiota of all macaques was polymicrobial with a median of 13 distinct genera. Strikingly, the genera Sneathia and Fusobacterium, both in the phylum Fusobacteria, accounted for 18.9% and 13.3% of sequences while the next most frequent were Prevotella (5.6%), Porphyromonas (4.1%), Atopobium (3.6%), and Parvimonas (2.6%). Sequences corresponding to Lactobacillus comprised only 2.2% of sequences on average and were essentially all L. amylovorus. Longitudinal sampling of the 10 macaques over an 8-week period, which spanned at least one full ovulatory cycle, showed a generally stable presence of the major types of bacteria with some exceptions. These studies show that the microbiota of the pigtailed macaques is substantially dissimilar to that found in most healthy humans, where the genital microbiota is usually dominated by Lactobacillus sp. The polymicrobial makeup of the macaque bacterial populations, the paucity of lactobacilli, and the specific types of bacteria present suggest that the pigtailed macaque microbiota could influence vaginal retrovirus infection.

HSV type 2 infection increases HIV DNA detection in vaginal tissue of mice expressing human CD4 and CCR5.

The goal of this study was to develop an in vivo murine model that can be used to study the influence of HSV-2 on HIV infection. Mice expressing transgenes for human CD4, CCR5, and Cyclin T1 were infected intravaginally with HSV-2 and 3-7 days later infected with HIV. HIV DNA was detected by real-time PCR. The frequency of detection of HIV DNA was significantly higher (65%) in vaginal tissue of HSV-2-infected mice compared to mock-infected mice (35%) when HIV was given 3 days after HSV-2. HSV-2-infected mice also had significantly higher levels of HIV DNA in vaginal tissue. HIV DNA was not detected in vaginal tissue of mice lacking human CD4. Longer periods (5 or 7 days) between infection with HSV-2 and HIV did not increase the frequency of detection or the amount of HIV DNA detected. HIV DNA was also detected in lymph nodes from some of the mice that were infected intravaginally with HSV-2 and HIV. Flow cytometric and mRNA analysis of human CD4 in vaginal tissue suggested that HSV-2 infection increased the number of T cells expressing human CD4 in vaginal tissue. This study provides evidence that HIV infection of cells occurs in the vagina of mice expressing human CD4, CCR5, and Cyclin T1 and that HSV-2 infection increases HIV infection. These findings demonstrate that this model can be used to study the mechanisms responsible for increased susceptibility to HIV in HSV-2-infected persons and for testing preventative treatments.

Effect of mucosal fluid from women with bacterial vaginosis on HIV trans-infection mediated by dendritic cells.

Women with bacterial vaginosis (BV) have a higher risk of HIV transmission but the cause of risk is unknown. Dendritic cells (DC) are implicated in transmission of HIV and we previously observed that DC mature when exposed to mucosal fluid from women with BV. We hypothesized that maturation of DC by BV mucosal fluid would enhance DC-mediated trans-infection of HIV. Monocyte-derived DC (MDDC) were treated with mucosal fluid, incubated with HIV(Bal), and HIV trans-infection was evaluated. While LPS-treated MDDC increased HIV(Bal)trans-infection, BV fluid reduced trans-infection. HIV(Bal) DNA levels in MDDC were not affected by BV fluid or LPS but productive infection of MDDC was decreased by LPS and BV fluid. Mucosal fluid from women with BV does not increase MDDC-mediated trans-infection suggesting that BV does not increase HIV susceptibility by increasing DC-mediated trans-infection. However, indirect effects of DC maturation on HIV transmission cannot be ruled out.

Comparison of the diversity of the vaginal microbiota in HIV-infected and HIV-uninfected women with or without bacterial vaginosis.

BACKGROUND: Whether human immunodeficiency virus (HIV) infection is associated with a change in the diversity of genital microbiota in women was investigated. METHODS: Amplicon length heterogeneity polymerase chain reaction (LH-PCR) analysis and pyrosequencing of the 16S ribosomal RNA gene were used to analyze the diversity of the microbiota in HIV-positive (HIV(+)) and HIV-negative (HIV(-)) women with or without bacterial vaginosis (BV). RESULTS: LH-PCR analysis revealed significantly more microbiota diversity in BV-positive (BV(+)) women than in BV-negative (BV(-)) women, but no significant difference was noted between HIV(+) women and HIV(-) women. Pyrosequencing revealed that Lactobacillus organisms constituted a median of 96% of the bacteria in BV(-) women. BV(+) women had a significantly higher number of taxa found at > or =1% of the total genital microbiota (median, 11 taxa). Common taxa in BV(+) women were Prevotella, Megasphaera, Gardnerella, Coriobacterineae, Lachnospira, and Sneathia. There was a trend (P = .07) toward the presence of a higher number of taxa in HIV(+)BV(+) women than in HIV(-)BV(+) women. Propionibacterineae, Citrobacter, and Anaerococcus were the taxa found only in HIV(+) women (P < .05). CONCLUSIONS: The present study demonstrated that both LH-PCR analysis and pyrosequencing differentiated microbiota in BV(+) women from that in BV(-) women and that pyrosequencing indicated a trend toward increased diversity in BV(+)HIV(+) women, suggesting that HIV infection is associated with changes in the diversity of genital microbiota.

Positive association between HIV RNA and IL-6 in the genital tract of Rwandan women.

Infections and inflammation in the genital tract can influence HIV expression or HIV susceptibility. The goal of this study was to determine if significant relationships exist between cytokines and HIV in genital tract secretions from 57 HIV-seropositive Rwandan women. Genital tract secretions were obtained by cervicovaginal lavage (CVL). Ten different cytokines in CVL were measured by multiplex cytometric bead arrays. HIV RNA in CVL and plasma were measured by quantitative PCR. In univariate analysis, genital tract HIV RNA was significantly associated with plasma HIV RNA and several of the cytokines, while in multivariate analysis, genital tract HIV RNA was significantly associated only with plasma HIV RNA and IL-6. This association of IL-6 with HIV RNA levels suggests that IL-6 is an indicator for conditions that induce HIV expression and that IL-6 may contribute to induction of HIV expression in the genital tract.

Vaginal IL-8 levels are positively associated with Candida albicans and inversely with lactobacilli in HIV-infected women.

IL-8/CXCL8 is induced during infections, but has not been reported for Candida albicans colonization of the female genital tract. Cervicovaginal lavage (CVL) samples were collected from 406 HIV-infected women. IL-8 levels were evaluated by ELISA and compared with levels of C. albicans detected by potassium hydroxide (KOH) and PCR. Levels of lactobacilli, Gardnerella vaginalis and Mycoplasma hominis were also determined by PCR. IL-8 was significantly higher in samples from women with Candida, and regression analysis showed a positive association between IL-8 and Candida. In contrast, there was an inverse relationship between lactobacilli and IL-8. G. vaginalis and M. hominis were not significantly associated with IL-8. This study has shown an association between C. albicans and levels of IL-8 in mucosal genital fluid.

Differential inhibition of human cytomegalovirus (HCMV) by toll-like receptor ligands mediated by interferon-beta in human foreskin fibroblasts and cervical tissue.

Human cytomegalovirus (HCMV) can be acquired sexually and is shed from the genital tract. Cross-sectional studies in women show that changes in genital tract microbial flora affect HCMV infection and/or shedding. Since genital microbial flora may affect HCMV infection or replication by stimulating cells through Toll-like receptors (TLR), we assessed the effects of defined TLR-ligands on HCMV replication in foreskin fibroblasts and ectocervical tissue. Poly I:C (a TLR3-ligand) and lipopolysaccharide (LPS, a TLR4-ligand) inhibited HCMV and induced secretion of IL-8 and Interferon-beta (IFNbeta) in both foreskin fibroblasts and ectocervical tissue. The anti-HCMV effect was reversed by antibody to IFNbeta. CpG (TLR9 ligand) and lipoteichoic acid (LTA, TLR2 ligand) also inhibited HCMV infection in ectocervical tissue and this anti-HCMV effect was also reversed by anti-IFNbeta antibody. In contrast, LTA and CpG did not inhibit HCMV infection in foreskin fibroblasts. This study shows that TLR ligands induce an HCMV-antiviral effect that is mediated by IFNbeta suggesting that changes in genital tract flora may affect HCMV infection or shedding by stimulating TLR. This study also contrasts the utility of two models that can be used for assessing the interaction of microbial flora with HCMV in the genital tract. Clear differences in the response to different TLR ligands suggests the explant model more closely reflects in vivo responses to genital infections.

Bacterial vaginosis and human immunodeficiency virus infection.

Epidemiologic studies indicate that bacterial vaginosis (BV), a common alteration of lower genital tract flora in women, is associated with increased susceptibility to HIV infection. Other recent studies show that HIV is detected more frequently and at higher levels in the lower genital tract of HIV-seropositive women with BV. In vitro studies show that genital tract secretions from women with BV or flora associated with BV induce HIV expression in infected cells. The increased HIV expression appears to be due at least in part to activation through Toll-like receptors (TLR), specifically TLR2. Further research is needed to elucidate how BV contributes to HIV acquisition and transmission.

Utility of Amsel criteria, Nugent score, and quantitative PCR for Gardnerella vaginalis, Mycoplasma hominis, and Lactobacillus spp. for diagnosis of bacterial vaginosis in human immunodeficiency virus-infected women.

Bacterial vaginosis (BV) is a clinical syndrome presenting with a malodorous vaginal discharge and increased vaginal pH. Diagnosis has been based on clinical Amsel criteria and direct Gram stain of vaginal secretions. Human immunodeficiency virus (HIV)-infected participants in the Women's Interagency HIV Study contributed cervicovaginal lavage (CVL) samples. Lactobacilli, Gardnerella vaginalis, and Mycoplasma hominis in cervicovaginal lavage samples were quantified by PCR. Gynecologic evaluation included Nugent score and Amsel criterion assessment. We compared the gold standard Nugent score to Amsel criteria and quantitative bacterial PCR for diagnosing BV in 203 CVL samples from women with Nugent scores of 7 to 10 (BV group) and 203 samples from women with BV Nugent scores of 0 to 3 ("No-BV" group). Only 75 of the 203 CVL samples from women with Nugent scores of 7 to 10 met positive Amsel criteria. Increasing levels of G. vaginalis and M. hominis and decreasing levels of lactobacilli were significantly associated with BV by Nugent score. Of the group with Nugent scores of 7 to 10, 83% and 81% had log(10) G. vaginalis counts and log(10) M. hominis counts greater than 6.81 and 4.82, respectively, while only 30% and 31% of the group with Nugent scores of 0 to 3 were above these thresholds, respectively. There was significant overlap in the log(10) lactobacillus counts between the two groups. Utilizing all three log(10) bacterial counts (G. vaginalis, M. hominis, and lactobacilli) in our model improved the sensitivity and specificity to 83% and 78%, respectively, in comparison with Nugent score. In this cohort, Amsel criteria were poorly predictive of BV. PCR quantification of G. vaginalis and M. hominis from CVL is significantly more sensitive than Amsel criteria for diagnosing BV.

Induction of tumor necrosis factor- alpha secretion and toll-like receptor 2 and 4 mRNA expression by genital mucosal fluids from women with bacterial vaginosis.

BACKGROUND: Bacterial vaginosis (BV) is associated with complications of pregnancy and increased susceptibility to human immunodeficiency virus (HIV) sexual transmission. METHODS: The ability of genital mucosal fluids from women with BV and of microbial flora associated with BV to induce tumor necrosis factor (TNF)- alpha secretion and Toll-like receptor (TLR) 2 and TLR4 mRNA expression was assessed. RESULTS: Primary peripheral-blood mononuclear cells and THP-1 monocytic cells secreted TNF- alpha in response to cervicovaginal lavage (CVL) samples from women with BV. Mycoplasma hominis and Gardnerella vaginalis also stimulated TNF- alpha secretion. Strikingly, CVL samples from women with BV induced up to 60-fold increases in TLR4 mRNA expression, compared with CVL samples from women without BV and with bacteria not associated with BV. Anti-TNF- alpha antibody blocked increases in TLR4 mRNA expression induced by CVL samples from women with BV, indicating that TNF- alpha plays a critical role in induction of TLR4. Both TLR2 and TLR4 mRNA expression were approximately 60-fold higher in cells isolated from the lumen of the genital tract than in cervical mucosal tissue, but lumen TLR mRNA levels did not change significantly after BV treatment. CONCLUSIONS: These experiments show that genital mucosal fluids and certain bacteria from women with BV stimulate TNF- alpha secretion and TLR4 mRNA expression, suggesting mechanisms whereby BV affects pregnancy and HIV transmission.

Relationship of U1 cell HIV-stimulatory activity to bacterial vaginosis and HIV genital tract virus load.

Bacterial vaginosis (BV) has been associated with HIV sexual transmission and increased levels of genital tract HIV RNA. We postulated that BV induces the appearance of substances in the genital tract that stimulate HIV expression locally. To test this, we measured HIV RNA levels in genital mucosal fluid from women with or without BV (defined by Nugent score) and compared them with the ability of those fluids to stimulate HIV expression in the chronically HIV-infected monocytic line U1. The U1 activity was significantly higher in women with BV (median = 1320 pg/ml p24) than in women with normal flora (median = 103 pg/ml p24, p = 0.0001). However, levels of the U1 activity were not significantly associated with levels in the genital tract of HIV RNA. Levels of the U1 activity were also not associated with levels of Gardnerella vaginalis or Mycoplasma hominis in genital fluids, suggesting these bacteria were not the source of the activity. Thus, while these data show a strong association of U1 stimulatory activity with BV, no influence of the U1 activity on genital tract HIV expression was observed.

Female genital-tract HIV load correlates inversely with Lactobacillus species but positively with bacterial vaginosis and Mycoplasma hominis.

BACKGROUND: Bacterial vaginosis (BV) is associated with human immunodeficiency virus (HIV) acquisition. We examined the association between BV and BV-associated bacteria and expression of HIV in the female genital tract. METHODS: HIV RNA, lactobacilli, Gardnerella vaginalis, and Mycoplasma hominis in cervicovaginal lavage (CVL) samples were quantified by polymerase chain reaction (PCR). Gynecologic evaluation included Nugent score assessment, Amsel criteria assessment, detection of other genital-tract infections, and dysplasia grading. CD4 cell count, plasma HIV RNA level, and antiretroviral history were obtained. RESULTS: A total of 203 CVL samples from women with Nugent scores of 7-10 (BV group) and 203 samples from women with Nugent scores of 0-3 (no-BV group) were matched by plasma HIV RNA level and analyzed. After controlling for plasma HIV RNA level and Nugent score in univariate analyses, we found that G. vaginalis and M. hominis bacterial counts, Candida vaginitis, and herpes simplex virus (HSV) were positively associated with CVL HIV RNA levels. In multivariate analysis, only lactobacilli bacterial counts (P=.006; inverse association), M. hominis bacterial counts (P=.0001; positive association), Candida vaginitis (P=.007), and HSV (P=.03) were significantly associated with CVL HIV RNA levels. CONCLUSION: Bacteria associated with BV increase genital-tract HIV RNA levels. Quantitative bacterial counts for lactobacilli and M. hominis are better correlates of CVL HIV RNA than are Nugent score or Amsel criteria. Since plasma virus and CD4 cell levels did not differ between the BV and no-BV groups, these data suggest that the bacterial flora associated with BV influence genital-tract HIV shedding.

Interaction of mannose-binding lectin with HIV type 1 is sufficient for virus opsonization but not neutralization.

Mannose-binding lectin (MBL), a microbe-recognition protein in serum, binds to high mannose glycans on HIV-1 gp120 and has been reported to neutralize the cell line-adapted strain HIV(IIIB). Because HIV primary isolates (PI) are generally more resistant to neutralization by antibodies and considering that PI are produced in primary cells that could alter the number of high mannose glycans on HIV relative to cell lines, we assessed the ability to MBL to neutralize HIV PI. MBL at concentrations up to 50 microg/ml mediated relatively little neutralization (<20%) of HIV PI infection of peripheral blood mononuclear cells (PBMCs). MBL-neutralizing activity was slightly higher for cell line-adapted HIV infection of the H9 T cell line (up to 64% at 50 microg/ml). However, this effect was specific for H9 cells since MBL did not neutralize cell line-adapted virus infection of PBMCs, HIV PI infection of the GHOST cell line, or VSV pseudotyped with HIV gp160 from cell line-derived virus or PI. In contrast to its low activity in neutralization assays, MBL efficiently bound infectious HIV PI and opsonized HIV PI for uptake by monocytic cells. These results show that both PI and cell line-adapted HIV, despite binding of MBL, are relatively resistant to neutralization by levels of MBL normally present in serum. However, binding and opsonization of HIV by MBL may alter virus trafficking and viral-antigen presentation during HIV infection.

Trichomonas vaginalis infection activates cells through toll-like receptor 4.

While Trichomonas vaginalis infection can cause inflammation and influx of leukocytes into the female genital tract, the molecular pathways important in inducing these effects are not known. This study determined if infection with T. vaginalis activates cells through toll-like receptor 4 (TLR4). Genital tract secretions from infected women stimulated TNF-alpha production by cells with functional TLR4 (350 pg/ml) but significantly less by cells that are unresponsive to TLR4 ligands (44 pg/ml, P = 0.001). Secretions collected after clearance of infection also induced significantly lower responses by cells with functional TLR4 (136 pg/ml, P = 0.008). TNF-alpha responses were not reduced by Polymyxin B and did not correlate with beta(2)-defensin levels, indicating that stimulation of cells was not through lipopolysaccharide or beta(2)-defensin. These studies show that T. vaginalis infection results in the appearance in the genital tract of substance(s) that stimulate cells through TLR4, suggesting a mechanism for the inflammation caused by this infection.

Inhibition of DC-SIGN-mediated trans infection of T cells by mannose-binding lectin.

Some dendritic cells (DC) express a cell-surface lectin called 'dendritic cell-specific intracellular adhesion molecule 3 (ICAM-3)-grabbing non-integrin' (DC-SIGN). DC-SIGN has been shown to mediate a type of infection called 'trans' infection, where DC bind human immunodeficiency virus (HIV) and efficiently transfer the virus to T cells. We investigated the possibility that mannose-binding lectin (MBL), a soluble lectin that functions as a recognition molecule in innate immunity and that binds to HIV, could block trans infection mediated by DC-SIGN. Binding studies with glycoprotein (gp)120/gp41-positive and -negative virus preparations suggested that DC-SIGN and MBL bind primarily to glycans on gp120/gp41, as opposed to glycans on host-cell-derived proteins, indicating a close overlap in the binding site of the two lectins and supporting the notion that MBL could prevent binding of HIV to DC-SIGN. Preincubation of X4, R5 or dual-tropic HIV strains with MBL prevented DC-SIGN-mediated trans infection of T cells. The mechanism of MBL blocking trans infection of T cells was at least partly caused by blocking of virus binding to DC-SIGN positive cells. This study shows that MBL prevents DC-SIGN-mediated trans infection of T cells in vitro and suggests that in infected persons, MBL may inhibit DC-SIGN-mediated uptake and spread of HIV.

Detection of bacterial vaginosis-related organisms by real-time PCR for Lactobacilli, Gardnerella vaginalis and Mycoplasma hominis.

The aim of this study was to determine the feasibility of detecting bacterial vaginosis (BV)-related organisms in stored genital tract specimens using real-time PCR. Frozen cervicovaginal lavage (CVL) samples from 21 women were analyzed by real-time PCR for the numbers of Mycoplasma hominis, Gardnerella vaginalis and lactobacilli. Lactobacilli organisms were detected in all CVL samples, G. vaginalis was detected in all but one sample, while M. hominis was detected in only six samples. Using the Amsel criteria to define BV, the samples from women with BV had significantly higher numbers of G. vaginalis organisms than samples from women without BV (P=0.004). In contrast, the number of lactobacilli organisms in BV samples was significantly lower (P=0.013). The number of M. hominis organisms was not significantly different between BV-positive and BV-negative samples. A striking relationship was observed where most of the samples contained high numbers of either lactobacilli or G. vaginalis but not both. These results show that it is possible to determine the presence of BV-related organisms in stored genital tract samples by PCR, suggesting that this could be developed into an objective method that could be useful for certain applications.