Mycoplasma fermentans, but not M penetrans, detected by PCR assays in synovium from patients with rheumatoid arthritis and other rheumatic disorders

Substrate flexibility of Mycoplasma fermentans mf1 phosphorylcholine transferase

Zwitterionic modifications of glycans such as phosphorylcholine or phosphoethanolamine occur in a wide range of prokaryotic and eukaryotic organisms and are known for interaction with the mammalian immune system. Unlike the biosynthesis of membrane phospholipids which is well elucidated, very little is known about the transfer of zwitterionic phosphodiester moieties onto glycoconjugates. The presence and function of relevant enzymes has been suggested by gene knockout or mutation and corresponding aberrant phosphorylcholine metabolism. In the current study, the Mycoplasma fermentans phosphorylcholine transferase mf1, with previously confirmed in-vitro activity synthesizing phosphorylcholine-α-glucosyl-1,2-dipalmitoyl glycerol, is demonstrated to not only transfer phosphorylcholine but also phosphoethanolamine from CDP-ethanolamine. Moreover, mf1 is capable of using the β-configuration of the presumed natural substrate but transfers neither to simpler substrates with glucose moieties such as β-D-octyl-glucopyranoside nor to an extended lipid substrate with an additional galactose residue. These findings suggest a certain, but limited, substrate flexibility for bacterial PC-transferases. Mf1 activity is inhibited by β-glycerophosphate, an isomer of part of CDP-glycerol which is known to compete with CDP-ribitol in enzymatic reactions catalyzed by fukutin, a human protein sharing structural homology with mf1. For the first time, a phosphorylcholine transferase, mf1, could be biochemically characterized in vitro and its lipid products with zwitterionic phosphodiesters attached could be detected specifically with the pentraxin serum amyloid P.

Mycoplasmal lipid-associated membrane proteins and Mycoplasma arthritidis mitogen recognition by serum antibodies from patients with rheumatoid arthritis

Mycoplasmal lipid-associated membrane proteins (LAMPs) and Mycoplasma arthritidis mitogen (MAM superantigen) are potent stimulators of the immune system. The objective of this work was to detect antibodies to MAM and LAMPs of Mycoplasma hominis and M. fermentans in the sera of patients affected by rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) to identify mycoplasmal products that can be involved in the etiopathogenesis of these autoimmune diseases. Serum samples from female RA and SLE patients and controls, recombinant MAM, and LAMPs of M. hominis PG21 and M. fermentans PG18 were used in Western blot assays. A similar frequency of sera from patients and controls reactive to MAM was detected. A larger number of M. hominis and M. fermentans LAMPs were recognized by sera from RA patients than controls, but no differences were detected between sera from SLE patients and controls. Among the LAMPs recognized by IgG antibodies from RA patients, proteins of molecular masses in a range of <49 and ≥20 KDa (M. hominis) and <102 and ≥58 KDa (M. fermentans) were the most reactive. These preliminary results demonstrate the strong reactivity of antibodies of RA patients with some M. hominis and M. fermentans LAMPs. These LAMPs could be investigated as mycoplasmal antigens that can take part in the induction or amplification of human autoimmune responses.

Promotion of arthritis and allergy in mice by aminoglycoglycerophospholipid, a membrane antigen specific to Mycoplasma fermentans

Mycoplasmas, which lack a cell wall and are the smallest self-replicating bacteria, have been linked to some chronic diseases, such as AIDS, rheumatoid arthritis (RA), and oncogenic transformation of cells. Their membrane components (lipoproteins and glycolipids) have been identified as possible causative factors in such diseases. Glycoglycerophospholipid (GGPL)-III, a unique phosphocholine-containing aminoglycoglycerophospholipid, is a major specific antigen of Mycoplasma fermentans, and has been detected in 38% of RA patients. Unlike those of lipoproteins, which induce inflammation via Toll-like receptor 2 (TLR2), the pathologic effects of GGPL-III are poorly understood. RA and metal allergies are chronic inflammatory diseases in which autoantigens have been implicated. Here, we examined the effects of chemically synthesized GGPL-III in murine arthritis and allergy models. GGPL-III alone exhibited little inflammatory effect, but promoted both collagen-induced arthritis and nickel (Ni) allergy, although less powerfully than Escherichia coli lipopolysaccharide. The augmenting effect of GGPL-III on Ni allergy was present in mice deficient in either T cells or active TLR4, but it was markedly weaker in mice deficient in macrophages, interleukin-1, or the histamine-forming enzyme histidine decarboxylase than in their control strains. These results suggest that GGPL-III may play roles in some types of chronic diseases via the innate immune system.

Enzymatic synthesis of Mycoplasma fermentans specific glycoglycerophospholipid from 1,2-dipalmitoylglycerol

A gene, mf3, encoding glycosyltransferase in glycoglycerophospholipid (GGPL; GGPL-I and GGPL-III) biosynthesis in Mycoplasma fermentans PG18 was identified by genomic analysis, cloned, modified codon usage, and expressed in Escherichia coli. The mf3 gene consists of an open reading frame of 1221 bp encoding 406 amino acids. The mf3 gene product, Mf3, has 27% amino acid homology with glycosyltransferase of Borrelia burgdorferi but no homology to genes of other Mycoplasma species in the GenBank database. The reaction product of Mf3 using 1,2-dipalmitoilglycerol and UDP-glucose as substrates showed a specific sodium adducted ion at m/z 753, which corresponded to glucopyranosyl dipalmitoilglycerol as determined by MALDI-TOF mass spectrometry. Furthermore, in the reaction product by Mf3 and Mf1 which was a cholinephosphotransferase and previously cloned from M. fermentans PG18, an ion at m/z 896 corresponding to GGPL-I was detected by mass spectrometry. The product ions of choline, phosphocholine, and hexose-bound phosphocholine were detected by tandem MS analysis of protonated molecules at m/z 896. From these results, mf3 was identified as a glycosyltransferase. It was suggested that glucose transfer and phosphocholine transfer to 1,2-dipalmitoylglycerol are involved in the GGPL biosynthesis pathway of M. fermentans PG18.

Biochemical and genetic variation in Mycoplasma fermentans strains from cell line, human and animal sources

AIMS

To investigate the inter-strain variation in (i) substrate utilization and (ii) the restriction fragment length polymorphism (RFLP) pattern based on the distribution of an insertion element (IS1550) in Mycoplasma fermentans strains, and to establish any correlation between subgroups within the species and their source or habitat.

METHODS AND RESULTS

Using a sensitive dynamic pH method, the pattern and kinetics of substrate utilization by a panel of 17 M. fermentans strains from various sources was determined. This study correlated the biochemical characteristics of these strains with RFLP patterns based on the distribution of an insertion sequence (IS1550) with the sources of the strains. The test isolates were divided into four major groups according to the pattern of substrates metabolized. Interestingly, two strains isolated from cell lines in RFLP cluster I failed to utilize arginine. Ovine strains showed distinct substrate utilization patterns and produced RFLP patterns not previously encountered.

CONCLUSIONS

All strains utilized glucose, but the ability to utilize arginine, fructose and N-acetyl glucosamine varied. There was also some correlation evident between the metabolic data and the RFLP clusters.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study has provided a better understanding of the biochemical and genetic diversity of M. fermentans strains from various sources.

Plasmacytoid dendritic cells regulate breach of self-tolerance in autoimmune arthritis

Achieving remission in rheumatoid arthritis (RA) remains elusive despite current biological therapeutics. Consequently, interest has increased in strategies to re-establish immune tolerance to provide long-term disease suppression. Although dendritic cells (DC) are prime candidates in initiating autoreactive T cell responses, and their presence within the synovial environment suggests a role in generation and maintenance of autoreactive, synovial T cell responses, their functional importance remains unclear. We investigated the contribution made by plasmacytoid DCs (pDCs) in the spontaneous breach of tolerance to arthritis-related self proteins, including rheumatoid factor, citrullinated peptide, and type II collagen observed in a novel arthritis model. Selective pDC depletion in vivo enhanced the severity of articular pathology and enhanced T and B cell autoimmune responses against type II collagen. pDC may offer a net anti-inflammatory function in the context of articular breach of tolerance. Such data will be vital in informing DC modulatory/therapeutic approaches.

Molecular cloning and expression of a novel cholinephosphotransferase involved in glycoglycerophospholipid biosynthesis of Mycoplasma fermentans

A gene, mf1, encoding a novel cholinephosphotransferase in glycoglycerophospholipid (GGPL) biosynthesis of Mycoplasma fermentans PG18 was identified by genomic analysis, cloned, and expressed in Escherichia coli. The mf1 gene comprises an open reading frame of 777 bp encoding 258 amino acids. The mf1 gene product, Mf1, has 23% amino acid homology with LicD of Haemophilus influenzae but no homology with genes of other Mycoplasma species in the GenBank database. The reaction product of Mf1 using alpha-glucopyranosyl-1,2-dipalmitoilglycerol and cytidine 5'-diphosphocholine (CDP-choline) as substrates showed the specific protonated molecule at m/z 896, which corresponded to GGPL-I as determined by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS). Furthermore, the product ions of choline, phosphocholine, and hexose-bound phosphocholine were detected by tandem mass spectrometry (MS) analysis of protonated molecules at m/z 896. These results identified mf1 as a novel cholinephosphotransferase and showed that the phosphocholine transfer step is involved in the GGPL biosynthesis pathway of M. fermentans. This is the first report of a GGPL biosynthesis enzyme.

Analysis of bacterial DNA in synovial tissue of Tunisian patients with reactive and undifferentiated arthritis by broad-range PCR, cloning and sequencing

Introduction

Bacteria and/or their antigens have been implicated in the pathogenesis of reactive arthritis (ReA). Several studies have reported the presence of bacterial antigens and nucleic acids of bacteria other than those specified by diagnostic criteria for ReA in joint specimens from patients with ReA and various arthritides. The present study was conducted to detect any bacterial DNA and identify bacterial species that are present in the synovial tissue of Tunisian patients with reactive arthritis and undifferentiated arthritis (UA) using PCR, cloning and sequencing.

Methods

We examined synovial tissue samples from 28 patients: six patients with ReA and nine with UA, and a control group consisting of seven patients with rheumatoid arthritis and six with osteoarthritis (OA). Using broad-range bacterial PCR producing a 1,400-base-pair fragment from the 16S rRNA gene, at least 24 clones were sequenced for each synovial tissue sample. To identify the corresponding bacteria, DNA sequences were compared with sequences from the EMBL (European Molecular Biology Laboratory) database.

Results

Bacterial DNA was detected in 75% of the 28 synovial tissue samples. DNA from 68 various bacterial species were found in ReA and UA samples, whereas DNA from 12 bacteria were detected in control group samples. Most of the bacterial DNAs detected were from skin or intestinal bacteria. DNA from bacteria known to trigger ReA, such as Shigella flexneri and Shigella sonnei, were detected in ReA and UA samples of synovial tissue and not in control samples. DNA from various bacterial species detected in this study have not previously been found in synovial samples.

Conclusion

This study is the first to use broad-range PCR targeting the full 16S rRNA gene for detection of bacterial DNA in synovial tissue. We detected DNA from a wide spectrum of bacterial species, including those known to be involved in ReA and others not previously associated with ReA or related arthritis. The pathogenic significance of some of these intrasynovial bacterial DNAs remains unclear.

An evaluation of PCR methods to detect strains of Mycoplasma fermentans

A panel of 30 putative Mycoplasma fermentans strains, isolated from various sources including human, ovine and cell lines, were tested by a previously described polymerase chain reaction (PCR) to confirm their identity by amplification of a conserved 206 bp region of the insertion sequence IS1550. In addition, the application of another PCR based on the major part of the IS1550 element showed one or two products of different length (1144 and 1341 bp) enabling M. fermentans strains to be divided into two types designated as Type A and Type B. A PCR, which amplifies the macrophage activating lipopeptide gene (malp), supported the identification of all the strains as M. fermentans. Thirteen other species of Mycoplasma from human sources gave negative results in these tests, with the exception of Mycoplasma orale, which was detected by both IS1550-PCRs based on the major part and the conserved 206 bp region of the IS1550 element. This study suggests that all M. fermentans isolates possess both the IS1550 element and the malp gene. In contrast to the IS1550, the malp gene is shown to be species-specific and the use of a malp PCR described here could prove to be a useful adjunct to IS1550 detection as confirmation of the presence of M. fermentans in clinical material.

The importance of B-cells and ecto-5'nucleotidase in Mycoplasma fermentans infection and the relevance to rheumatoid arthritis

The aim of this work was to discover if Mycoplasma fermentans, which is known to infect B cells, could be the cause of the raised ecto-5'-nucleotidase observed in the synovial fluid of rheumatoid arthritis patients. The ecto-5'-nucleotidase activity in the patients' serum has been shown to correlate with the erythrocyte sedimentation rate and DNA from the mycoplasma has been found in the synovial fluid. B lymphoblastoid cell lines were exposed to 16 strains of Mycoplasma fermentans and their ecto-5'-nucleotidase, CD73, was measured both biochemically and by mouse antibodies to human ecto 5'-nucleotidase using the fluorescence activated cell sorter. The type strain, PG 18, did not grow with the B cells. Some of the mycoplasma strains (9/15) increased the cellular ecto-5'-nucleotidase activity from twice to 17 fold, and usually showed 5'-nucleotidase activity themselves. At least one strain, M106, induced human 5'-nucleotidase on the normally 5'-nucleotidase negative Daudi and Raji Burkitt's lymphoma cell lines, and increased sevenfold the 5'-nucleotidase on the monocyte/macrophage cell line THP-1. Growing the cells in aged medium increased the level of mycoplasma infection. This mycoplasma-induced enzyme showed a conformational change and an increase in activity with a glycosylation change involving mannose groups. The other group of strains, mostly of respiratory or cell culture origin, usually did not have any 5'-nucleotidase of their own and decreased the B-cell enzyme activity by about half. Electron microscopy and flow cytometry showed that the strain M106 was filamentous and could be found inside the B-cells. The 5'-nucleotidase-inducing strains of M. fermentans may be important in the aetiology of rheumatoid arthritis.

Evidence for disseminated Mycoplasma fermentans in New Jersey residents with antecedent tick attachment and subsequent musculoskeletal symptoms

Mycoplasma species are one of nature's most abundant groups of microbes. These bacteria inhabit a wide diversity of insect, plant, and animal species, including humans. Certain mycoplasma species have been identified in blood-sucking arthropods, including Ixodes ticks. Frequent human exposure to this genus of ticks led us to explore the possibility of tick-mediated transmission of these bacteria. We evaluated 7 residents of central New Jersey who developed fatigue, musculoskeletal symptoms, and cognitive disturbance after tick attachment. All 7 of these patients lacked both serological evidence and erythema migrans skin lesions characteristic of Lyme disease. We were able to amplify and quantitate Mycoplasma fermentans-specific DNA from their peripheral blood lymphocytes. After antimicrobial therapy, symptoms subsided, and M. fermentans DNA could no longer be detected in their blood specimens. These findings suggest that a subset of disseminated M. fermentans infections may be a vector-mediated process in humans and should be considered in patients with puzzling musculoskeletal presentations.

Rheumatoid arthritis is linked to Proteus--the evidence

Rheumatoid arthritis (RA) is a chronic inflammatory arthritic and potentially disabling condition, mainly affecting women of middle age and having characteristic clinical features. Various microbial agents were implicated in the causation of RA. Extensive literature based on the results of various genetic, microbiological, molecular, and immunological studies carried out by independent research groups supports the role of Proteus mirabilis bacteria in the etiopathogenesis of RA. New diagnostic markers and criteria and the use of a novel therapeutic protocol in the form of antibiotic and dietary measures are suggested to be used together with current treatments in the management of RA. Prospective longitudinal studies with the use of antimicrobial measures in patients with RA are required to establish the therapeutic benefit of this microbe-disease association.

Clinical Applications of the Polymerase Chain Reaction: An Update

The development, in the past decade, of nucleic acid amplification and detection methods is useful in the study of the etiopathogenesis, diagnosis, and management of a variety of clinical (including rheumatologic) disorders. An association between infectious agents and rheumatic disorders has been established through such methods as polymerase chain reaction. This article describes the principles behind polymerase chain reaction-based diagnosis and updates its clinical applications. It is beyond the scope of this article, however, to describe other nucleic acid amplification methods or to include a complete list of all polymerase chain reaction assays that have been developed. Other recent reviews offer additional details.

Mycoplasmas and ureaplasmas as neonatal pathogens

The genital mycoplasmas represent a complex and unique group of microorganisms that have been associated with a wide array of infectious diseases in adults and infants. The lack of conclusive knowledge regarding the pathogenic potential of Mycoplasma and Ureaplasma spp. in many conditions is due to a general unfamiliarity of physicians and microbiology laboratories with their fastidious growth requirements, leading to difficulty in their detection; their high prevalence in healthy persons; the poor design of research studies attempting to base association with disease on the mere presence of the organisms in the lower urogenital tract; the failure to consider multifactorial aspects of diseases; and considering these genital mycoplasmas only as a last resort. The situation is now changing because of a greater appreciation of the genital mycoplasmas as perinatal pathogens and improvements in laboratory detection, particularly with regard to the development of powerful molecular nucleic acid amplification tests. This review summarizes the epidemiology of genital mycoplasmas as causes of neonatal infections and premature birth; evidence linking ureaplasmas with bronchopulmonary dysplasia; recent changes in the taxonomy of the genus Ureaplasma; the neonatal host response to mycoplasma and ureaplasma infections; advances in laboratory detection, including molecular methods; and therapeutic considerations for treatment of systemic diseases.

Relationship between rheumatoid arthritis and Mycoplasma pneumoniae: a case-control study

OBJECTIVE

Rheumatoid arthritis (RA) has a complex and multifactorial aetiology. Infectious agents could start this disease. The majority of the characteristics of this infirmity can be observed in chronic arthritis produced by mycoplasmas in animals. In this study the association between Mycoplasma pneumoniae and RA has been evaluated.

METHODS

A case-control study was performed. Sera taken from 78 RA patients and from 156 controls were analysed to ascertain the levels of immunoglobulin G (IgG) against M. pneumoniae. Other variables, like age, gender, work status, history of pneumonia, etc., were recorded in a questionnaire.

RESULTS

The presence of antibodies against M. pneumoniae was associated with RA (odds ratio=2.34, P<0.001).

CONCLUSIONS

The results suggest that M. pneumoniae could be a cofactor in the pathogenesis of RA; however, more studies need to be done.

The Mycoplasma fermentans prophage φMFV1: genome organization, mobility and variable expression of an encoded surface protein

The approximately 16 kb genome of the Mycoplasma fermentans phiMFV1 prophage is described, and its mobility, replication and effect on the mycoplasma surface phenotype are demonstrated. In various M. fermentans strains, phiMFV1 was either absent or integrated at diverse (and sometimes multiple) chromosomal sites, each marked by a conserved TTTTTA target sequence that is duplicated upon integration. Precise excision, replication of an extrachromosomal form and loss of phiMFV1 from the mycoplasmal genome were documented in a series of clonal derivatives of M. fermentans propagated in culture. Of 18 open reading frames (ORFs) encoded by phiMFV1, most can be ascribed functions related to phage biology, whereas one encodes a unique coiled-coil membrane surface protein, Mem, that was confirmed to be expressed in propagating populations of M. fermentans. With the exception of Mem and other minor ORFs, the striking similarity between the deduced proteomes of phiMFV1 and the recently described phiMAV1 of arthritogenic strains of Mycoplasma arthritidis, along with the prominent gene synteny between these elements, provides the taxonomic basis for a new family of prophage. Their coding features are consistent with long-term residence in mycoplasma genomes and the divergence of species within a phylogenetic clade of mycoplasmas. The unique Mem protein expressed from phiMFV1 and the unique hypothetical surface lipoproteins encoded by phiMAV1 and phiMFV1 also suggest that prophage-associated genes may provide specific, selectable phenotypic traits during co-evolution of mycoplasma species with their respective mammalian hosts. Retention of these labile prophage elements in organisms with such drastically reduced genome sizes implies a significant role in adaptation and survival.

Applications of polymerase chain reaction in rheumatology

Polymerase chain reaction (PCR) is a highly sensitive and specific method for detection and quantification of specific nucleic acids from a clinical sample. With its use, genetic, infectious, neoplastic, and autoimmune diseases can be diagnosed and managed with a high level of sensitivity, accuracy, and rapidity. This technique exactly reproduces unlimited copies of DNA, even if only a small amount are present initially. PCR assays can detect presence of fastidious and slow-growing microorganisms, such as chlamydia, mycoplasmas, mycobacterias, and viruses directly from clinical specimens and also can detect antimicrobial resistance. The value of viral load measurement by nucleic acid amplification in the management of patients with HIV infection or hepatitis C has also been well established. From the point of view of a clinician, the applications of PCR are focused mainly in the amplification and detection of diagnostic DNA segments from the genomes of both pathogens and patients.

A 4.1-kilodalton polypeptide in the cultural supernatant of Mycoplasma fermentans is one of the substances responsible for induction of interleukin-6 production by human gingival fibroblasts

The cultural supernatant of Mycoplasma fermentans induced interleukin-6 production by human gingival fibroblasts. The active entities were divided into hydrophilic and hydrophobic substances. In this study, we purified a 4.1-kilodalton polypeptide from the hydrophilic substances. It reacted with polyclonal antibodies to M. fermentans and activated human macrophages.

High prevalence of Mycoplasma pneumoniae in intestinal mucosal biopsies from patients with inflammatory bowel disease and controls

Intestinal microflora are believed to play an important role in the pathogenesis of inflammatory bowel disease (IBD). Mycoplasma have been suggested previously as organisms of ubiquitous distribution with the potential to cause inflammatory diseases, including IBD in susceptible individuals. The aim of this study was to determine the frequency of the presence of M. pneumoniae DNA in intestinal biopsies from patients with IBD and non-IBD controls using a microplate polymerase chain reaction-hybridization assay (PCR-ELISA). A total of 260 endoscopic biopsies (49 from 19 patients with Crohn's disease, 76 from 27 patients with ulcerative colitis, and 135 from 43 non-IBD controls) were used in this study. Overall, M. pneumoniae-specific DNA was detected in 100 endoscopic biopsy samples (38.5%). Among them, the detection rate of M. pneumoniae DNA was significantly higher in biopsies from patients with CD (59.2%) than in those from patients with UC (26.3%) or non-IBD controls (37.7%) (chi2 = 13.65, P < or = 0.001). The high prevalence of M. pneumoniae in both IBD patients and controls suggest this organism is ubiquitous and may persist in the intestinal mucosa. Epidemiological studies in IBD suggest acquisition of some agents early in life probably during epidemics in temperate latitudes. M. pneumoniae could be one of the ubiquitous agents implicated in the pathogenesis of IBD.

Chromosomal DNA from a variety of bacterial species is present in synovial tissue from patients with various forms of arthritis

OBJECTIVE

We and others have reported the presence of Chlamydia and other bacterial species in joint specimens from patients with reactive arthritis (ReA). The present study was conducted to investigate whether bacteria other than those specified by diagnostic criteria for ReA could be identified in synovial fluid (SF) or tissue from patients with various arthritides, and whether the presence of such organisms corresponds to particular clinical characteristics in any patient set or subset.

METHODS

DNA in synovial biopsy samples and SF obtained from 237 patients with various arthritides, including ReA, rheumatoid arthritis, and undifferentiated oligoarthritis, was assayed by polymerase chain reaction (PCR) using "panbacterial" primers; we chose only samples known to be PCR negative for Chlamydia, Borrelia, and Mycoplasma species. PCR products were cloned, and cloned amplicons from each sample were sequenced; DNA sequences were compared against all others in GenBank for identification of bacterial species involved.

RESULTS

Ten percent of patient samples were PCR positive in panbacterial screening assays. Bacterial species identified belonged to the genera Neisseria, Acinetobacter, Moraxella, Salmonella, Pseudomonas, and others. Thirty-five percent of PCR-positive patients showed the presence of DNA from more than a single bacterial species in synovium; overall, however, we could identify no clear relationship between specific single or multiple bacterial species in the synovium and any general clinical characteristics of any individual or group of patients.

CONCLUSION

This analysis provides the first systematic attempt to relate bacterial nucleic acids in the synovium to clinical characteristics, joint findings, and outcomes. Many patients with arthritis have bacterial DNA in the joint, and, in some cases, DNA from more than a single species is present. However, except for 1 case of a control patient with staphylococcal septic arthritis, it is not clear from the present study whether the synovial presence of such organisms is related to disease pathogenesis or evolution in any or all cases.

Monoclonal antibody against Mycoplasma fermentans-specific aminoglycoglycerolipid

Previously, we reported that Mycoplasma fermentans has specific antigens (phosphocholine-containing glycoglycerolipids: GGPL-I and GGPL-III) and discussed the possibility of their pathogenic role. In this paper, we report the characterization of a monoclonal antibody (MF-III-1) specific to GGPL-III (phosphocholine-containing aminoglycoglycerolipid) using methods of electron microscopy, immunofluorescence cell surface staining, laser scanning microscopy, immunoelectron microscopy, and thin-layer chromatography immunostaining. The MF-III-1 antibody specifically recognized M. fermentans attached to the surface of HTLV-I-infected human helper T-cells, and it did not cross-react with other lipids nor with human T-cell antigens. Since MF-III-1 distinguishes GGPL-III from GGPL-I, the binding site may include a serinol (2-amino-1,3-propanediol) residue of GGPL-III. MF-III-1 is useful for the in vitro study of M. fermentans, and may also be useful as a tool for the study of the involvement of M. fermentans in human diseases.

Reactive arthritis: preliminary microbiologic analysis of the human temporomandibular joint

PURPOSE

The presence of Chlamydia trachomatis has been previously shown in the temporomandibular joint (TMJ). This study investigated whether the presence of other bacteria associated with reactive arthritis (ReA) can be identified in the TMJ.

MATERIALS AND METHODS

Posterior bilaminar tissue removed during TMJ surgery from 26 patients (24 F, 2 M) was evaluated for the presence of C. trachomatis, Mycoplasma fermentans, Mycoplasma genitalium, Campylobacter jejuni, Yersinia enterocolitica, Salmonella spp, and Shigella spp by highly specific polymerase chain reaction (PCR) assays.

RESULTS

Bacterial DNA was identified in the TMJ as follows: C. trachomatis, 11 of 26 (42%); M. fermentans/orale, 6 of 26 (23%); M. genitalium, 9 of 26 (35%). Nine of 26 TMJs (35%) had the presence of a single bacterial species. Eight of 26 TMJs (31%) had more than 1 species, as follows: C. trachomatis with either M. genitalium or M. fermentans/orale in 5 of 26 (19%), M. fermentans/orale with M. genitalium 2 of 26 (8%), and C. trachomatis/M. fermentans/orale/M. genitalium, 1 of 26 (4%). A total of 17 of 26 (65%) of TMJs had the presence of bacteria identified in the TMJ. Campylobacter jejuni, Y. enterocolitica, Salmonella spp, and Shigella spp were not identified in any samples.

CONCLUSIONS

The presence of M. genitalium in the human TMJ has not been previously reported. The presence of bacteria in the TMJ, either singly or concurrently with other bacteria, may serve as the pathogenetic mechanism of TMJ inflammation. The presence of 2 bacteria from the urogenital tract in the TMJ suggests that internal derangement of the TMJ may occur as a result of a sexually acquired infection.

Reverse transcriptase-PCR analysis of bacterial rRNA for detection and characterization of bacterial species in arthritis synovial tissue

Onset of rheumatoid arthritis (RA) is widely believed to be preceded by exposure to some environmental trigger such as bacterial infectious agents. The influence of bacteria on RA disease onset or pathology has to date been controversial, due to inconsistencies between groups in the report of bacterial species isolated from RA disease tissue. Using a modified technique of reverse transcriptase-PCR amplification, we have detected bacterial rRNA in the synovial tissue of late-stage RA and non-RA arthritis controls. This may be suggestive of the presence of live bacteria. Sequencing of cloned complementary rDNA (crDNA) products revealed a number of bacterial sequences in joint tissue from each patient, and from these analyses a comprehensive profile of the organisms present was compiled. This revealed a number of different organisms in each patient, some of which are common to both RA and non-RA controls and are probably opportunistic colonizers of previously diseased tissue and others which are unique species. These latter organisms may be candidates for a specific role in disease pathology and require further investigation to exclude them as causative agents in the complex bacterial millieu. In addition, many of the detected bacterial species have not been identified previously from synovial tissue or fluid from arthritis patients. These may not be easily cultivable, since they were not revealed in previous studies using conventional in vitro bacterial culture methods. In situ hybridization analyses have revealed the joint-associated bacterial rRNA to be both intra- and extracellular. The role of viable bacteria or their nucleic acids as triggers in disease onset or pathology in either RA or non-RA arthritis controls is unclear and requires further investigation.

Identification of Mycoplasma fermentans in synovial fluid samples from arthritis patients with inflammatory disease

Since 1970 Mycoplasma fermentans has been suspected of being associated with rheumatoid arthritis. However, this association has been difficult to prove, and this has been our goal. The distribution of M. fermentans was studied in the synovial fluid of patients suffering from different arthritides. Samples of synovial fluid were taken from patients with well-defined disease and a clear diagnosis. After removal of the inflammatory cells and hyaluran, they were treated with proteinase K and tested by a single or fully nested PCR with primers directed against part of the two 16S rRNA genes of M. fermentans. The product was sequenced automatically, by using an ALF Express automatic sequencer, to confirm the mycoplasma species and to identify the strain since the two genes were usually found to be polymorphic. This was also true of the type strain, strain PG18. M. fermentans was detected in 23 of 26 (88%) rheumatoid arthritis patients, and four different strains were found. It was also found in 7 of 8 (88%) of the nonrheumatoid inflammatory arthritis patient group, which consisted of one patient with reactive arthritis, one patient with pauciarticular juvenile chronic arthritis, two patients with gout, two patients with ankylosing spondylitis, and two patients with psoriatic arthritis, only one of whom was infected with M. fermentans. It was not detected in any of the 10 osteoarthritis patients. M. fermentans was therefore found to be a variable and very common organism in arthritic patients with inflammatory joint exudates and may well prove to be important in the etiology of the diseases.

Effects of Mycoplasma fermentans incognitus on differentiation of THP-1 cells

Mycoplasma fermentans incognitus has been isolated from human tissue in patients both with and without AIDS who died of systemic infection. M. fermentans incognitus and other strains of M. fermentans have been associated with rheumatoid arthritis. While cell extracts of M. fermentans incognitus can induce changes in murine and human cells of the monocytic lineage, little is known about interactions of viable organisms with such cells. Because of the central role of macrophages in chronic inflammation, we examined the effects of M. fermentans incognitus on surface markers and functions of THP-1 cells, a well-characterized human monocytic cell line. This cell line has been used extensively in studies of macrophage differentiation, especially following exposure to phorbol esters. Changes in cell morphology, phagocytosis, rate of cell division, and selected surface markers were evaluated in cultures of THP-1 cells exposed to phorbol myristate acetate (PMA), M. fermentans incognitus, or both. As reported by other investigators, PMA induced THP-1 cells to differentiate into cells resembling tissue macrophages. M. fermentans incognitus only minimally affected changes induced by PMA, slightly increasing the percentage of cells positive for FCgammaRI and major histocompatibility complex (MHC) class II antigens. M. fermentans incognitus alone induced an incomplete arrest in the cell cycle at G0 phase, increased phagocytic ability, and enhanced expression of FCgammaRI, CR3, CR4, and MHC class II antigens.

Involvement of mitogen-activated protein kinase pathways in interleukin-8 production by human monocytes and polymorphonuclear cells stimulated with lipopolysaccharide or Mycoplasma fermentans membrane lipoproteins

Interleukin-8 (IL-8) is a chemokine that belongs to the alpha-chemokine or CXC subfamily and is produced by a wide variety of human cells, including monocytes and polymorphonuclear cells (PMN). IL-8 is secreted in response to inflammatory stimuli, notably bacterial products such as lipopolysaccharide (LPS), but little is known about the mechanisms by which these agents mediate IL-8 induction. In this report, we show that Mycoplasma fermentans lipid-associated membrane proteins (LAMPf) induce the production of high levels of IL-8 by THP-1 (human monocyte) cells and PMN at the same extent as LPS. It was previously demonstrated that stimulation of monocytic cells with either LPS or LAMPf led to a series of common downstream signaling events, including the activation of protein tyrosine kinase and of mitogen-activated protein kinase cascades. By using PD-98059 and SB203580, two potent and selective inhibitors of MEK1 (a kinase upstream of ERK1/2) and p38, respectively, we have demonstrated that both ERK1/2 and p38 cascades play a key role in the production of IL-8 by monocytes and PMN stimulated with bacterial fractions.

Molecular biology and pathogenicity of mycoplasmas

The recent sequencing of the entire genomes of Mycoplasma genitalium and M. pneumoniae has attracted considerable attention to the molecular biology of mycoplasmas, the smallest self-replicating organisms. It appears that we are now much closer to the goal of defining, in molecular terms, the entire machinery of a self-replicating cell. Comparative genomics based on comparison of the genomic makeup of mycoplasmal genomes with those of other bacteria, has opened new ways of looking at the evolutionary history of the mycoplasmas. There is now solid genetic support for the hypothesis that mycoplasmas have evolved as a branch of gram-positive bacteria by a process of reductive evolution. During this process, the mycoplasmas lost considerable portions of their ancestors' chromosomes but retained the genes essential for life. Thus, the mycoplasmal genomes carry a high percentage of conserved genes, greatly facilitating gene annotation. The significant genome compaction that occurred in mycoplasmas was made possible by adopting a parasitic mode of life. The supply of nutrients from their hosts apparently enabled mycoplasmas to lose, during evolution, the genes for many assimilative processes. During their evolution and adaptation to a parasitic mode of life, the mycoplasmas have developed various genetic systems providing a highly plastic set of variable surface proteins to evade the host immune system. The uniqueness of the mycoplasmal systems is manifested by the presence of highly mutable modules combined with an ability to expand the antigenic repertoire by generating structural alternatives, all compressed into limited genomic sequences. In the absence of a cell wall and a periplasmic space, the majority of surface variable antigens in mycoplasmas are lipoproteins. Apart from providing specific antimycoplasmal defense, the host immune system is also involved in the development of pathogenic lesions and exacerbation of mycoplasma induced diseases. Mycoplasmas are able to stimulate as well as suppress lymphocytes in a nonspecific, polyclonal manner, both in vitro and in vivo. As well as to affecting various subsets of lymphocytes, mycoplasmas and mycoplasma-derived cell components modulate the activities of monocytes/macrophages and NK cells and trigger the production of a wide variety of up-regulating and down-regulating cytokines and chemokines. Mycoplasma-mediated secretion of proinflammatory cytokines, such as tumor necrosis factor alpha, interleukin-1 (IL-1), and IL-6, by macrophages and of up-regulating cytokines by mitogenically stimulated lymphocytes plays a major role in mycoplasma-induced immune system modulation and inflammatory responses.

Detection of Mycoplasma salivarium and Mycoplasma fermentans in synovial fluids of temporomandibular joints of patients with disorders in the joints

Thirty-six synovial fluid samples of temporomandibular joints were obtained from 33 patients with pain and anterior disk displacement (closed lock) in the joints. DNAs were prepared from the samples and amplified by a PCR-based assay specific for Mycoplasma salivarium or Mycoplasma fermentans. Of the 36 samples, five (14%), three (8%), and 19 (53%) were positive for M. salivarium, M. fermentans and both, respectively.

Genotypic characterization of seven strains of Mycoplasma fermentans isolated from synovial fluids of patients with arthritis

We performed a genotypic characterization of seven strains of Mycoplasma fermentans which have been isolated from the synovial fluid of patients with rheumatoid arthritis (n = 2), spondyloarthropathy (n = 1), and unclassified arthritis (n = 4). We compared them to three reference strains (strains PG18 and K7 and incognitus strain) and to a clinical isolate from the urethra of a patient with nongonococcal urethritis. The characterization methods included electrophoresis of native DNA, arbitrarily primed PCR, and restriction fragment length polymorphism analysis following conventional and pulsed-field gel electrophoresis. Southern blot analysis with a probe internal to an insertion sequence was performed with the restriction products produced by the last two techniques. No extrachromosomal DNA sequences were detected. The M. fermentans strains identified by these methods did not present a unique profile, but they could be separated into two main categories: four articular isolates were genetically related to PG18 and the three other isolates, the urethral isolate, and the incognitus strain were related to K7. We also looked for the presence of the bacteriophage MAV1 (associated with the arthritogenic property of Mycoplasma arthritidis in rodents) in the M. fermentans strains. MAV1 DNA was not detected in either the clinical isolates or the reference strains of M. fermentans.