Mycoplasma fermentans infection induces human necrotic neuronal cell death via IFITM3-mediated amyloid-β (1-42) deposition

Mycoplasma fermentans is a proposed risk factor of several neurological diseases that has been detected in necrotic brain lesions of acquired immunodeficiency syndrome patients, implying brain invasiveness. However, the pathogenic roles of M. fermentans in neuronal cells have not been investigated. In this study, we found that M. fermentans can infect and replicate in human neuronal cells, inducing necrotic cell death. Necrotic neuronal cell death was accompanied by intracellular amyloid-β (1-42) deposition, and targeted depletion of amyloid precursor protein by a short hairpin RNA (shRNA) abolished necrotic neuronal cell death. Differential gene expression analysis by RNA sequencing (RNA-seq) showed that interferon-induced transmembrane protein 3 (IFITM3) was dramatically upregulated by M. fermentans infection, and knockdown of IFITM3 abolished both amyloid-β (1-42) deposition and necrotic cell death. A toll-like receptor 4 antagonist inhibited M. fermentans infection-mediated IFITM3 upregulation. M. fermentans infection also induced necrotic neuronal cell death in the brain organoid. Thus, neuronal cell infection by M. fermentans directly induces necrotic cell death through IFITM3-mediated amyloid-β deposition. Our results suggest that M. fermentans is involved in neurological disease development and progression through necrotic neuronal cell death.

The prevalence of six species of Mycoplasmataceae in an HIV/AIDS population in Jiangsu Province, China

This study employed culture and polymerase chain reaction (PCR) to examine the prevalence of Ureaplasma urealyticum, Mycoplasma hominis, Mycoplasma genitalium, Mycoplasma fermentans, Mycoplasma penetrans and Mycoplasma pirum in 210 HIV/AIDS patients, 455 sexually transmitted infection (STI) clinic attendees and 245 healthy volunteers from first-void urine specimens for men and endocervical swabs for women. U. urealyticum and M. hominis were detected in 107 (51.0%) and 69 (32.9%) patients in the HIV/AIDS group. At least one of the other four organisms was detected in 34 (16.2%) HIV/AIDS patients, 29 (6.4%) STI clinic attendees and six (2.5%) healthy volunteers. This study showed that U. urealyticum, M. hominis and M. fermentans were significantly more prevalent in HIV/AIDS patients, as were other mycoplasmas. Our results suggest a possible role for co-infection.

Poultry mycoplasmas: sophisticated pathogens in simple guise

Mycoplasmas are a genus within the class Mollicutes (trivial name mollicutes), which are the smallest known prokaryotes capable of self-replication. They have a very small genome, and have evolved to this 'minimalist' status by losing non-essential genes, including those involved in cell wall synthesis. The mollicutes exploit their limited genetic material to the maximum and many are successful pathogens in man, animals, birds and plants. Most of those of veterinary importance are in the genus Mycoplasma and include 4 poultry pathogens of economic importance: Mycoplasma gallisepticum, Mycoplasma synoviae, Mycoplasma meleagridis and Mycoplasma iowae. The pathogenetic mechanisms of mycoplasmas are not fully understood, but they are successful pathogens because they can enter the host and multiply, evade the defence mechanisms, cause damage and escape to infect new hosts. M. gallisepticum is one of several motile species and possesses a terminal tip structure that mediates adherence to its target tissues. For some species, including M. gallisepticum, some of the organisms may become intracellular. Some Mycoplasma species, including the pathogenic poultry species, have a remarkable ability to vary their major surface antigens, a mechanism that is thought to help them to persist in their host by evading the immune response. The molecular and cellular events that lead to the development of lesions and clinical disease are still obscure. Some lesions appear to be the result of indirect damage from the host's inflammatory and cellular responses. Despite short survival times in the environment, mycoplasmas are able to transmit successfully to new hosts. In poultry flocks there is both horizontal and vertical transmission, the former being encouraged by intensive husbandry and stress factors. Establishing the pathways of transmission and the possible role of other birds, such as game and wild birds, as intermediate vectors between poultry flocks is now greatly aided by the availability of modern molecular methods for strain typing.

Ureaplasma in lung. 1. Localization by in situ hybridization in a mouse model

Ureaplasma urealyticum is a common inhabitant of mucosal surfaces but is also associated with a higher incidence of pneumonia and bronchopulmonary dysplasia in preterm infants. Culture and polymerase chain reaction demonstrate high isolation rates of ureaplasma in clinical specimens documenting their presence but do not associate the organism directly with the diseased tissue. In this study, lung tissue samples from newborn mice inoculated intranasally with U. urealyticum were used to develop an in situ hybridization (ISH) test for the organism. In situ hybridization allows the localization of gene expression for visualization within the context of tissue morphology. New techniques which use biotinyl-tyramide based signal amplification have been able to greatly enhance the sensitivity of ISH. Using the Dako GenPoint Catalyzed Signal Amplification system to detect a biotinylated DNA probe specific for an internal nucleotide sequence within the urease gene of U. urealyticum, the organism was detected within the infected murine lung tissues. Electron microscopy was used to verify the presence of the organisms in the positive ISH areas. The ISH procedure developed in this study can be used to analyze the presence of ureaplasma in human neonatal lung tissue with the corresponding histopathology.

Ureaplasma in lung. 2. Association with bronchopulmonary dysplasia in premature newborns

Infants with Ureaplasma urealyticum in the lower respiratory tract are at risk for chronic lung disease (CLD) or bronchopulmonary dysplasia (BPD) but causality has been difficult to prove. The goal of this study was to identify ureaplasma in human neonatal lung tissue using the in situ hybridization (ISH) procedure described in Part 1 (Exp. Mol. Pathol., in press) of this report. By correlating their presence with the histopathologic findings, it may be possible to provide further evidence of the pathogenicity of ureaplasmas and their association with BPD. Lung autopsy tissue from seven infants with positive cultures and seven infants with negative cultures for ureaplasma were included in the study. All culture-positive infants were positive for ureaplasma on ISH and all had histopathologic evidence of BPD. Two of the seven infants with negative cultures were positive for ureaplasma with ISH. Of interest, these two infants were also found to have BPD at autopsy. The other five infants with negative cultures were also negative for ureaplasma on ISH and had no evidence of BPD. This study correlates the presence of U. urealyticum by ISH with the finding of BPD on histopathologic evaluation and provides evidence that it has a role in the development of CLD.

Heat shock protein of Mycoplasma salivarium and Mycoplasma orale strains isolated from HIV-seropositive patients

It has been suggested that infection by some mycoplasma species can act as possible cofactors in the acceleration of immunodeficiency in HIV-infected patients. The present study was designed to examine infections by oral mycoplasma species in HIV-seropositive (HIV(+)) patients. Mycoplasma salivarium and Mycoplasma orale were isolated from 59.5% and 16.7% of 42 HIV(+) patients, respectively. Non-M. salivarium and non-M. orale species were isolated from 40.5% of saliva samples from the HIV(+) group and 20.8% of those from 24 HIV-seronegative (HIV(-)) subjects, respectively. Although the production of superantigen by human peripheral lymphocytes in the isolated mycoplasma species from HIV(+) and HIV(-) subjects was evaluated, none of the examined mycoplasma strains, including ATCC strains of M. salivarium, M. orale, Mycoplasma buccae and Mycoplasma penetrans, were found to produce superantigen. Production of heat shock proteins (HSPs) by isolated mycoplasma strains was examined by immunoblotting using monoclonal antibodies against Helicobacter pylori HSP60. It was found that all the strains of M. salivarium, M. orale, and unidentified mycoplasma species isolated from HIV(+) and HIV(-) groups produced heat shock proteins. HSP production by oral mycoplasma may play a role in the immunomodulation of HIV(+) patients.

Fibromyalgia Syndrome, Idiopathic Widespread Persistent Pain or Syndrome of Myalgic Encephalomyelopathy (SME): What Is Its Nature?

CONTEXT

Fibromyalgia is a disorder that is appearing more and more in the clinical practice but is poorly understood.

OBJECTIVE

This paper attempts to look at all available and reliable data on these conditions and will outline current, scientifically sound understanding of these disorders, treatment modalities and future directions for research. It also attempts to analyze the social and cultural implications.

DATA SOURCES/STUDY SELECTION

Various terms used to describe these syndromes are fibromyalgia (FMS), and myalgic encephalomyelitis (ME). PubMed search was performed. Pertinent articles published in past 25 years and The National Academy of Sciences colloquium on Neurobiology of Pain was also reviewed. In addition, news-articles in the lay press as well as the Internet were monitored for material posted by sufferers of these disorders.

DATA EXTRACTION

Studies were reviewed for clinical presentations, history of these disorders, comorbid conditions, etiology, biochemical and microbiologic abnormalities, abnormalities found on neuroimaging and functional neurophysiologic techniques. In addition patient postings on the Internet and articles appearing in lay press were reviewed and social implications are discussed.

DATA SYNTHESIS

Upon analysis of these materials the review was organized based on the quality of data and it's contextual scientific, cultural and political meaning for this disorder. This review appears to be pointing towards an entirely new paradigm in pain disorders; therefore, a hypothesis and future direction of research is repeatedly suggested.

CONCLUSION

This study proposes an entirely new paradigm in these disorders based on scientific and cultural data.

Detection of Mycoplasma fermentans in broncho-alveolar lavage fluid specimens from AIDS patients with lower respiratory tract infection

OBJECTIVE

To investigate the role of Mycoplasma fermentans in lower respiratory tract disease of HIV-positive patients.

METHODS

A polymerase chain reaction (PCR) assay was used to detect M. fermentans in broncho-alveolar lavage (BAL) fluid and peripheral blood mononuclear cells (PBMCs) collected from 78 hospitalized HIV-positive patients with lower respiratory tract disease (the index group). BAL specimens were also assessed from two control groups; 25 HIV-positive patients without respiratory symptoms and 46 patients with a respiratory illness who did not have risk factors for HIV.

RESULTS

Seventy-one (91%) of the 78 patients who comprised the index group had AIDS. Sixty-one patients provided BAL and PBMC specimens; 16 provided a BAL specimen and one only a PBMC specimen; 15 (25%) of the 61 patients had M. fermentans positive BAL fluid, of whom 10 (67%) also had a positive PBMC specimen. In contrast, of the 46 patients who had a negative BAL fluid, only three (6.4%) had a positive PBMC sample (P < 0.00001 Fisher's exact test). Overall, 21 (27%) of 77 patients had M. fermentans positive BAL fluid. Of these positive patients, 16 also had another microorganism in the BAL fluid and for five patients M. fermentans was detected alone. Compared with patients in the index group, none of the 46 BAL fluid specimens from patients at low risk of HIV infection was M. fermentans positive (P < 0.001, chi2 15.13). Two (8%) of the 25 HIV-positive patients without respiratory symptoms had a M. fermentans positive BAL fluid, positivity that was also statistically different from the index group (P = 0.045, chi2 4.01).

CONCLUSIONS

M. fermentans frequently invades the lower respiratory tract of AIDS patients as an opportunist and may cause disease in some.

Detection of Mycoplasma fermentans in healthy students and patients with congenital immunodeficiency

OBJECTIVES

To determine the prevalence of M. fermentans at different anatomical sites in healthy subjects and in patients with congenital immunodeficiency, and to determine whether haematogenous invasion occurs among the latter.

METHODS

A polymerase chain reaction (PCR) assay was used to detect M.fermentans in throat swabs and urine specimens from healthy students, and from patients with congenital immunodeficiency. Peripheral blood mononuclear cells (PBMCs) from the latter group were also tested.

RESULTS

Sixty-two students provided throat swabs, of which 11 (18%) were M. Jermentans-positive; 46 provided urine specimens, of which eight (17%) were positive. Of the 45 students who provided both throat and urine specimens, 12 (27%) had M. fermentans-positive samples; four in the throat and urine, four in the throat only and four in the urine only. Nineteen of the 20 patients with congenital immunodeficiency provided throat swabs, of which one (5%) was M. fermentans-positive; 19 also provided urine specimens, of which three (16%) were positive. All of the immunodeficient patients provided a PBMC sample, but none was positive.

CONCLUSION

M. fermentans occurred frequently at mucosal sites in a healthy population and in subjects with congenital immunodeficiency. However, such a deficiency did not lead to overt haematogenous invasion.

Mycoplasma species in rapid and slow HIV progressors

We determined the relationship between the presence of Mycoplasma fermentans and Mycoplasma penetrans and the rate of progression of HIV-associated disease in a nested case-control study based on a cohort of 159 HIV-infected patients with different rates of disease progression. Study participants were divided into 3 progression groups: non-progressors who had been HIV-1 seropositive for at least 9 years and had remained asymptomatic with a CD4 cell count of > 500/mm3; slow progressors who had been HIV-1 seropositive for at least 9 years and whose CD4 cell count had fallen below 500 cells, and who had developed symptomatic disease or AIDS; and rapid progressors who had developed AIDS within 5 years of HIV infection. Peripheral blood mononuclear cells (PBMCs) were collected at enrollment and examined by mycoplasma polymerase chain reaction (PCR) assays. Three (7%) of 46 non-progressors, 3 (3%) of 86 slow progressors, and 2 (7%) of 27 rapid progressors were M. fermentans positive. The PBMCs from 91 subjects were tested for M. penetrans DNA and none was positive. The small proportion of M. fermentans-positive patients indicates that the mycoplasma cannot be important in the development of AIDS in the large majority of patients. Furthermore, no association was found between its presence and more rapid HIV disease progression.

Mycoplasma penetrans and other mycoplasmas in urine of human immunodeficiency virus-positive children

Urine samples from children with human immunodeficiency virus (HIV) infection and healthy controls were examined for mycoplasmas by culture. Standard biochemical assays, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and PCR (16S and 16S-23S spacer rRNA region) were used for identification of isolates. Mycoplasmas were identified from 13 (87%) of 15 HIV-positive patients and 3 (20%) of 15 HIV-negative control patients. The frequency and type of mycoplasma varied with the severity of HIV infection. Mycoplasma penetrans, Mycoplasma pirum, Mycoplasma fermentans, and Mycoplasma genitalium were isolated from patients with severe immunodeficiency. Mycoplasma hominis and Ureaplasma urealyticum were isolated more frequently from children in the early stages of HIV infection and from HIV-negative patients. Mycoplasma penetrans was isolated from one (50%) of two patients in Centers for Disease Control and Prevention (CDC) group B and from five (55.5%) of nine pediatric patients with AIDS (CDC group C). This is the first report that indicates that "AIDS-associated" mycoplasmas are more common in HIV-infected children than in HIV-negative controls.

Detection of Mycoplasma genus and Mycoplasma fermentans by PCR in patients with Chronic Fatigue Syndrome

Mycoplasma fermentans and other Mycoplasma species are colonizers of human mucosal surfaces and may be associated with human immunodeficiency virus infection. While many infectious agents have been described in different percentages of patients with Chronic Fatigue Syndrome (CFS), little is known about the prevalence of mycoplasmas and especially M. fermentans in CFS patients. A polymerase chain reaction (PCR)-based assay was used to detect Mycoplasma genus and M. fermentans genomes in peripheral blood mononuclear cells (PBMC) of CFS patients. Blood was collected from 100 patients with CFS and 50 control subjects. The amplified products of 717 bp of Mycoplasma genus, and 206 bp of M. fermentans were detected in DNA purified from blood samples in 52% and 34% of CFS samples, respectively. In contrast, these genomes were found in only 14% and 8% of healthy control subjects respectively (P < 0.0001). All samples were confirmed by Southern blot with a specific probe based on internal sequences of the expected amplification product. Several samples, which were positive for Mycoplasma genus, were negative for M. fermentans indicating that other Mycoplasma species are involved. A quantitative PCR was developed to determine the number of M. fermentans genome copies present in 1 microg of DNA for controls and CFS patients. Mycoplasma copy numbers ranging from 130 to 880 and from 264 to 2400 were detected in controls and CFS positive subjects, respectively. An enzyme immunoassay was applied for the detection of antibodies against p29 surface lipoprotein of M. fermentans to determine the relationship between M. fermentans genome copy numbers and antibody levels. Individuals with high genome copy numbers exhibited higher IgG and IgM antibodies against M. fermentans specific peptides. Isolation of this organism by culture from clinical specimens is needed in order to demonstrate specificity of signal detected by PCR in this study.

Mycoplasma fermentans DNA is infrequently detected in urine specimens from renal transplant recipients

Mycoplasma fermentans is a likely causative agent of HIV-associated nephropathy. In a pilot study, M. fermentans DNA was detected with polymerase chain reaction (PCR) in urine samples from renal allograft recipients; nine (39.1%) out of 23 renal allograft recipients (most of whom had chronic allograft rejection) and none of the 20 controls, were infected with M. fermentans. A cross-sectional study was conducted to investigate the prevalence of M. fermentans in urine samples from renal allograft recipients. Midstream urine samples were centrifuged at 13,000 x g, purified with QIAamp and tested with PCR using RW004/RW005 and an internal control to screen for the presence of inhibitors. Of the 264 participants recruited, 263 completed the questionnaire (172 men, 92 women); 53 had chronic renal allograft rejection, 106 had chronic renal dysfunction without rejection, 69 had a normal renal allograft for more than 3 months and 35 had a renal allograft for less than 3 months. All urine samples yielded positive results for the internal control. Mycoplasma fermentans DNA was detected once i prospectively collected urine samples. The only individual infected with M. fermentans was also seropositive for HIV-1. This study demonstrates that M. fermentans can be at most sporadically detected in urine from patients living with a renal allograft but is not implicated in chronic rejection of allograft.

Genotypic and phenotypic analysis of Mycoplasma fermentans strains isolated from different host tissues

A correlation was found between the expression of a specific Mycoplasma fermentans surface antigen (Pra, proteinase-resistant antigen) and the site of isolation of the organism from the infected host. Strains which expressed Pra were most frequently associated with cells of bone marrow origin, and strains which lacked expression of Pra were most commonly isolated from the respiratory tract, genital tract, and arthritic joints, i.e., epithelial cell surfaces. Pra was previously shown to be resistant to degradation by proteinases and was hypothesized to play a protective role at the organism surface and perhaps to influence which host tissue site was colonized by the organism. The methods used for this phenotyping scheme required isolation and growth of the mycoplasma in quantities sufficient for immunoblot analysis using monoclonal antibodies. We wanted to determine a more rapid and less cumbersome technique to supplement this method for determining the Pra phenotype directly in clinical specimens. Here we describe PCR studies to investigate the movement of a previously identified M. fermentans insertion sequence (IS)-like element. These data showed a correlation between a specific IS genotype and the Pra+ phenotype. Production of a 160-bp product using a single set of IS-based primers was associated with expression of Pra. The genomic IS location resulting in the 160-bp product was determined by using Southern blot analysis and was found to be a stable insertion site characteristic of genotype I strains. Additional analyses of sequences within and flanking the IS insertion sites revealed another pair of PCR primer sites which resulted in the consistent production of a 450-bp amplicon. The stability of this site was dependent on the absence of the IS-like element between the primer sites. The production of this 450-bp amplicon correlated with the Pra mutant phenotype and was characteristic of genotype II strains. The data showed that the sequence within the IS may be unstable and that reliable genotyping sequences are more easily found in the stable genomic sites which flank the IS element.

Gulf War illnesses: complex medical, scientific and political paradox

Gulf War illnesses are a collection of disorders that for the most part can be diagnosed and treated, if effective programmes exist to assist veterans, and in some cases their immediate family members. Although these illnesses are complex and have multi-organ signs and symptoms, a proportion of these patients can be identified as having Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME) and/or Fibromyalgia Syndrome (FMS). Although there are many possible causes of CSF/ME/FMS, chronic infections can explain, at least in a subset of patients, the apparent transmission of these illnesses to family members and the appearance of chronic, multi-organ and auto-immune signs and symptoms. Unfortunately, many veterans who have been diagnosed with chronic infections, such as mycoplasmal infections, cannot obtain adequate treatment for their condition, resulting in their reliance on private physicians and clinics for assistance. This lack of response may ultimately be responsible for the transmission of the illness to non-veterans.

Localized frameshift mutation generates selective, high-frequency phase variation of a surface lipoprotein encoded by a mycoplasma ABC transporter operon

The wall-less mycoplasmas have revealed unusual microbial strategies for adaptive variation of antigenic membrane proteins exposed during their surface colonization of host cells. In particular, high-frequency mutations affecting the expression of selected surface lipoproteins have been increasingly documented for this group of organisms. A novel manifestation of mutational phase variation is shown here to occur in Mycoplasma fermentans, a chronic human infectious agent and possible AIDS-associated pathogen. A putative ABC type transport operon encoding four gene products is identified. The 3' distal gene encoding P78, a known surface-exposed antigen and the proposed substrate-binding lipoprotein of the transporter, is subject to localized hypermutation in a short homopolymeric tract of adenine residues located in the N-terminal coding region of the mature product. High-frequency, reversible insertion/deletion frameshift mutations lead to selective phase variation in P78 expression, whereas the putative nucleotide-binding protein, P63, encoded by the most 5' gene of the operon, is continually expressed. Mutation-based phase variation in specific surface-exposed microbial transporter components may provide an adaptive advantage for immune evasion, while continued expression of other elements of the same transporter may preserve essential metabolic functions and confer alternative substrate specificity. These features could be critical in mycoplasmas, where limitations in both transcriptional regulators and transport systems may prevail. This study also documents that P63 contains an uncharacteristic hydrophobic sequence between predicted nucleotide binding motifs and displays an amphiphilic character in detergent fractionation. Both features are consistent with an evolutionary adaptation favoring integral association of this putative energy-transducing component with the single mycoplasma membrane.

Detection of Mycoplasma fermentans in human saliva with a polymerase chain reaction-based assay

Mycoplasma fermentans and other mycoplasma species may be associated with human immunodeficiency virus infection. Little is known about the ecology of this micro-organism and its natural habitat. A polymerase chain reaction (PCR)-based assay was used to detect M. fermentans in whole saliva. The hypothesis was tested that M. fermentans is present on the mucosal surfaces of the mouth and oropharynx. Whole saliva was collected from 110 adults. The 206-bp amplification product of DNA purified from these samples was detected in ethidium bromide-stained 6% polyacrylamide gels in 49 (44%) samples tested. All samples were confirmed by Southern blotting with a probe based on an internal sequence of the expected amplification product. The data suggest that this organism is often found in saliva and on oropharyngeal mucosal surfaces. Saliva may play a part in its transmission between individuals. Saliva sampling may be helpful in further studies of the ecology and distribution of the micro-organism in human populations.

Gene expression and production of tumor necrosis factor alpha, interleukin 1, interleukin 6, and gamma interferon in C3H/HeN and C57BL/6N mice in acute Mycoplasma pulmonis disease

Studies were conducted to determine whether the production of various cytokines is associated with Mycoplasma pulmonis disease expression. Susceptible C3H/HeN and resistant C57BL/6N mice were inoculated intranasally with 10(7) CFU of virulent M. pulmonis UAB CT or avirulent M. pulmonis UAB T. Expression of genes for tumor necrosis factor alpha (TNF-alpha), interleukin 1 alpha (IL-1 alpha), IL-1 beta, IL-6, and gamma interferon (IFN-gamma) in whole lung tissue and TNF-alpha gene expression in bronchoalveolar lavage (BAL) cells was determined by reverse transcription-PCR using specific cytokine primers at various times postinoculation. In addition, concentrations of TNF-alpha, IL-1, IL-6, and IFN-gamma were determined in BAL fluid and serum samples at various times postinoculation. Our results showed that there was a sequential appearance of cytokines in the lungs of infected mice: TNF-alpha, produced primarily by BAL cells, appeared first, followed by IL-1 and IL-6, which were followed by IFN-gamma. Susceptible C3H/HeN mice had higher and more persistent concentrations of TNF-alpha and IL-6 in BAL fluid than did resistant C57BL/6N mice, indicating that TNF-alpha and possibly IL-6 are important factors in pathogenesis of acute M. pulmonis disease in mice. Serum concentrations of IL-6 were elevated in C3H/HeN mice, but not C57BL/6N mice, following infection with M. pulmonis, suggesting that IL-6 has both local and systemic effects in M. pulmonis disease.

Mycoplasma fermentans and HIV-associated nephropathy

We describe a patient in whom HIV-associated nephropathy developed in association with the detection of Mycoplasma fermentans. This mycoplasma was found in renal tissue by means of a polymerase chain reaction when nephropathy was first evident, and subsequently in urine, blood and the throat. The evidence presented strengthens the causal association of this micro-organism with HIV-induced nephropathy.

A 48-kilodalton Mycoplasma fermentans membrane protein induces cytokine secretion by human monocytes

Mycoplasma fermentans is one of several Mycoplasma species that have been reported to stimulate tumor necrosis factor (TNF) secretion from monocytes. This activity has been associated primarily with the mycoplasma membrane fraction. In this article, we have characterized a membrane protein that stimulates TNF and interleukin 1 beta secretion. The TNF-releasing activity partitioned into the Triton X-114 detergent phase, suggesting that the molecules is hydrophobic. The secretion of TNF is elevated in the presence of serum, which suggests that a serum component may play a role in the interaction between this mycoplasma protein and monocytes. Treatment of monocytes with monoclonal anti-CD14 antibody had no effect on the levels of TNF-releasing activity. By using the monocyte Western blot (immunoblot) technique, we have determined the molecular mass of the active molecule to be 48 kDa. This molecule appears to be distinct from the recently described family of variable lipoproteins of M. fermentans. Mycoplasma particulate material treated with proteinase K lost all inducing activity, whereas lipoprotein lipase-treated samples retained some level of activity.

Dissent in science: styles of scientific practice and the controversy over the cause of AIDS

In this paper, we use a scientific controversy, and the efforts to legitimize and undermine a theory, to examine the co-production of facts and the rules for verifying facts over time. We discuss these processes in terms of what we call 'styles of scientific practice.' In contrast to the focus of idealist philosophers on theory production and validation as forms of logic or ways of thinking, our styles of practice also include the activities of hands and eyes and the discourses between multiple actors in diverse situations. We discuss aspects of the different styles of practice deployed by opponents in a current controversy surrounding the etiology of AIDS to understand how the same data are interpreted in different ways to support diametrically opposed views. Our study describes and examines rules of confirmation used by supporters of the theory that HIV causes AIDS. For example, we introduce an 'epidemiological' style of practice used by AIDS researchers to synthesize information to understand this disease. Styles of practice stress the historically located collective efforts of scientists, technicians, administrators, institutions, and various 'publics' as they build and sustain ways of knowing. Yet, we also show that the 'history' is also a contested construction, not a given in dusty archives. We describe the different versions of history constructed by various participants in the debate to validate their current constructions and definitions of the disease AIDS. Finally, we discuss the politics behind disease definitions and the consequences of different definitions.

Identification of a putative infC-rpmI-rplT operon flanked by long inverted repeats in Mycoplasma fermentans (incognitus strain)

A specific 1542-bp DNA fragment was amplified from Mycoplasma fermentans (incognitus strain) using a unique 23-nucleotide (nt) synthetic deoxyribonucleotide (oligo) (5'-TCCAAAAAGTCCGGAATTTGGGG) as the primer pair in the polymerase chain reaction (PCR). The 23-nt sequence is part of the 29-bp terminal inverted repeat (IR) which forms the left potential stem-and-loop (s&l) structure of the previously identified M. fermentans insertion-sequence(IS)-like genetic element [Hu et al., Gene 93 (1990) 67-72]. The amplified DNA was cloned and sequenced. A pair of 27-bp IR containing the 23-nt synthetic oligo was identified at both termini. Between the IR, there are four potential open reading frames (ORFs) which are arranged adjacent to each other in the order, ORF-1, ORF-2, ORF-3 and ORF-4, with parts of ORF-1 and ORF-2 overlapping. The deduced amino acid (aa) sequences of ORF-2, ORF-3 and ORF-4 are 34 to 60% identical to the translation initiation factor IF3 (encoded by the infC gene), ribosomal proteins L35 (rpmI gene) and L20 (rplT gene) of Escherichia coli and Bacillus stearothermophilus, respectively. In bacteria, the infC-rpmI-rplT genes are organized to function as an operon. There are multiple sites with promoter-like sequences identified upstream from the putative infC gene in the mycoplasma closely resembling the gene arrangement in the bacterial operon. All three genes of ORF-2, ORF-3 and ORF-4 are preceded individually by a strong appropriately spaced (7 and 10 bp) putative Shine-Dalgarno sequence (5'-AAGGA).(ABSTRACT TRUNCATED AT 250 WORDS)

Acquired immunodeficiency syndrome-like illness associated with systemic Mycoplasma fermentans infection in a human immunodeficiency virus-negative homosexual man

A 35-year-old homosexual man developed a composite nodal Kaposi's sarcoma and peripheral T-cell lymphoma that were associated with a peripheral blood CD4-positive lymphocyte count of only 43/mm3. The patient subsequently developed Pneumocystis carinii pneumonitis and eventually died due to disseminated Cryptococcus neoformans. Numerous premortem tests for the presence of human immunodeficiency virus (HIV) types 1 and 2 were negative by the enzyme-linked immunosorbent assay, Western blot, viral isolation, and polymerase chain reaction techniques. Postmortem evaluations for HIV-1, HIV-2, human T-cell lymphotropic virus (HTLV)-I, and HTLV-II also were negative by polymerase chain reaction, immunofluorescence assays, and viral isolation. A systemic infection by Mycoplasma fermentans, however, was documented by immunohistochemistry and polymerase chain reaction in premortem and postmortem tissues. This recently recognized human pathogen has produced systemic infections in patients with the acquired immunodeficiency syndrome (AIDS) and in previously healthy non-AIDS patients who characteristically have a fulminant flu-like illness. Additionally, M fermentans has enhanced the cytopathic effect of HIV in in vitro studies and has produced fatal wasting illnesses with terminal lymphopenia in inoculated adult silvered leaf monkeys. This report is the first description of an association between M fermentans infection and an AIDS-like illness in an HIV-negative individual. The etiology of the severe immunosuppression in this patient and the associated role of M fermentans remain to be determined by further investigations.

Enhanced secretion of immune-modulating cytokines by human lung fibroblasts during in vitro infection with Mycoplasma fermentans

Fibroblasts may play an important role in the modulation of immune and inflammatory responses through elaboration of cytokines. To test this hypothesis, human lung fibroblasts were isolated from transbronchial biopsy specimens and assayed for production of interleukin-6 (IL-6) and granulocyte/macrophage colony-stimulating factor (GM-CSF). The sources of fibroblasts included lung allografts, recipient lungs obtained at time of transplant, and normal lung tissue removed during tumor resection. During the course of these studies, several early-passage fibroblasts from transplant recipients were observed to contain mycoplasma (MP)-like organisms as detected by extranuclear fluorescent staining with Hoechst 33258. Positive staining cultures were associated with isolation of Mycoplasma fermentans. IL-6 and GM-GSF as measured by ELISA were found to be elevated over 50-fold in conditioned medium from MP-infected fibroblasts as compared with noninfected lines. Treatment of cells with mycoplasma removal agent (MRA) eliminated extranuclear Hoechst fluorescence and significantly reduced the production of these cytokines. Tumor necrosis factor-beta (TNF-beta) induction of IL-6 and GM-CSF was amplified synergistically in infected cultures. No additional production of IL-6 or GM-CSF was observed in infected cultures treated with interferon-gamma (IFN-gamma) despite the ability of IFN-gamma to modestly induce IL-6 in uninfected cultures. Thus, in vitro infection of lung fibroblasts with MP represents a potent stimulus for the production of inflammatory cytokines and, therefore, necessitates rigorous control for these organisms in cell culture studies.(ABSTRACT TRUNCATED AT 250 WORDS)

Looking for a 'superantigen' in AIDS: a possible role for Mycoplasma?

The extensive effort made to comprehend the complex immunopathology of human immunodeficiency virus (HIV) infection has resulted in research groups focusing attention on hypotheses as disparate as the possible 'superantigen' potential of HIV and the possible requirement for a Mycoplasma 'cofactor'. Utilizing the recent observation that a Mycoplasma species possesses 'superantigen' properties, this paper attempts to reconcile these seemingly discrepant observations in a model of the acquired immunodeficiency syndrome (AIDS) which builds on the potential contribution of a 'superantigen cofactor' to the ongoing process of HIV infection. A possible role for mycoplasma-induced T-cell proliferation, T-cell dysfunction, B-cell proliferation, and hyperglobulinaemia in the exacerbation of HIV infection is discussed. The relevance of a recent observation regarding protein sequence homology between the mycoplasma adhesion protein and several human class II major histocompatibility complex (MHC) proteins is also examined and incorporated into this model.

High frequency of antibodies to Mycoplasma penetrans in HIV-infected patients

Mycoplasma penetrans, a novel mycoplasma isolated from HIV-1-infected patients with AIDS, has pathogenic properties associated with in-vivo virulence. Enzyme-linked immunosorbent assay and western blotting detected a more than 100 times higher frequency of antibodies to the mycoplasma in serum from HIV-1-infected patients with AIDS (40%) than from HIV-negative controls (0.3%). Serum from 20% of HIV-1-infected, symptom-free individuals also had M penetrans specific antibodies. The antibodies' major immunoreactivity was directed against P35 and P38, the two main lipid-associated membrane protein antigens of the organism. Patients attending sexually transmitted disease clinics had a low frequency of antibody (0.9%). None of 178 HIV-negative patients with different non-AIDS diseases, many associated with immune dysfunction and/or low white cell counts, tested positive for the antibodies. M penetrans, apparently not a commensal and not a simple opportunist, is uniquely associated with HIV-1 infection and AIDS.

Ultrastructural pathology of human immunodeficiency virus infection

The electron microscope has been used with great skill in many aspects of the acquired immunodeficiency syndrome. It has played a critical role in classifying the human immunodeficiency virus, in characterizing the morphogenesis and gene products of the virus, and in elucidating the host cell targets and interactions. With the aid of the electron microscope, new opportunistic pathogens are being identified, and particularly difficult diagnoses are being made. Extrapolations from observations made at the ultrastructural level to the light microscopic level have provided criteria for the diagnosis of several infectious agents. As with any powerful scientific tool, observations must be interpreted with great care by scientists experienced in electron microscopy.

Antigenic diversity thresholds and the development of AIDS

Longitudinal studies of patients infected with HIV-1 reveal a long and variable incubation period between infection and the development of AIDS. Data from a small number of infected patients show temporal changes in the number of genetically distinct strains of the virus throughout the incubation period, with a slow but steady rise in diversity during the progression to disease. A mathematical model of the dynamic interaction between viral diversity and the human immune system suggests the existence of an antigen diversity threshold, below which the immune system is able to regulate viral population growth but above which the virus population induces the collapse of the CD4+ lymphocyte population. The model suggests that antigenic diversity is the cause, not a consequence, of immunodeficiency disease. The model is compared with available data, and is used to assess how the timing of the application of chemotherapy or immunotherapy influences the rate of progress to disease.

Protein and antigen heterogeneity among strains of Mycoplasma fermentans

The proteins and antigens of three strains of Mycoplasma fermentans were compared with those of a mycoplasma, designated "Mycoplasma incognitus," recently identified in tissues of AIDS patients. Previous studies have shown that "M. incognitus" is most likely not a new species but rather a strain of M. fermentans. In the present study, one- and two-dimensional electrophoretic analysis demonstrated the expected similarity between these mycoplasmas, but it also demonstrated several distinct protein differences. Nine proteins were identified as strain variable by two-dimensional gel electrophoresis. Also, immunoblot analysis using rabbit antiserum against the type strain of M. fermentans (strain PG 18) documented the occurrence of size heterogeneity in at least one and possibly two other antigens.

Enhancement of HIV-1 cytocidal effects in CD4+ lymphocytes by the AIDS-associated mycoplasma

Coinfection with Mycoplasma fermentans (incognitus strain) enhances the ability of human immunodeficiency virus type-1 (HIV-1) to induce cytopathic effects on human T lymphocytes in vitro. Syncytium formation of HIV-infected T cells was essentially eliminated in the presence of M. fermentans (incognitus strain), despite prominent cell death. However, replication and production of HIV-1 particles continued during the coinfection. Furthermore, the supernatant from cultures coinfected with HIV-1 and the mycoplasma contained a factor that inhibited the standard reverse transcriptase enzyme assay. The modification of the biological properties of HIV-1 by coinfection with mycoplasma may be involved in the pathogenesis of acquired immunodeficiency syndrome (AIDS).

Mycoplasma fermentans (incognitus strain) infection in the kidneys of patients with acquired immunodeficiency syndrome and associated nephropathy: a light microscopic, immunohistochemical, and ultrastructural study

We studied renal tissues from 203 patients with acquired immunodeficiency syndrome (AIDS). Of the 203 patients, 20 showed light-microscopic changes characteristic of AIDS-associated nephropathy (AAN). Fifteen of the 20 (group A) were examined by immunohistochemistry using Mycoplasma fermentans (incognitus strain)-specific monoclonal antibodies and electron microscopy. Renal tissues from all 15 AAN patients showed positive staining for the incognitus strain mycoplasmal antigens within glomerular endothelial and epithelial cells, glomerular basement membrane, tubular epithelial cells and casts, and mononuclear interstitial cells. Ultrastructural study of these 15 cases revealed mycoplasma-like structures in various locations including glomerular epithelial and endothelial cells, glomerular basement membrane, tubular epithelial cells and casts, and mononuclear interstitial cells. In a parallel study, renal tissues from 15 patients with AIDS with essentially normal renal histology or mild interstitial mononuclear cell infiltration (group B) were also examined. These tissues showed no evidence of incognitus strain mycoplasmal infection in renal parenchymal cells; however, occasional scattered mononuclear interstitial cells were positive for the antigens of this organism. Renal tissues from five patients dying with non-AIDS diseases (group C) showed no staining for the incognitus strain antigens in any location. Therefore, infection of renal parenchymal cells by M fermentans (incognitus strain) in the kidneys of AIDS patients is apparently associated with AAN.

Identification of an insertion-sequence-like genetic element in the newly recognized human pathogen Mycoplasma incognitus

Cloned 2.2-kb DNA (plasmid psb-2.2) of Mycoplasma incognitus, a pathogen in AIDS and non-AIDS patients [Lo et al., Am. J. Trop. Med. Hyg. 41 (1989) 364-376; 601-616], contains a 1405-bp genetic element closely resembling bacterial insertion sequence (IS) elements. This IS-like element has 29-bp terminal inverted repeats with seven mismatches, is immediately flanked by 3-bp direct repeats, and has typical stem-and-loop structures at or near both the termini. Two potential open reading frames (ORF-1 and ORF-2) encode 143 amino acids (aa) and 103 aa, respectively, in this IS-like element. Part (57 aa) of the deduced aa sequence of ORF-2 has a significant homology (43%) with the putative transposase of Escherichia coli IS3. In this study, a series of synthetic oligodeoxyribonucleotides each containing a specific sequence of a selected segment in psb-2.2, have been used as probes which reveal that the IS-like element occurs more than ten times in the genome of M. incognitus. This potentially transposable element has many characteristic features in common with bacterial IS elements.

Genetic and serologic relatedness between Mycoplasma fermentans strains and a mycoplasma recently identified in tissues of AIDS and non-AIDS patients

A mycoplasma previously identified in the tissues of both AIDS and non-AIDS patients dying of an acute fatal disease was earlier shown to share some biologic and genetic properties with a strain of Mycoplasma fermentans, an organism occurring infrequently in the human lower urogenital tract. More extensive genetic and serologic comparisons using DNA/DNA hybridization, DNA base composition (guanine + cytosine), restriction endonuclease DNA analysis, cellular protein patterns and metabolism inhibition serologic procedures confirm that the organism previously designated as "Mycoplasma incognitus" (Mi) is indeed very closely related to strains of M. fermentans. While the genetic and serologic features observed among the newly isolated mycoplasma and two M. fermentans strains suggest a species relationship, it now seems useful to re-examine the biological activities of other freshly isolated M. fermentans strains from man.