Differential Downstream Effects of Cd40 Ligation Mediated by Membrane or Soluble CD40L and Agonistic Ab: A Study on Purified Human B Cells

With the addition of various cytokines, the CD40-CD40 ligand (CD40L) system can act as a T-helper cell surrogate to permit B lymphocytes to produce large amounts of polyclonal Ig. In the present study, we tested six CD40-CD40L stimulation models: (i, ii) soluble agonistic 89 and G28.5 mAbs; (iii, iv) ‘89’ and ‘G28.5’ bound via their Fc fragments on CDw32-transfected mouse fibroblasts; (v) purified, soluble, trimeric human CD40L molecules (sCD40L); and (vi) human CD40L expressed by a CD40L-transfected mouse fibroblastic cell line (LCD40L). Target B cells consisted of purified blood and tonsillar CD19+ lymphocytes cultured in the presence of CD40 stimuli and IL-2 and IL-10, added at the onset of each B cell culture. A) There was differential expression of CD69, CD80 and CD86 exposure to sCD40L and LCD40L was ensued by the strongest % MFI changes over control. B) In blood B cells, mAbs and sCD40L induced IgA, IgM and IgG production almost equally well; LCD40L proved less efficient. In contrast, in tonsil B cells, LCD40L induced significantly more IgA, IgG 1, IgG3and IgM production than other signals. Using certain CD40/CD40L stimuli to model in vitro Ig production, a system used regularly in many laboratories, may affect the interpretation based on the cell type and on the CD40/CD40L system used.

Complexes between nuclear factor-κB p65 and signal transducer and activator of transcription 3 are key actors in inducing activation-induced cytidine deaminase expression and immunoglobulin A production in CD40L plus interleukin-10-treated human blood B cells

The signal transducer and activator of transcription 3 (STAT3) transcription factor pathway plays an important role in many biological phenomena. STAT3 transcription is triggered by cytokine-associated signals. Here, we use isolated human B cells to analyse the role of STAT3 in interleukin (IL)-10 induced terminal B cell differentiation and in immunoglobulin (Ig)A production as a characteristic readout of IL-10 signalling. We identified optimal conditions for inducing in-vitro IgA production by purified blood naive B cells using IL-10 and soluble CD40L. We show that soluble CD40L consistently induces the phosphorylation of nuclear factor (NF)-κB p65 but not of STAT3, while IL-10 induces the phosphorylation of STAT3 but not of NF-κB p65. Interestingly, while soluble CD40L and IL-10 were synergistic in driving the terminal maturation of B cells into IgA-producing plasma cells, they did not co-operate earlier in the pathway with regard to the transcription factors NF-κB p65 or STAT3. Blocking either NF-κB p65 or STAT3 profoundly altered the production of IgA and mRNA for activation-induced cytidine deaminase (AID), an enzyme strictly necessary for Ig heavy chain recombination. Finally, the STAT3 pathway was directly activated by IL-10, while IL-6, the main cytokine otherwise known for activating the STAT3 pathway, did not appear to be involved in IL-10-induced-STAT3 activation. Our results suggest that STAT3 and NF-κB pathways co-operate in IgA production, with soluble CD40L rapidly activating the NF-κB pathway, probably rendering STAT3 probably more reactive to IL-10 signalling. This novel role for STAT3 in B cell development reveals a potential therapeutic or vaccine target for eliciting IgA humoral responses at mucosal interfaces.

Integrated membrane systems incorporating coagulation, activated carbon and ultrafiltration for the removal of toxic cyanobacterial metabolites from Anabaena circinalis

The use of integrated membrane systems (a train of treatment processes incorporating one or more membranes) is increasing globally as the technology is very effective for the production of high quality drinking water. In this investigation a laboratory scale integrated membrane system (IMS) featuring coagulation, powdered activated carbon (PAC) and ultrafiltration (UF) was investigated for the removal of an Australian strain of the cyanobacteria Anabaena circinalis and the cyanotoxin it produced. Three coagulants were compared, aluminium chlorohydrate (ACH), aluminium sulphate (alum) and an engineered aluminium coagulant referred to as high performance aluminium chlorohydrate (HPAC). PAC (Acticarb PS1000) was tested to determine adsorption of extracellular saxitoxin. Removal of A. circinalis cells was 100% by UF alone and the removal of cells prior to the membrane by coagulation reduced fouling attributed to algogenic organic material. Alum was the least efficient coagulant for removal of cells while ACH and HPAC were similar. Saxitoxin removal reached a maximum of 80% using ACH and PAC. The UF-IMS was challenged using a natural bloom of A. circinalis that occurred in the Myponga Reservoir in South Australia.

[Kleine-Levin syndrome: a case report]

The purpose of this article is to report an original clinical case whose symptoms suggest a very peculiar pathology, because of its rarity, symptomatic expression and unclear etiopathogenesis: the Kleine-Levin Syndrome (KLS). During the regression of tonsillitis concomitant with an emotional shock, the 15-year-old patient exhibited a dramatic change in behaviour, at odds with his previous state, and accompanied by hypersomnia and confusion, megaphagia, irritability, hypersexuality and mood disorders. We observed a spontaneous and total regression of the symptoms after 12 days, except for the incomplete amnesia that proved to be persistent. Four months later, further to an ethylic drunkenness, the patient presented with a new and similar episode. The patient benefited from no medicinal treatment, even in the course of hypersomnia episodes and asymptomatic periods. After a clinical presentation of this patient, we will consider this case study from a more psychopathological angle by questioning the existence of a facilitating psychological profile. The discovery of an IQ equal to 86 from the scores of WISC-IV, and the identification of constructive visual difficulties made us suspect neurological disorders, but these abnormalities were not found during the completion of the Rey Complex Figure Test. The personality profile issued from the scores at the MMPI-A assessment was ranked as barely significant (type 2-4): indeed, it showed nothing specific to this patient. Literature data show that most of the patients presenting with a KLS have been seen by a psychiatrist at the time of the disease and diagnosed as suffering from hysteria, or schizophrenia, or bipolar disorders... Because of diagnostic wanderings, some patients have, hence, received inappropriate treatments. One should pay close attention to this very rare syndrome, on the border between neurology and psychiatry, since its diagnosis is essentially based on clinical features, and carefully think about the implementation of a medicinal treatment. This unique case seems unable to support our working hypothesis about the identification of a particular psychological profile in the KLS, but the question of an underlying fragility is still worth considering. We personally think that, even though links between the KLS and bipolar disorders have been suggested, this disease has to be considered as a separate entity.

Serological and molecular comparison of Mannheimia haemolytica and Pasteurella trehalosi strains isolated from wild and domestic ruminants in the French Alps

Over a period of 17 years, 84 bacterial isolates identified as Mannheimia haemolytica or M. glucosida, and 52 isolates identified as Pasteurella trehalosi were detected in the lungs of domestic and wild ruminants in the French Alps. The isolates were serotyped according to their surface capsular antigens, and those sharing common antigens were further characterized by pulsed field gel electrophoresis. The results showed that the bacterial isolates included in the study clustered according to the host species from which they were isolated. These findings indicate that the transmission of serotypes of M. haemolytica, M. glucosida or P. trehalosi from an animal host in which they are common to another species sharing the same geographical space may be a rare epidemiological event.

Pulsed-field gel electrophoresis profiles of aeromonads isolated from healthy and diseased Helix aspersa from French snail farms

The XbaI digestion patterns of chromosomal DNA of 42 aeromonads isolated from French breeding snails during a new epizootic disease, which rapidly progressed to death during the summer of 1994, were analyzed by pulsed-field gel electrophoresis. Biochemical identification to species level was also performed. Interestingly, we found that 76% of the aeromonads isolated from diseased snails clustered into a unique pulsotype (P1) whatever their geographic origin, and were assessed to belong to Aeromonas hydrophila. Other strains belonged to Aeromonas caviae or remained unspecified. Our results provide retrospective supplementary epidemiological evidence for implication of A. hydrophila strains in the snail summer disease.

Growth and survival of Escherichia coli O157:H7 during the manufacture and ripening of raw goat milk lactic cheeses

The behaviour of Escherichia coli O157:H7 was studied during the manufacture and ripening of raw goat milk lactic cheeses. Cheese was manufactured from raw milk in the laboratory and inoculated with E. coli O157:H7 to a final concentration of 10, 100 and 1000 cfu ml(-1). E. coli O157:H7 was counted by CT-SMAC (Mac Conkey Sorbitol Agar with cefixim and tellurite) and O157:H7 ID throughout the manufacturing and ripening processes. When the milk was inoculated with 10, 100 or 1000 cfu ml(-1), counts decreased to less than 1 log(10) g(-1) in curds just prior to moulding. However, viable E. coli O157:H7 were found in cheeses throughout processing, and even after 42 days of ripening. Results indicate that E. coli O157:H7 survives the lactic cheese manufacturing process. Thus, the presence of low numbers of E. coli O157:H7 in milk destined for the production of raw milk lactic cheeses can constitute a threat to the consumer.

Comparison of three immunological methods for detecting staphylococcal enterotoxins from food

AIMS

Immunologically based assays for the detection of staphylococcal enterotoxins are numerous. These techniques include radio immunosorbent assays and enzyme-linked immunosorbent assays (ELISA), some of which are available as commercial kits. The purpose of this study was to compare the performances of three commercial immunoassays.

METHODS AND RESULTS

Two automated detection systems, VIDAS SET bioMèrieux, VIDAS SET2 bioMérieux and an ELISA method, TRANSIA PLATE Staphylococcal Enterotoxins Diffchamb were compared for detecting different quantities of purified staphylococcal enterotoxins (A, B, C2, D and E) added to food.

CONCLUSIONS

VIDAS SET2 had a greater specificity (100%) and sensitivity than VIDAS SET and TRANSIA PLATE Staphylococcal Enterotoxins. More precisely, VIDAS SET2 could detect <0.5 ng g(-1) of toxins A and B, <1 ng g(-1) of toxins C2 and E and 1 ng g(-1) of toxins D and E.

SIGNIFICANCE AND IMPACT OF THE STUDY

Because staphylococcal food poisoning (resulting from ingestion of low levels of staphylococcal enterotoxins) is one of the most common forms of foodborne illness there is a need for specific and sensitive methods for detecting these enterotoxins. VIDAS SET2 appears to be suitable for detecting staphylococcal enterotoxins from food.

Prevalence of Escherichia coli O157:H7 in industrial minced beef

AIMS

The lack of baseline data on the prevalence of Escherichia coli O157:H7 in retail minced beef in France prompted this survey of industrial minced beef production.

METHODS AND RESULTS

An automated enzyme-linked fluorescence immunoassay (ELFA), the VIDAS E. coli O157 method, was used to detect E. coli O157 in industrial minced beef samples. Confirmation of samples positive according to the ELFA was performed using an automated immunoconcentration (ICE) system, VIDAS ICE, which allows the selective capture and release of target organisms. The ICE was followed by culture on cefixime tellurite sorbitol MacConkey agar and a chromogenic medium, O157:H7 ID. Of the 3450 minced beef samples tested, 175 samples were positive with the ELFA method and, of these, four were confirmed by the ICE method. They were identified as sorbitol-negative, O157-positive, H7-positive, mobile, verotoxin-producing E. coli.

CONCLUSIONS

The prevalence of E. coli O157:H7 in industrial French minced beef was 0.12%, consistent with many other reports.

SIGNIFICANCE AND IMPACT OF THE STUDY

The low infective dose of E. coli O157:H7 presents a major threat. The main means of combating this organism are thermal destruction and good food hygiene covering activities on-farm, in the abattoir and in minced beef industries.

Prevalence of verotoxin-producing Escherichia coli (VTEC) in slurry, farmyard manure and sewage sludge in France

AIMS

The aims of the present study were to determine VTEC prevalence in manure, slurry and sewage sludge in France and to characterize the VTEC strains isolated (virulence genes and serotype).

METHODS AND RESULTS

Seven hundred and fifty-two samples from 55 farmyard manures, 136 bovine and porcine faeces, 114 slurries, 10 composts, and 437 samples from outflows of sewage wastewater treatment plants were analysed. Twenty-four percent contained isolates which were PCR positive for stx gene. Twenty-one VTEC strains were recovered from positive samples by colony hybridization: 76% of them were positive for stx(2) gene, 33% for stx(1) gene,and 19% for eae gene. One strain belonged to serotype O157:H7 and two others to serogroups O26 and O55, respectively.

CONCLUSIONS

Some of the VTEC strains isolated from environments in France should be considered as potentially pathogenic for humans.

SIGNIFICANCE AND IMPACT OF THE STUDY

Appropriate handling or use of manure, slurry and sewage sludge is necessary so that contamination of the environment and food by VTEC can be prevented.

Urinary 19-norandrosterone purification by immunoaffinity chromatography: application to gas chromatography/combustion/isotope ratio mass spectrometric analysis

The detection of exogenous 19-norandrosterone (19-NA) in urines was investigated by using gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). 19-NA is, for the first time to our knowledge, isolated from urinary matrix by specific immunoaffinity chromatography (IAC) before analysis. The sample preparation consisted of a preliminary purification of urine by solid-phase extraction after hydrolysis by beta-glucuronidase. Unconjugated 19-NA was thus isolated by IAC and directly analysed by GC/C/IRMS. Optimisation of IAC purification was achieved and the reliability of the technique for anti-doping control is discussed.

[Chemokines and defense-system cell homing]

The general properties of chemokines and their receptors are described, and the perspectives raised for cellular therapy are discussed. Specific examples are provided in the cases of the CXC chemokine SDF1 and of chemokines ligands of CCR5.

Expression of interleukin 13 receptor in glioma and renal cell carcinoma: IL13Ralpha2 as a decoy receptor for IL13

Glioma and renal cell carcinoma (RCC) cells express high affinity interleukin 13 (IL13) binding sites, but only RCC cell proliferation was inhibited by IL13. Both of these two cell types are IL2-receptor (gamma)c chain-negative. We thus used these cell models to investigate the patterns of expression of IL13Ralpha1, IL13Ralpha2, and IL4Ralpha chains and the role of IL13Ralpha2 in the response to IL13. Using new specific antibodies and flow cytometry, we observed a similar surface expression of IL4Ralpha and IL13Ralpha1 chains in most RCC and glioma cells, whereas IL13Ralpha2 was only present on five of six glioma cell lines. In all glioma cell lines, the amount of IL13Ralpha2 expression was 10 to 30 times higher than that of the two other chains. Although there was no surface or intracellular expression of IL13Ralpha2, its mRNA was detected in three of seven RCC cell lines. The expression on RCC cells of IL13Ralpha2 mRNA and/or that of high-affinity IL13 binding sites is not sufficient to predict IL13Ralpha2 protein expression. Blocking experiments showed that IL4 and IL13 strongly inhibited RCC cell proliferation through a unique receptor composed of IL4Ralpha and IL13Ralpha1 chains. Using RCC cells stably transfected with IL13Ralpha2 cDNA, we showed that the overexpression of IL13Ralpha2 decreased the response to IL13 but not that to IL4. Our results demonstrate that IL13Ralpha2 acts as a decoy receptor for IL13 and that it may exert a tight regulation of IL13 activity without impairing the IL4 response of the same cell target.

Cloning and sequencing of SOB3, a human gene coding for a sperm protein homologous to an antimicrobial protein and potentially involved in zona pellucida binding

We have previously characterized an 18-19 kDa cationic protein, SOB3, that was detected in the epididymis and localized within the acrosome and on the neck region of human spermatozoa. We suggested that it is involved in secondary sperm binding to the zona pellucida. The present study describes its purification to homogeneity by preparative electrophoresis and non-equilibrium pH gradient electrophoresis. Degenerate primers deduced from microsequencing were used to amplify a specific fragment from human epididymal RNA by reverse transcription-polymerase chain reaction (RT-PCR). This 164 bp fragment was extended by 5' and 3'-RACE to obtain the 548 bp full length cDNA. The open reading frame encodes a 170 amino acid protein. SOB3 is a single copy gene. It is 98% identical to prepro-FALL39 and 100% identical to CAP18, two human genes which were initially identified by screening a human bone marrow (lambda)gt11 library, and which encode an antimicrobial protein. Northern blots of human tissues revealed a 1 kb transcript in corpus and cauda epididymis only, while RT-PCR showed presence of the mRNA in the three epididymal regions and also in round spermatids. The above results suggest that SOB3 has two roles in sperm protection and fertilization, depending on its dual origin and final sperm localization.

Regulation of CCR6 chemokine receptor expression and responsiveness to macrophage inflammatory protein-3alpha/CCL20 in human B cells

The regulation of CCR6 (chemokine receptor 6) expression during B-cell ontogeny and antigen-driven B-cell differentiation was analyzed. None of the CD34(+)Lin(-) hematopoietic stem cell progenitors or the CD34(+)CD19(+) (pro-B) or the CD19(+)CD10(+) (pre-B/immature B cells) B-cell progenitors expressed CCR6. CCR6 is acquired when CD10 is lost and B-cell progeny matures, entering into the surface immunoglobulin D(+) (sIgD(+)) mature B-cell pool. CCR6 is expressed by all bone marrow-, umbilical cord blood-, and peripheral blood-derived naive and/or memory B cells but is absent from germinal center (GC) B cells of secondary lymphoid organs. CCR6 is down-regulated after B-cell antigen receptor triggering and remains absent during differentiation into immunoglobulin-secreting plasma cells, whereas it is reacquired at the stage of post-GC memory B cells. Thus, within the B-cell compartment, CCR6 expression is restricted to functionally mature cells capable of responding to antigen challenge. In transmigration chemotactic assays, macrophage inflammatory protein (MIP)-3alpha/CC chemokine ligand 20 (CCL20) induced vigorous migration of B cells with differential chemotactic preference toward sIgD(-) memory B cells. These data suggest that restricted patterns of CCR6 expression and MIP-3alpha/CCL20 responsiveness are integral parts of the process of B-lineage maturation and antigen-driven B-cell differentiation.

Comparison of French natural scrapie isolates with bovine spongiform encephalopathy and experimental scrapie infected sheep

We compared the glycoform pattern of the abnormal prion protein (PrP(Sc)) detected by immunoblotting in 21 sheep with natural scrapie, from 21 different outbreaks identified in France since 1996, with a bovine spongiform encephalopathy (BSE)-infected sheep. All the natural scrapie isolates had a higher molecular mass of the unglycosylated PrP(Sc) than in BSE-infected sheep. In the latter case, this molecular mass appeared identical to that found in the CH 1641 experimental scrapie strain (type C pattern), whereas in natural scrapie cases it was similar to that found in the SSBP/1 experimental scrapie strains. These results suggest that all French natural scrapie isolates studied so far would belong, as SSBP/1, to the group of scrapie cases with type A electrophoretic pattern.

Ribotyping and rapid identification of Staphylococcus xylosus by 16-23S spacer amplification

Ninety-five strains of Staphylococcus xylosus isolated from goat milk, French sausage or mice were analyzed together with 35 Staphylococcus type strains by 16-23S spacer amplification and ribotyping. The results obtained by PCR amplification of the 16-23S spacer region permitted the distinction of each type strain and additionally generated a DNA banding pattern characteristic for 93 of the 95 Staphylococcus xylosus strains. Ribotyping proved to be an efficient epidemiological tool for Staphylococcus xylosus species as it clustered the 95 strains into 23 distinct types.

Fractalkine receptor expression by T lymphocyte subpopulations and in vivo production of fractalkine in human

Expression and function of the fractalkine receptor CX3CR1 by T lymphocyte subpopulations was evaluated in healthy individuals. In CD8(+) T lymphocytes, CX3CR1 was expressed by and functional in both CD45RO(-) and CD45RO(+) cells. In CD4(+) T lymphocytes, CX3CR1 was expressed mainly by CD45RO(+) cells, and almost exclusively by activated HLA-DR(+) T lymphocytes. This receptor was functional in CD45RO(+) cells, but not in CD45RO(-) cells. Expression of fractalkine was detected by in situ hybridization and immunohistochemistry in endothelial cells of normal lung and thymus. In hyperplastic lymph nodes, fractalkine was expressed by endothelial cells of high endothelial venules and of subcapsular vessels, by follicular dendritic cells (FDC) and by some follicle lymphocytes. Fractalkine mRNA was constitutively present in the HK FDC-like cell line, and it was induced in vitro in B lymphocytes stimulated by an anti-micro or by a CD40 mAb. These findings indicate that fractalkine may contribute to the recruitment of effector T helper lymphocytes, either in peripheral tissues or in lymphoid organs. In these tissues, fractalkine and its receptor may favor contact within follicles between activated T helper lymphocytes, activated B lymphocytes and FDC, thus contributing to the maturation of the B lymphocyte response.

Cutting edge: HIV-1 Tat protein differentially modulates the B cell response of naive, memory, and germinal center B cells

Critical steps of B cell differentiation occur within lymphoid organs that are also major sites of HIV-1 replication. Because Tat can be released by infected cells, we investigated whether extracellular HIV-1 Tat modulates cell proliferation of B cells at critical stages of their differentiation. Here we show that extracellular Tat inhibited the proliferation of B cell receptor-triggered naive and memory B cells by >80% but had no effect on their CD40 mAb and IL-4-mediated proliferation. In striking contrast, Tat doubled the germinal center B cell proliferation induced by CD40 mAb and IL-4. These effects were dose dependent and required the addition of Tat at the initiation of the culture, suggesting that Tat acts on early stages of cell cycle progression. By its effects on B cell subsets, Tat might directly affect the normal B cell differentiation process in HIV-positive patients and favor the occurrence of AIDS-associated B cell lymphomas.

Antigen receptor engagement selectively induces macrophage inflammatory protein-1 alpha (MIP-1 alpha) and MIP-1 beta chemokine production in human B cells

We show herein that B cell Ag receptor (BCR) triggering, but not stimulation by CD40 mAb and/or IL-4, rapidly induced the coordinated expression of two closely related T cell chemoattractants, macrophage inflammatory protein-1 beta (MIP-1 beta) and MIP-1 alpha, by human B cells. Naive, memory, and germinal center B cells all produced MIP-1 alpha/beta in response to BCR triggering. In contrast to MIP-1 alpha/beta, IL-8, which is spontaneously produced by germinal center B cells but not by naive and memory B cells, was not regulated by BCR triggering. Culturing follicular dendritic cell-like HK cells with activated B cells did not regulate MIP-1 alpha/beta production, but it did induce production of IL-8 by HK cells. Microchemotaxis assays showed that CD4+CD45RO+ T cells of the effector/helper phenotype actively migrated along a chemotactic gradient formed by BCR-stimulated B cells. This effect was partially blocked by anti-MIP-1 beta and anti-CC chemokine receptor 5 Ab, but not by anti-MIP-1 alpha Ab suggesting that MIP-1 beta plays a major role in this chemoattraction. Since maturation of the B cell response to a peptide Ag is mostly dependent on the availability of T cell help, the ability of Ag-stimulated B cells to recruit T cells via MIP-1 alpha/beta, may represent one possible mechanism enabling cognate interactions between rare in vivo Ag-specific T and B cells.

Identification by 16S rDNA fragment amplification and determination of genetic diversity by random amplified polymorphic DNA analysis of Pasteurella pneumotropica isolated from laboratory rodents

Pasteurella pneumotropica is an opportunistic bacterium frequently isolated from colonies of various laboratory rodents. Identification of this species, including its differentiation into two distinct biotypes (Jawetz and Heyl), is usually based on the use of conventional bacteriologic methods. In this study, a 16S rDNA fragment amplification procedure was developed for use as an alternative method for identification and differentiation of P. pneumotropica. Polymerase chain reaction (PCR) products were two distinctive fragments of 937 and 564 bp specific for biotypes Jawetz and Heyl, respectively. Specificity of PCR products could be achieved by EcoRI cleavage, leading to 596 plus 341-bp and 346 plus 218-bp fragments for each of the amplification products. Use of this procedure confirmed identification of 34 field isolates and allowed definitive identification of some strains that could not have been done by use of bacteriologic examinations. Field isolates subjected to random amplified polymorphic DNA (RAPD) analysis had high genetic diversity among biotype Jawetz strains in contrast to biotype Heyl strains. In conclusion, RAPD could represent an additional means for identification of ambiguous strains of biotype Heyl and a valuable epidemiologic tool for identification of biotype Jawetz strains of P. pneumotropica.

Pulsed-field gel electrophoresis is more efficient than ribotyping and random amplified polymorphic DNA analysis in discrimination of Pasteurella haemolytica strains

One hundred thirty-three strains of Pasteurella haemolytica of both biotypes (90 and 43 strains of biotypes A and T, respectively) and almost all the serotypes were subjected to ribotyping, random amplified polymorphic DNA (RAPD) analysis, and pulsed-field gel electrophoresis (PFGE) analysis for epidemiological purposes. A total of 15 patterns recorded as ribotypes HA to HO were found for the P. haemolytica biotype A strains, with ribotypes HA, HC, and HD being encountered most often (66 strains [74%]); and 20 ribotypes, designated HA' to HT', that were clearly distinct from those observed for biotype A strains were observed for strains of biotype T. RAPD analysis generated a total of 44 (designated Rp1 to Rp44) and 15 (designated Rp1' to Rp 15') unique RAPD patterns for biogroup A and biogroup T, respectively. Analysis of the data indicated that a given combined ribotype-RAPD pattern could be observed for biotype A strains of different serotypes, whatever the zoological or geographic origin, whereas this was not the case for biotype T strains. PFGE appeared to be more efficient in strain discrimination since selected strains from various zoological or geographical origins harboring the same ribotype-RAPD group were further separated into unique entities.

CD80 expression is decreased in hyperplastic lymph nodes of HIV+ patients

A centrofollicular hyperplasia is present within secondary lymphoid organs during all the asymptomatic phase of the HIV disease. Although this hyperplasia has been well characterized by histological studies, the nature of the phenotypic alterations in B cell populations occurring within HIV+ lymphoid organs remains to be established. By immunohistochemistry, we thus investigated whether a particular germinal center (GC) B cell population was increased during HIV-induced hyperplasia and whether any phenotypic change was specific to HIV-1 infection. As compared to normal tonsils (three cases) and HIV- hyperplastic lymph nodes (eight patients), we observed a loss of GC polarization in all HIV+ sections (11 patients), with no more delineation between dark and light zones, as shown by Ki67, CD10, CD77, CD95 and CD86 staining. In contrast to CD86 expression which remained as intensive in HIV+ as in HIV- lymph nodes, CD80 staining was strongly decreased in GC of HIV+ lymph nodes but not in their extrafollicular zones. The loss of CD80 expression from CD19+ B cells was also observed by cytometric analysis of cell suspensions of three HIV+ patients. Although we found no evidence of an increase in a particular GC B cell subset in HIV-1-induced hyperplasia, the strong GC disorganization observed may induce impaired cell-cell interactions and thus participate in the loss of CD80 antigen. In contrast to HIV- situations where CD80 and CD86 was similarly expressed on B cells, the lower level of CD80 expression in HIV+ GC may favor Th2 T cell responses through CD86-CD28 interactions.

Use of evidence in the process of practice change in a clinical team: a study-forming part of the Autocontrol Project

The Autocontrol Project is concerned with the accessing, processing and communication of high quality information so that a clinical team can make and implement decisions for practice change, and then evaluate if improvement has been achieved. High quality information is used as evidence for change. In this study, we have evaluated how evidence is used by a clinical team to explain an identified problem of inappropriate use of blood gas tests. In an experimental study of the Surgical Intensive Care Unit, video recordings of team meetings of nurses and doctors were undertaken, structured according to a problem-based format. Evidence of current practice patterns derived from the hospital information system, as well as the results of a questionnaire to the unit's staff about knowledge and use of blood gas measurements, were supplied to the participants beforehand. At the second meeting, the output of the first meetings and a summarised analysis of pertinent literature were made available. This second meeting was required to finalise the list of causes of inappropriate blood gas use and propose pragmatic strategies for practice change. The video data of the meetings were coded to analyse the use of evidence, the categories of causes, issues and solutions proposed, and the quality of team interaction. The results indicate that in order to achieve consensus, the team used different types of evidence, including objective evidence of practice patterns, personal experience about direct and indirect organisational influences, and literature-based research evidence of best practice. Furthermore, group dynamics were favoured by the problem-based meeting structure, and a high level of cognitive critiquing between team members was observed. This research suggests that a combination of approaches involving identification of both operational factors (e.g. appropriate access to different types of evidence and meeting structure) and cognitive and behavioural approaches (e.g. ensuring expression of different viewpoints) is needed to support strategic decision-making for practice change in a clinical unit. This combined approach should favourably influence the provision of an effective and efficient evidence support environment for the clinical team.

B cell-driven HIV type 1 expression in T cells: an essential role of CD86 costimulatory molecule

During HIV-1 infection, HIV-1 is sequestered and actively replicates within lymphoid organs, mainly in areas essential for antigen-specific T-B interactions. We investigated whether cognate T-B interactions not only drive humoral response to HIV-1 but also enhance viral replication. Costimulation of in vitro HIV-1-infected tonsillar T cells with autologous or allogeneic activated B cells increased both viral replication and T cell proliferation. Addition of CD86 MAb to cocultures inhibited most p24 (84 +/- 12%, n = 13) and IL-2 (99 +/- 2%, n = 6) production, decreased T cell proliferation by 46 +/- 15% (n = 13), and decreased TNF-alpha and IFN-gamma production by 67 +/- 17% (n = 6) and 53 +/- 6% (n = 6), respectively. In contrast, CD80 MAb, which strongly inhibited IL-2 production (77 +/- 10%, n = 6), moderately downregulated p24 and TNF-alpha production (29 +/- 21%, n = 13 and 34 +/- 10%, n = 6, respectively) and did not decrease T cell proliferation (8 +/- 10%, n = 13) or IFN-gamma production (14 +/- 13%, n = 6). We thus showed that B cells deliver a potent CD86/CD28 costimulatory signal that induces T cell proliferation and simultaneously enhances HIV-1 replication. CD86+ B cells, mainly localized within the light zone of germinal centers, might thus favor active in situ replication of HIV-1 in response to each new challenge by T-dependent antigens.

Evaluation of the VIDAS methodology for detection of Escherichia coli O157 in food samples

An automated enzyme-linked fluorescence immunoassay (ELFA), the VIDAS E. coli O157 method, was compared with immunomagnetic separation (IMS) followed by culture on cefixime tellurite sorbitol MacConkey agar (CT-SMAC) for detecting Escherichia coli O157 in artificially and naturally contaminated food samples including raw milk cheeses, poultry, raw sausages, and ground beef retail samples. Confirmation of the samples positive according to the ELFA was performed by use of an automated immunoconcentration system, VIDAS ICE, which allows selective capture and release of target organisms. A total of 496 retail food samples were examined. Seventeen food samples gave positive values with the ELFA method, and among them 9 food samples were confirmed by the ICE method. Eight were shown to contain sorbitol-positive, O157-positive, H7-negative, motile, non-verotoxin-producing E. coli. The ninth positive sample contained an O157-positive, H7-negative, sorbitol-negative, non-verotoxin-producing E. coli. The IMS technique only allowed confirmation of this sorbitol-negative, non-verotoxin-producing E. coli O157.

Behaviour and enterotoxin production by Staphylococcus aureus during the manufacture and ripening of raw goats' milk lactic cheeses

To study the possible presence of staphylococcal enterotoxin A in raw goats' milk lactic cheese, milk was inoculated with an enterotoxigenic Staphylococcus aureus strain to a final concentration of 4, 5 and 6 log(cfu/ml). Cheese was prepared following industrial specifications and ripened for 42 d. Detection of the enterotoxins was by the Vidas Staph enterotoxin test (BioMérieux) and by an indirect double-sandwich ELISA technique using anti-enterotoxin monoclonal antibodies. Staphylococcal counts declined markedly after draining, and by the end of ripening they had disappeared from some cheeses. In contrast, aerobic mesophilic organisms grew well. The level of staphylococcal enterotoxin A recovered varied from 1 to 2.5 ng/g cheese made with an initial population of 10(5) or 10(6) cfu/ml. Only traces of enterotoxin A (0.5 ng/g) were detected in cheeses made with the lowest Staph. aureus inoculum used in this study. Enterotoxin A was also detected in cheeses from which Staph. aureus had disappeared.

Ribotyping of Staphylococcus caprae isolated from goat milk

The usefulness of the API-STAPH system and a method based on ribosomal fingerprinting was evaluated by studying 89 coagulase-negative staphylococci isolated from goat milk. The bacteria were supposed to belong to the species Staphylococcus caprae. The results obtained from the API-STAPH system showed variations in their phenotypic features. DNA cleavage with EcoRI yielded six ribotypes and three distinct patterns were generated when the DNA of the strains was digested with HindIII. Forty-six strains were correctly characterized as S. caprae by the two methods. In addition, 37 isolates having atypical biochemical profiles with the API-STAPH system were confirmed as being S. caprae by the ribotyping. Three strains remained unclassified by both methods. Ribotypes generated by HindIII were found to be the most informative for species determination, whereas the number of bands generated by EcoRI indicated the usefulness of this enzyme in S. caprae typing.

Exoprotein and slime production by coagulase-negative staphylococci isolated from goats' milk

Milk from mastitis-free goats from French herds was examined for the presence of coagulase-negative staphylococci (CNS), and 165 positive isolates were evaluated for their capacity to produce exoproteins. Most isolates were identified as Staphylococcus caprae (N = 91) or S. xylosus (N = 36), but members of at least nine other species were present. Overall, some 57% of isolates produced toxins with phenotypic properties of alpha-hemolysin, and 75% produced toxins resembling S. aureus beta and/or delta-hemolysins. Thermostable desoxyribonuclease (TNAse) was secreted by 29% of isolates and thermolabile DNAse by 66%. Slime was produced by 42% of our cultures and, although none of them showed activity to insoluble elastase, over 70% lysed the soluble substrate. No clinical consequences were observed to correlate with exoprotein production, which proved to be inconstant within individual CNS species.

Isolation and identification of Salmonella species from chelonians using combined selective media, serotyping and ribotyping

Thirty-two faecal samples from various pet chelonians were bacteriologically examined using various combinations of selective media for Salmonella detection. Strains identified as Salmonella were clustered by rRNA gene restriction pattern (ribotyping) analysis prior to serological typing. The combination of selenite broth and Rambach or Salmonella-Shigella agars gave the maximum rate of Salmonella recovery. Of the 32 samples examined, 13 (40%), were positive for Salmonella. Five serovars were identified, Muenchen, Rubislaw, Newport, Ferruch and a non-motile O:4,5,12, with Salmonella Muenchen the most common. This result indicates that biochemical characterization combined with ribotyping prior to serotyping can contribute to Salmonella detection on a large scale.

Detection of Escherichia cole O157 in French food samples using an immunomagnetic separation method and the VIDAS E. coli O157

Two commercially available screening methods, an automated enzyme-linked fluorescent immunoassay (VIDAS E. coli O157) and an immunomagnetic separation followed by culture onto cefixime tellurite sorbitol MacConkey agar (CT-SMAC), were compared for detection of Escherichia coli O157 in naturally and artificially contaminated food samples. A total of 250 naturally contaminated food samples, including raw milk cheeses, poultry, raw sausages and ground beef retail samples, were examined. Four poultry, one raw sausage and one ground beef sample were found to be positive for E. coli O157 by both methods. Of the six positive samples, five were shown to contain sorbitol-positive, O157-positive, H7-negative, motile and non-verotoxin-producing E. coli.

Thirty cases of duplication of the thumb. Operative results

Thirty cases of duplication of the thumb have been seen during a period of 8 years. Twenty-four children underwent surgery for a total of 25 operations, and these are reviewed after a follow-up of at least a year. Wassel's type IV was the most frequent type, occurring in 14 cases. There were 23 primary operations, and 2 reoperations for frontal deviation, which were secondary to operations done elsewhere. The average age at the time of operation was 16 months, the mean follow-up is 4 years (1 to 8 years). The results are analyzed according to Wassel's criteria. Regardless of the location of the duplication, function is unaffected, the structure of the thumb is good, and the parents are satisfied. However, examination revealed some loss of mobility in 10 cases, shortening of the thumb in 5 cases, instability of the collateral ligament in 3 cases and axis deviation in 10 cases. Six of these were clinodactyly at the IP, 1 a clinodactyly at the MP and 3 Z-shaped deformities at the IP and MP. The two reoperations were done to correct a significant loss of alignment, and in each the result was upgraded from "poor" to "fair". It seems that the end results are determined at the original operation which should be done before the 18th month. The thumb with the least function, usually on the radial side, is resected and the remaining component reconstructured. This includes centralization of the insertions of the extrinsic muscles, and reinsertion of the thenar muscles. Immobilization by pinning is usually done due to the need for an osteotomy during the surgery for realignment of the axis of the thumb. It must, however, always be remembered that this surgery is cosmetic rather than functional.

Molecular and phenotypic features of aeromonads isolated from snails (Helix aspersa) affected with a new summer disease

Forty-four aeromonads were isolated during the summer of 1994 from snails (Helix aspersa) affected or not by a newly described disease. Snta 1 rRNA gene restriction patterns (ribotyping) and nine selected conventional phenotypic tests were performed to retrospectively determine relationships among these isolates regarding the disease. Results from ribotyping were found highly discriminant in strain differentiation and suggest the possible existence of a group of Aeromonas associated with the disease. Biochemical and molecular characterizations indicated that most of these disease-associated aeromonads could belong to the phenospecies A. hydrophila. Phenospecies of aeromonads from healthy snails were distinct from those isolated from diseased snails and could be identified as A. caviae or remained undetermined. To the authors' knowledge, this is the first report of a probable pathogenic aeromonad found in snails, extending the host-pathogen spectrum of Aeromonas.

Data collection and information presentation for optimal decision making by clinical managers--the Autocontrol Project

The Autocontrol methodology has been developed in order to support the optimisation of decision-making and the use of resources in the context of a clinical unit. The theoretical basis relates to quality assurance and information systems and is influenced by management and cognitive research in the health domain. The methodology uses population rather than individual decision making and because of its dynamic feedback design promises to have rapid and profound effect on practice. Most importantly the health care professional is the principle user of the Autocontrol system. In this methodology we distinguish three types of evidence necessary for practice change: practice based or internal evidence, best evidence derived from the literature or external evidence concerning the practice in question, and process based evidence on how to optimise the process of practice change. The software used by the system is of the executive decision support type which facilitates interrogation of large databases. The Autocontrol system is designed to interrogate the data of the patient medical record however the latter often lacks data on concomitant resource use and this must be supplemented. This paper reviews the Autocontrol methodology and gives examples from current studies.

Moraxella boevrei sp. nov., a new Moraxella species found in goats

Six Moraxella-like strains that formed a phenotypically homogeneous group were isolated from the nasal flora of healthy goats. Total genomic DNA-DNA hybridization, rRNA gene restriction pattern, DNA base composition, and genetic transformation studies were performed to determine the relationships of these bacteria to species belonging to the genus Moraxella and other fastidious gram-negative species. The new group of isolates was very homogeneous, as shown by rRNA gene restriction fragment length patterns (ribotyping), and these organisms displayed high relative binding ratios (RBRs) to each other in DNA-DNA hybridization experiments (RBRs, > or = 58%) but distinctly lower levels of DNA homology with all other species investigated. However, the RBRs obtained with species of the genus Moraxella were higher than the RBRs obtained with all other gram-negative strains examined. Although the new strains had most of the Moraxella bovis phenotypic characteristics except nitrate reduction, quantitative and qualitative genetic transformation data led to the conclusion that they belong to a distinct new cluster in the genus Moraxella. The results of this study, combined with the general morphological and phenotypic profiles of the new strains, are consistent with the creation of a new Moraxella species, for which the name Moraxella boevrei is proposed. Strain 88365 (= ATCG 700022 = CCUG 35435 = NCTC 12925 = CIP 104716) is the type strain of M. boevrei.

Regulation of platelet-activating factor receptor expression in human B cells and B cell lines

We extended our previous data regarding the modulation of human platelet-activating factor receptor (hPAF-R) expression on human B cell lines as well as normal B cells. First, we showed that hPAF-R mRNA was present in B cell lines expressing membrane hPAF-R, but was absent from cell lines devoid of hPAF-R. Second, enhanced hPAF-R membrane expression induced in IM9 line by IL4 was preceeded by hPAF-R mRNA accumulation that was detectable by 8 h and which peaked at 24 h. Similar results were observed for 10 nM platelet-activating factor treatment, which increased hPAF-R mRNA content up to 120% at 48 h, whereas hPAF-R membrane expression was up-regulated by 130%. Third, our data indicate that functional hPAF-R are expressed on resting, as well as on activated, B cells and that B cell activation is required for maintaining hPAF-R membrane and mRNA expression. Thus, in normal B cells, as well as in B cell lines, transcriptional regulation and/or messenger stability control hPAF-R expression.

IL4 and IL13 receptors share the gamma c chain and activate STAT6, STAT3 and STAT5 proteins in normal human B cells

IL13 induces the same biological effects as IL4 in normal human B cells. We show that as in the IL4R complex, both IL4R alpha and IL2R gamma c are components of the IL13R and that both cytokines induced STAT6, STAT3 and STAT5 activation in B cells. In spite of this similar downstream signalling, IL4 and IL13 used a different set of Janus kinases: IL13 is unable to activate JAK1 and JAK3.

Cytokine response of B lymphocytes from splenic lymphoma with villous lymphocytes: correlation with TNF-RII (p75) and CD11c expression

We studied the immunophenotype and the functional reactivity to cytokines of blood cells from eight patients with Splenic Lymphoma with Villous Lymphocytes (SLVL). Cells from all cases exhibited moderate to high levels of membrane immunoglobulin, CD22 and CD40 antigens and light chain restriction (kappa/lambda: 1.7/1). CD44, CD54 and CD11b expression was detected in all cases whereas CD11c was expressed in only four cases (50%). CD11c+ cells lacked CD21 and CD23 expression whereas CD11c cells expressed both these antigens. Cells from most patients (7/8) responded to IL2 whereas only four responded to IL4 and three to TNF alpha. The response to TNF alpha correlated with spontaneous TNF-RII and CD11c expression. Although two days of culture induced the TNF-RII expression in CD11c cells, they remained unresponsive to TNF alpha. These two groups of SLVL patients also differed by IL10 mRNA content: the former (CD11c+, TNF-RII+) contained TNF alpha and IL10 mRNA whereas the latter (CD11c, TNF-RII) lacked IL10 mRNA, even after two days of culture. There were thus two groups of SLVL patients: CD11c+ and CD11c, exhibiting different patterns of cytokine response and production. These groups may correspond to different cell origins or different progression stages of the disease.

CD40/CD40L interactions and cytokines regulate HIV replication in B cells in vitro

Using our in vitro model of normal B cell infection, we investigated whether cellular interactions and/or cytokines directing the B cell response also regulate HIV replication. Phorbol esters and CD40 Ab plus IL4, added prior to infection, substantially increased subsequent viral replication. Postinfection, IL2 with or without IL4 and, to a lesser extent, CD40/CD40L interactions enhanced viral replication. In contrast, IL10 down-regulated HIV replication induced by cytokines, without affecting spontaneous or CD40 Ab-induced replication. Both enhancing and inhibitory effects of cytokines on viral replication were independent of their ability to modulate B cell proliferation. Thus, these two phenomena seem to be independently regulated in human B cells.

Mechanisms of opsonized HIV entry in normal B lymphocytes

Using our in vitro model of normal B cell infection that functions with low doses of HIV but requires virus opsonization by seropositive patient serum, and complement, we analyzed what receptors allowed virus entry. Here, we show that HIV infection of B cells occurs through 2 major receptors: the CD4 antigen and the CR1/CR2 complex. These 2 pathways work independently since a complete inhibition of virus entry requires both CD4 and CD21/CD35 blockade on CD4dim tonsillar B cells whereas only the latter is critical on CD4-negative B cells.

Moraxella caprae sp. nov., a new member of the classical Moraxellae with very close affinity to Moraxella bovis

Eight phenotypically homogeneous Moraxella-like strains were isolated from the nasal flora of healthy goats. Total genomic DNA-DNA hybridization, DNA base composition determination, and genetic transformation studies were performed to determine the relationships of these bacteria to the classical moraxellae. The eight new isolates exhibited very high levels of genetic affinity to Moraxella bovis, as shown by quantitative and qualitative genetic transformation data, and exhibited high DNA-DNA relative binding ratios to each other (63% or more) but lower levels of DNA homology with all of the other species investigated, including the closely related classical moraxellae. Our results, combined with the general morphologic and phenotypic profiles of these organisms, indicate that they should be classified with the classical moraxellae, and we propose the name Moraxella caprae for them. Strain 8897 (= CCUG 33296 [corrected] = NCTC 12877) is the type strain of M. caprae.

JAK3 associates with the human interleukin 4 receptor and is tyrosine phosphorylated following receptor triggering

In human B cells, interleukin 4 (IL4) acts in regulating proliferation, antigen expression, isotype switching and differentiation. These different effects are mediated through the IL4R complex including the IL2R gamma chain (gamma c) and a specific p130/140 binding unit referred below as human Interleukin 4 Receptor (IL4-R). Here, we studied the signal transduction events following IL4R activation and leading to CD23 expression on resting B cells. We demonstrate that IL4R triggering induced the tyrosine phosphorylation of JAK3 and of a p170 protein. Coimmunoprecipitation of JAK3 with the IL4R suggests a physical association which exists prior to IL4R complex stimulation. Orthovanadate treatment, while having no effect on IL4-induced p130 phosphorylation, leads to the hyperphosphorylation of the p170 and inhibits IL4-induced CD23 expression. These suggest that two mandatory steps exist in early IL4 signaling: one controlled by JAK3 activation and the other by the p170 phosphoprotein.

Identification of Moraxella bovis and related species from calves with IBK and goats by qualitative genetic transformation assay

Eight Moraxella bovis strains isolated from bovine pink eye, 16 Moraxella bovis related strains isolated from healthy goats nasal flora, one nonhemolytic Moraxella sp. isolated from bovine conjunctivitis and different collection strains of Moraxella and Branhamella genus were studied through the combined use of qualitative genetic transformation assay and the ability to grow on a moraxella bovis defined medium (medium MB). Crude DNA extracted from the strains studied were used to transform two mutant auxotroph competent strains of Moraxella bovis CIP 103741 and CIP 103743. Non-specific positive transformation was obtained with mutant assay strain CIP 103743 when treated with DNA from caprine or bovine Moraxella strains, collection strains of Moraxella bovis, Moraxella lacunata, Moraxella nonliquefaciens and strains of Branhamella genus, whereas specific transformation was observed with mutant assay CIP 103741 when treated only with DNA from all the Moraxella bovis (collection and clinical isolates) and 14 of the 16 caprine Moraxella bovis related strains. The specificity and the simplicity of the test make it suitable for use in clinical laboratories.