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Biomedical subjects

M Jansze

Publications and source records attributed to M Jansze.

At least 19 recordsLinked to original sources
PubMed1995

Assessment of complement-mediated killing of Moraxella (Branhamella) catarrhalis isolates by a simple method.

Recently, we showed that complement resistance is an important virulence factor of Moraxella (Branhamella) catarrhalis. Our study used a serum bactericidal assay to determine complement resistance in M. catarrhalis. Although the serum bactericidal assay is considered the "gold standard" for determining complement resistance, it is laborious and time-consuming and therefore not well suited for large-scale studies. Using a large number (n = 324) of M. catarrhalis isolates obtained from the sputa of patients with lower respiratory tract infections (n = 200) and young carriers (n = 124), we assessed the value of a simple "culture-and-spot" test as an alternative to the serum bactericidal assay. For both groups of isolates, the degree of concordance between the two tests used was very significant (P < 0.0001). The agreement between the two assays was estimated to be "excellent beyond chance" (as determined by Cohen's kappa test). The culture-and-spot assay is a valuable alternative to the serum bactericidal assay, not only for screening purposes as shown here but also for studying the mechanism of complement resistance in M. catarrhalis at the molecular level.

Bacteriological Techniques↗
PubMed1994

Differences in complement activation between complement-resistant and complement-sensitive Moraxella (Branhamella) catarrhalis strains occur at the level of membrane attack complex formation.

The mechanism of resistance to human complement-mediated killing in Moraxella catarrhalis was studied by comparing different complement-sensitive and complement-resistant M. catarrhalis strains in a functional bystander hemolysis assay and an enzyme-linked immunosorbent assay (ELISA) for soluble terminal complement complexes. Complement-resistant stains appeared to activate complement to the same extent as, or even slightly better than, complement-sensitive strains. This indicates that complement-resistant strains do not inhibit classical or alternative pathway activation but interfere with complement at the level of membrane attack complex formation. A clear difference in dose-response curves for resistant and sensitive strains was observed both in the bystander hemolysis assay and in the ELISA. Complement-resistant strains showed optimum curves, whereas complement-sensitive strains gave almost linear curves. We conclude that resistant strains bind and/or inactivate one of the terminal complement components or intermediates involved in membrane attack complex formation. Trypsin, known to abolish complement resistance, changed the optimum dose-response curve of a resistant strain to a linear one, which strongly suggests that complement resistance is mediated by an M. catarrhalis-associated protein. This protein acts directly or through the binding of a terminal complement inhibitor present in serum.

Bacterial Proteins↗
PubMed1993

Detection of toxigenic Clostridium difficile in fecal samples by colony blot hybridization.

A hybridization assay for detection of toxigenic Clostridium difficile in fecal samples was developed and compared with the classical tissue culture cytotoxicity assay. A DNA fragment probe specific for the toxin B gene of Clostridium difficile was synthesized by the polymerase chain reaction and labelled with digoxigenin. Fecal samples were cultured for 24 hours, replica-plated and hybridized with the probe. The hybridization assay had a sensitivity of 100%, specificity of 96.7%, positive predictive value of 86.7% and negative predictive value of 100% compared with the cytotoxicity assay.

Base Sequence↗
PubMed1993

Frequency of enterovirulent Escherichia coli in diarrhoeal disease in The Netherlands.

To assess the role of enterovirulent Escherichia coli in The Netherlands, faecal samples of 279 patients (108 children, 171 adults) with diarrhoea and 100 healthy controls were investigated in a prospective study. Enterovirulent Escherichia coli were identified by hybridization with five different non-radioactively labelled DNA probes specific for enteropathogenic Escherichia coli (EPEC), verocytotoxin producing Escherichia coli (VTEC) and enterotoxigenic Escherichia coli (ETEC). The rate of isolation of EPEC was 6.5% in patients with diarrhoea and 2.0% in asymptomatic persons. During the study period, no VTEC were isolated from patients with diarrhoea. ETEC were isolated from two persons, both of whom had experienced diarrhoea and had returned from travel in (sub)tropical areas. Our results suggest that diarrhoea is sporadically caused by ETEC among the indigenous population of The Netherlands, and is mainly associated with travel in endemic areas. Furthermore, the presence of EPEC probe-positive strains in the stool need not always be accompanied by symptoms of diarrhoea.

Adult↗
PubMed1993

Detection of enterovirulent Escherichia coli associated with diarrhoea in Seville, southern Spain, with non-radioactive DNA probes.

To assess the role of diarrhoeagenic Escherichia coli in Southern Spain, faecal samples from 135 patients with diarrhoea and 40 healthy subjects from Seville, Andalusia, were investigated. In this prospective study, enterovirulent E. coli were identified by hybridisation with five non-radioactive DNA probes specific for enterotoxigenic E. coli (ETEC), enteropathogenic E. coli (EPEC) and verocytotoxin-producing E. coli (VTEC). Probe-positive strains were isolated from four patients (3%) with diarrhoea and from none of the healthy controls. Two patients harboured ETEC and two patients had EPEC probe-positive strains in their faeces. No VTEC were isolated during this study. Salmonella spp. were the most frequently identified enteric pathogens, accounting for 10% of the cases, followed by Campylobacter jejuni (3%) and diarrhoeagenic E. coli (3%). This study indicates that enterovirulent E. coli play a modest role in the aetiology of diarrhoea among the indigenous population of Southern Spain.

Adult↗
PubMed1993

Comparison of typing methods for Clostridium difficile isolates.

A simple discriminative typing method for Clostridium difficile has been developed. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of whole-cell proteins and restriction enzyme analysis are relatively simple techniques but are difficult to evaluate, especially the restriction enzyme analysis. Immunoblotting and restriction fragment length polymorphism typing facilitate simple discrimination of patterns.

Bacterial Typing Techniques↗
PubMed1992

CD16 on human gamma delta T lymphocytes: expression, function, and specificity for mouse IgG isotypes.

We examined the expression, the signal transduction capacity and mouse IgG-isotype specificity of CD16 on human gamma delta T cells. CD16 is expressed by the majority of gamma delta T cells in peripheral blood and by part of the gamma delta T cell clones. The amount of CD16 expressed on gamma delta T cell clones varied considerably with passaging of the cells, but was always significantly less than on freshly isolated gamma delta T cells. Like CD16 on CD3- CD16+ natural killer (NK) cells, CD16 on gamma delta T cells can act as an activation site triggering cytotoxic activity. CD16+ gamma delta T cell clones exerted antibody-dependent cellular cytotoxicity (ADCC) which could be blocked by anti-CD16 mAb. ADCC activity of gamma delta T cell clones was also inhibited by anti-CD3 mAb, suggesting a functional linkage between the CD16 and CD3 activation pathways. MAb directed against CD16 induced lysis of Fc gamma R+ target cells by CD16+ gamma delta T cell clones. The mouse IgG-isotype specificity of CD16 on gamma delta T cells was analyzed using isotype switch variants of a murine anti-glycophorin A mAb in EA rosette assays, and was found to be identical to that of CD16 on CD3- CD16+ NK cells, i.e., highest affinity for mIgG2a, intermediate affinity for mIgG2b, and undetectable binding of mIgG1-sensitized erythrocytes. CD16 was partly modulated from the cell surface of both gamma delta T cells and NK cells after rosette formation with mIgG2a-sensitized erythrocytes, indicating that the rosette formation was indeed mediated via the CD16 molecule.

Animals↗
PubMed1991

Nontoxigenic strains of Clostridium difficile lack the genes for both toxin A and toxin B.

A total of 39 toxigenic and 20 nontoxigenic strains of Clostridium difficile were tested for the presence of either toxin A or toxin B by the polymerase chain reaction (PCR). All toxigenic strains produced cytotoxin as assayed by using highly sensitive fetal lung fibroblasts and were positive for toxin A as well as toxin B in the PCR assay. All nontoxigenic strains failed to produce toxin and were negative in the PCR assay. This study shows that nontoxigenic strains of Clostridium difficile lack the toxin A as well as the toxin B gene.

Bacterial Proteins↗
PubMed1990

Effect of protease inhibitors on human monocyte IgG Fc receptor II. Evidence that serine esterase activity is essential for Fc gamma RII-mediated binding.

We have shown previously that certain proteases can modulate the affinity of human Fc gamma RII for IgG. To study whether proteolytic events not only increase FcR affinity, but are essential for Fc gamma R functioning, we evaluated the effect of different protease inhibitors on binding mediated by two classes of human monocyte IgG FcR. These R, Fc gamma RI and Fc gamma RII, can be analyzed selectively in rosetting assays by employing E sensitized by either human IgG or mouse IgG1. Rosetting by both classes of R was inhibited profoundly by incubation of monocytes with different types of serine protease inhibitors such as diisopropylfluorophosphate, PMSF, or N alpha-tosyl-L-lysyl-chloromethylketone. The type II Fc gamma R was much more sensitive to inhibition than Fc gamma RI. We, therefore, studied these effects in more detail by using cell line K562, which expresses only Fc gamma RII. PMSF, diisopropylfluorophosphate, and N alpha-tosyl-L-lysyl-chloromethylketone were, again, inhibiting Fc gamma RII-mediated binding dose-dependently, whereas several inhibitors of metal, aspartic, or thiol proteases proved ineffective. Furthermore, Fc gamma RII-mediated rosetting on both cell types was profoundly inhibited by the addition of different small synthetic substrates of serine esterases. In an attempt to discriminate whether the proteolytic event is an intra- or extracellular process, macromolecular antiproteases such as soybean or ovomucoid trypsin inhibitor or alpha 1-antiprotease were tested. Fc gamma RII-mediated binding by K562 cells was not susceptible to macromolecular antiproteases, in contrast to monocytes. In the presence of drugs which interfere both with receptor recycling and intracellular traffic between endosomal compartments (e.g., primaquine or monensin), the effects of inhibitors were largely abrogated. This showed that endocytosis of inhibitors might be essential, indicating the proteolytic event to be intracellular. Our findings suggest that human monocyte Fc gamma RII-mediated functioning is dependent upon the action of one or more serine proteases.

Antigens, Differentiation↗
PubMed1990

Measurement of the humoral immune response against Streptococcus pneumoniae type 14-derived antigens by an ELISA and ELISPOT assay based on biotin-avidin technology.

A Streptococcus pneumoniae type 14-specific ELISA and ELISPOT assay have been developed based on the use of biotinylated type 14 capsular polysaccharide (S14PS-biotin). A major advantage of this application over other methods is the use of 10-100-fold less antigen than that reported in the literature for other similar assays. Moreover, the prepared biotinylated polysaccharides are very stable and it is possible to use the same procedures for other pneumococcal polysaccharide antigens (e.g., S6BPS) with no major changes necessary in the ELISA and ELISPOT protocols. Furthermore, a simple thin layer chromatography method has been developed as a method for quality control of the biotinylated polysaccharide. Immunization with the thymus-independent antigen S14PS resulted in the induction of IgM spot-forming cells (SFC) and antibodies while S14PS-protein conjugates induced a thymus-dependent response. The immune response to the conjugates was enhanced by the addition of the adjuvant Quil A resulting in high levels of both IgG SFC and antibodies at day 14 after immunization. The developed assays are reliable and reproducible tools for studying the humoral immune response against Streptococcus pneumoniae type 14 capsular polysaccharide derived antigens.

Animals↗
PubMed1989

Modulation of the immune response to pneumococcal type 14 capsular polysaccharide-protein conjugates by the adjuvant Quil A depends on the properties of the conjugates.

Streptococcus pneumoniae type 14 capsular polysaccharide-bovine serum albumin (S14PS-BSA) conjugates were prepared by water-soluble-carbodiimide-mediated condensation with or without the use of N-hydroxy-sulfosuccinimide. The immunogenicities of the capsular polysaccharide (S14PS) and of the conjugates were studied in (CBA/N x BALB/c)F1 mice and in female BALB/c mice. The response in these mice indicates that S14PS could be classified as a thymus-independent type 2 antigen. Coupling of S14PS to BSA improved the immunogenicity of this polysaccharide, and an immunoglobulin G memory response was evoked. Conjugation with N-hydroxysulfosuccinimide resulted in a product with a higher polysaccharide/protein ratio. This conjugate induced a greater immune response than did the classical conjugate. Quil A enhanced the immune response to S14PS and to most S14PS-BSA conjugates. The enhancement of the immune response to the conjugates seemed to depend on the coupling procedure. Our results indicate that for the construction of immunostimulating complexes based on polysaccharide or oligosaccharide-protein conjugates, attention should be paid to the degree of cross-linking of the antigens involved.

Adjuvants, Immunologic↗
PubMed1989

Nonionic block polymer surfactants modulate the humoral immune response against Streptococcus pneumoniae-derived hexasaccharide-protein conjugates.

Nonionic block polymer surfactants (NBPs) were tested for the capacity to stimulate the antibody response against hexasaccharide (HS), derived from Streptococcus pneumoniae type 3 capsular polysaccharide (S3PS), which was conjugated to proteins. The immune response was evaluated in the (CBA/N x BALB/c)F1 progeny, in which female mice are phenotypically normal whereas male mice carry an X-chromosome-linked immunodeficiency. NBPs L101, L121, 1101, and 1501 were able to increase anti-HS immunoglobulin M (IgM) and IgG levels in both normal and X-chromosome-linked immunodeficient mice (with up to 74-fold stimulation of antibody titers). Distribution of S3PS-specific antibodies over the various IgG isotypes was restricted after immunization with either HS-bovine serum albumin or HS-keyhole limpet hemocyanin (HS-KLH). Addition of NBPs (in particular 1501) resulted in a more diverse immune response with either antigen as judged by isotype distribution. Isoelectric focusing of individual sera and subsequent detection of S3PS-binding antibodies in these sera by immunochemical staining revealed a restricted number of different spectrotypes in the course of the immune response. Upon immunization of mice with HS-KLH, spectra of secreted antibodies were slightly more complex and more densely stained than after immunization with HS-bovine serum albumin. Furthermore, NBPs 1101 and 1501 appeared to be able to stimulate the secretion of antibodies, which were secreted only in small amounts without the use of NBPs. Different explanations for increased spectrotype diversity after immunization with KLH as the carrier and after administration of NBPs as the adjuvant are discussed.

Adjuvants, Immunologic↗
PubMed1988

Measurement of the humoral immune response against Streptococcus pneumoniae type 3 capsular polysaccharide and oligosaccharide containing antigens by ELISA and ELISPOT techniques.

A sensitive ELISA has been developed to study immune responses in mice against Streptococcus pneumoniae type 3 capsular polysaccharide (S3PS) and hexasaccharide (HS)-protein conjugates derived therefrom. An advantage of the described system is that the same microtiter plates can be used for both ELISA and ELISPOT tests with a standardized washing procedure and diluent composition. S3PS induced predominantly IgM antibodies and minute amounts of IgG as measured by ELISA in serum. This was accompanied by large numbers (greater than 14000) of IgM spot-forming cells in the spleen. A shift towards IgG production was achieved by addition of lipid A. HS-protein conjugates induced predominantly IgG antibodies after booster immunization(s). Furthermore these conjugates induced large numbers (greater than 40000) of IgG spot-forming cells (SFC) in the spleen. ELISA and ELISPOT assays on microtiter plates are both reliable and highly reproducible assays for the evaluation of immune responses to S. pneumoniae antigens.

Animals↗
PubMed1988

Nonionic block polymer surfactants enhance immunogenicity of pneumococcal hexasaccharide-protein vaccines.

Incorporated in oil-in-water emulsions, nonionic block polymer surfactants change the kinetics of generated antibody responses against pneumococcal hexasaccharide-protein conjugates: prolonged immunoglobulin M and immunoglobulin G responses are realized. Nonionic block polymer surfactants favor the immunogenicity of hexasaccharide-protein conjugates in young mice in such a way that a single injection yields long-lasting protection.

Adjuvants, Immunologic↗
PubMed1988

Stimulation of liposome-induced humoral immune responses by non-ionic block polymer surfactants in Xid mice.

Non-ionic block polymers (NBPs) have proved to be potent adjuvants for the humoral immune response against liposomes haptenated with tripeptide-enlarged dinitrophenyl groups (hapten J). Since both reversed triblocks and normal octablocks displayed adjuvant activity, reversed octablocks, in which structural properties of both groups are combined, were also tested for their adjuvant activity. The latter compounds displayed very strong adjuvant activity for J-haptenated liposomes, not only in normal BALB/c but also in (CBA/N x BALB/c)F1 progeny. To test the applicability of NBPs as adjuvants in semi-synthetic vaccines, the capacity of NBPs to stimulate the immune response against liposomes haptenated with Streptococcus pneumoniae type 3 capsular polysaccharide-derived oligosaccharides was analysed. In these studies, again NBPs proved potent adjuvants, stimulating antibody production to a large extent. In male (CBA/N x BALB/c)F1 mice, which carry a X-chromosome-linked immunodeficiency (Xid), antibody levels were stimulated to the largest extent by a normal octablock. Stimulation of antibody titres, however, did not result in increased protection in these Xid mice.

Adjuvants, Immunologic↗
PubMed1987

Adjuvant effects of nonionic block polymer surfactants on liposome-induced humoral immune response.

The ability of several surface-active agents to stimulate the humoral immune response in mice against haptenated liposomes was tested. The surfactants were block copolymers of hydrophilic polyoxyethylene (POE) and hydrophobic polyoxypropylene (POP) that differed in m.w., percentage of POE, and mode of linkage of POP to POE. The liposomes were haptenated with tripeptide-enlarged dinitrophenyl coupled to phosphatidylethanolamine, which was incorporated into the liposomal membrane. Additional injection of mice with surfactant stimulated serum hemagglutination titers and splenic plaque-forming cell (PFC) numbers to varying extents. Block polymers with POP chains flanking a POE center, as well as polymers with POE chains flanking a POP center, displayed high adjuvant activity. These block polymers stimulated the antibody response in a dose-dependent manner. They stimulated the antibody response with both high and low antigen doses. Furthermore, the addition of one of these adjuvants (25R1) reduced the amount of carrier lipid required in the liposome in order to obtain an optimal antibody response. The surfactants, which displayed high adjuvant activity, did not interfere with liposome stability as measured with a liposome lysis assay. Moreover, in vitro preincubation of liposomes with a block polymer did not affect their immunogenicity. Optimal adjuvant activity was observed when both adjuvant and liposomes were administered by the same route. Simultaneous injection of both components, however, is not a prerequisite. Conclusively, it can be stated that nonionic block polymer surfactants are potent adjuvants for stimulation of the antibody response against haptenated liposomes.

Adjuvants, Immunologic↗
PubMed1987

Synthetic sulpholipopolysaccharides: novel adjuvants for humoral immune responses.

Referring to the strong immunostimulating activity of combinations of lipophilic agents and dextran sulphate, conjugates with chemical determinants of both types of adjuvants were synthesized and then examined for immunostimulatory capabilities in mice. Saturated fatty acids with varying chain lengths and sulphate groups were coupled covalently at defined ratios to the polysaccharide Ficoll (MW 400,000). Chemical analysis of 60 of the sulpholipopolysaccharides synthesized revealed that the number of sulphate groups per monosaccharide unit varied from 0 to 1.6, and the number of lipid groups from 0 to 0.8. Adjuvanticity of these conjugates for the humoral immune response was determined using sheep red blood cells (SRBC) and dinitrophenyl-haptenated bovine serum albumin (DNP-BSA) as antigens. Five days after intraperitoneal injection of adjuvant and antigen, the numbers of direct anti-SRBC plaque-forming cells (PFC) in the spleen were determined. Anti-DNP antibody titres were measured from 1 to 4 weeks after immunization. PFC responses to 2 X 10(6) SRBC were augmented up to a 100-fold by conjugates of Ficoll and sulphate (sulphopolysaccharides: SPs) or lipid groups (lipopolysaccharides: LPs). Introduction of low or moderate numbers of lipid groups in SPs reduced adjuvanticity. Adjuvant activity of sulpholipopolysaccharides (SLPs) with varying sulphate and high lipid content depended on the sulphate contents and the chain length of the lipids. Sulphate reduced adjuvanticity of the SLPs, and the number of sulphate groups required for complete annihilation increased with the chain length of the lipid. LPs and SLPs, including conjugates that did not enhance anti-SRBC PFC responses, augmented serum antibody responses to DNP-BSA while SPs were hardly effective.

Adjuvants, Immunologic↗