PubMed Health⌕ Search

Biomedical subjects

E C Beuvery

Publications and source records attributed to E C Beuvery.

At least 19 recordsLinked to original sources
PubMed1999

Randomised, controlled trial with the trypsin-modified inactivated poliovirus vaccine: assessment of intestinal immunity with live challenge virus.

The enhanced potency inactivated poliovirus vaccine (E-IPV) was modified to contain trypsin-treated type 3 poliovirus (PV3), strain Saukett, as the type 3 component (TryIPV). This pilot vaccine was previously shown to redistribute the vaccine-induced antibody specificities in mice to mimic those seen in man after poliovirus infection. Groups of infants were then immunised with three doses of TryIPV or E-IPV in a randomised, double-blind trial. Six months after the third dose, at the age of 18 months, the children were challenged with one dose of oral monovalent type 3 poliovirus vaccine. Intestinal immunity was evaluated by assessing the length and extent of PV3 excretion through determination of PV3 titres in 9 successive faecal specimens (2-42 days after challenge). No significant difference in the length or extent of virus excretion was seen between the groups. The results indicate that TryIPV, under the conditions used, was no more potent than the regular E-IPV in inducing resistance to intestinal poliovirus infection.

Antibodies, Viral↗
PubMed1998

In vitro determination of antigen quality: biosensor analysis and fluorescence spectroscopy.

We are probing the potential of two techniques to monitor the quality of antigens in vitro. Structural and conformational differences between diphtheria toxin and toxoid are detected via biosensor analysis (BIA-core) and fluorescence spectrometry. With BIA-core the interaction kinetics between toxin and toxoid and a monoclonal antibody were established. The fluorescence properties of both antigens were determined with respect to fluorescence intensity and emission maximum as a function of guanidinium hydrochloride concentration. In all cases clear differences were found between toxin and toxoid. Antibody affinity of the toxoid was lower compared with toxin, caused by lower binding and higher release rates. Fluorescence intensity of toxoid was reduced by about 50%. Toxoid was less sensitive to guanidinium hydrochloride-induced denaturation, reflected in a diminished shift of the emission maximum.

Animals↗
PubMed1997

A new WHO International Reference Reagent for use in potency assays of inactivated poliomyelitis vaccine.

Assays of the potency of inactivated poliovirus vaccine require the use of an appropriate reference reagent. Preparation 91/574 was shown by international collaborative study to be suitable for determination of antigenic content and immunogenicity of inactivated poliovirus vaccines by in vitro and in vivo assays, respectively. The reagent is a trivalent blend of formaldehyde-inactivated monovalent pools of poliovirus type 1 (Mahoney) poliovirus type 2 (MEF-1) and poliovirus type 3 (Saukett). Studies by antigen-capture ELISA showed that the component monovalent pools contained high titres of D antigen and trace amounts of C antigen. Sucrose gradient analysis showed that the D antigenicity was almost exclusively associated with 150S virus particles. Low levels of procapsids (75S particles with D antigenicity) were detected in the type 1 and 2 monovalent pools. The profile of intact virions and procapsids in 91/574 in sucrose gradients was very similar to PU78-02, a previously used inactivated trivalent poliovirus vaccine reference. The World Health Organization (WHO) Expert Committee on Biological Standardization at its 1994 meeting established preparation 91/574 as the 2nd WHO international Reference Reagent for poliomyelitis vaccine (inactivated). A potency of 430, 95, 285 D antigen units per ml was assigned to poliovirus type 1, 2 and 3, respectively. A separate aliquot of this preparation, established by the European Pharmacopeia Commission as a Biological Reference Preparation, has an identical assigned titre. The 2nd WHO International Reference Reagent 91/574 is intended for calibration of secondary reference reagents.

Animals↗
PubMed1997

Potency of wild-type or sabin trivalent inactivated poliovirus vaccine, by enzyme-linked immunosorbent assay using monoclonal antibiotics specific for each antigenic site.

Potency testing of inactivated poliovirus vaccine (IPV) is hampered by the absence of a standardized in vitro test, as well as the lack of a generally accepted quantitative animal test. In vitro tests must be able to measure selectively the content of the "D" antigen in the vaccine which includes virus neutralizing antibodies. We tested 12 poliovirus type 1, 12 type 2 and six type 3, D antigen-specific monoclonal mouse antibodies (mAb) for use in the enzyme-linked immunosorbent assay (ELISA). We characterized the site-specific reactivities of three mAbs, one for each poliovirus type. The reactivity of the complete mAb panel encompassed the important antigenic sites on the virus surface of each of the poliovirus serotypes. Some of the mAbs were cross-reactive between wild-type and Sabin strain IPV. At least one mAb of each poliovirus type that was D antigen-specific and reacted with both wild-type and Sabin IPV was directed against an antigenic site thought to be immunogenic in humans. These reagents may be useful for improved standardization of the ELISA for IPV.

Animals↗
PubMed1997

Immunogenicity of a pilot inactivated poliovirus vaccine with trypsin-treated type 3-component.

A modified trivalent enhanced potency IPV (E-IPV) containing trypsin-treated PV3/Saukett as the type 3-component (TryIPV) was evaluated in preclinical and Phase I and Phase II clinical trials with the regular E-IPV as a control. In Balb/c mice, TryIPV-induced antibodies targeted outside the trypsin-sensitive antigenic site, as expected. Immunogenicity of TryIPV in man, as judged by a booster response in neutralizing antibodies to type 1, 2 or 3 poliovirus, was as good as that of the regular E-IPV in both adults and children. In children the preimmunization titres of antibodies neutralizing the trypsin-treated PV3/Saukett were significantly lower than those for the untreated virus. Both vaccines induced a striking increase of antibody titres to both virus preparations. No significant harmful effects were observed. We conclude that the pilot vaccine is suitable for further evaluation.

Adult↗
PubMed1997

Inactivated poliovirus vaccine protects transgenic poliovirus receptor mice against type 3 poliovirus challenge.

Transgenic (Tg) mice expressing the human poliovirus receptor (PVR) were vaccinated with inactivated poliovirus vaccine (IPV) and evaluated for induced immunity against type 3 poliomyelitis. One injection of monovalent type 3 IPV elicited protective immunity against wild-type poliovirus. In contrast, 2 injections of trivalent IPV were required for protection. Neutralizing antibody response and protection were vaccine dose-dependent. Administration of polio-immune mouse plasma protected unimmunized mice, demonstrating that neutralizing antibody was sufficient for immunity. IPV heated to remove its D antigen component did not induce protection in Tg PVR mice. IPV derived from a wild-type poliovirus strain gave better protection against wild-type viral challenge than IPV derived from an attenuated poliovirus strain. The newly developed Tg PVR mouse-protection test may be useful in evaluating existing IPV potency tests and for attempts to improve formulations of trivalent IPV or combined vaccines for childhood immunization schedules.

Animals↗
PubMed1996

Single shot with tetanus toxoid in biodegradable microspheres protects mice despite acid-induced denaturation of the antigen.

Tetanus toxoid encapsulated in microspheres consisting of biodegradable polyesters, prepared by four different manufacturers were evaluated with respect to antigenic load, in vitro release pattern, antigen integrity and immunogenicity. In vitro release studies over periods up to 140 days indicated that only during the first days tetanus toxoid was released. Although some preparations were designed to release their antigen content in a pulsatile manner, this was never observed in vitro. A single immunization with 0.3 Lf tetanus toxoid in microspheres induced substantial humoral responses, in most cases higher than one immunization with plain tetanus toxoid, sometimes higher than one dose of alum-adsorbed toxoid but always lower than booster immunizations. It is shown that the moderate (no booster effect) performance of the microsphere preparations is probably due to acid induced denaturation of the antigen. Despite this drawback, protection level in mice after challenge with 50 LD50 1 year after one immunization with microspheres was, on average, substantially higher than mice receiving plain tetanus toxoid.

Acids↗
PubMed1995

Immunogenicity of trypsin treated type 2 and type 3 poliovirus in rats.

Oral polio vaccine will encounter the proteolytic enzyme trypsin during administration but inactivated polio vaccine not. To investigate the effect on the humoral immune response, rats were immunized intramuscularly with trypsin treated type 2 and type 3 poliovirus. IgG and IgM responses were determined as well as the neutralizing antibody titer. It is shown that the immunogenicity of type 2 poliovirus, unlike that of type 3, is hardly affected by trypsin treatment. For type 3, trypsin treatment results in an increase in IgM and neutralizing response. The IgG response decreases after trypsin treatment. The results indicate that IPV formulations may be improved by the addition of trypsin treated type 3, as suggested by Roivainen and Hovi (J Virol 1987; 61: 3749-3753) but not by the addition of trypsin treated type 2 poliovirus.

Animals↗
PubMed1995

Simultaneous administration of oral rhesus-human reassortant tetravalent (RRV-TV) rotavirus vaccine and oral poliovirus vaccine (OPV) in Thai infants.

Rhesus-human reassortant tetravalent (RRV-TV) oral rotavirus vaccine was given at the same time as oral poliovirus vaccine (OPV) or inactivated parenteral poliovirus vaccine (IPV) to Thai infants at 2, 4 and 6 months of age. Sera for rotavirus antibody studies were taken prior to and one month after each vaccination. After the first dose of vaccine at 2 months of age, 37% of the infants receiving rotavirus vaccine with IPV but only 10% of those receiving it with OPV showed a seroconversion by rotavirus IgA ELISA antibody test (p < 0.001). Likewise, neutralizing antibody seroconversion rates in initially seronegative subjects to rhesus rotavirus type 3 (RRV-3) after the first dose of RRV-TV vaccine were higher if the vaccine was given with IPV (74%) than if given with OPV (39%) (p = 0.0069). After the second and third doses of vaccine, the rotavirus IgA ELISA and RRV-3-neutralizing antibody response rates were not different between groups. Development of neutralizing antibodies to human rotavirus serotypes 1, 2 and 4 in the first seven months of life in vaccinees receiving rotavirus vaccine with OPV tended to occur at a lower rate than in those receiving rotavirus vaccine with IPV but the antibody levels were not significantly different at 7 months of age. Poliovirus type 2 and type 3 antibody responses were not different in infants receiving the rotavirus vaccine with OPV as compared with infants receiving only OPV. The mean poliovirus type 1 antibody level was slightly but not significantly lower at 5 and 7 months of age in infants that received both rotavirus vaccine and OPV.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1993

Cultivation of the hybridoma cell line MN12 in a homogeneous continuous culture system: effect of culture age.

The stability of the hybridoma cell line MN12 in a long-term homogeneous continuous culture was studied using a panel of analytical methods. These include two flow cytometry methods, for the determination of relative cytoplasmic and membrane IgG content. In addition, the antibody production was determined by an ELISA, and the metabolic state of the cells was determined by means of glucose consumption and lactate production. These results indicate a possible selection of variants of MN12 hybridoma cells with an overall aerobic metabolism, but with a higher glucose consumption rate and a higher lactate production rate. These variants are mainly characterized by a different membrane IgG content and cytoplasmic antibody content. These changes may possibly be affected by the culture age.

Animals↗
PubMed1992

Analysis of glycoforms present in two mouse IgG2a monoclonal antibody preparations.

Lectins have been used for the determination of the oligosaccharide structures expressed by two monoclonal IgG antibodies, MN12 and RIV6. Dot blot experiments revealed the presence of terminal Fuc alpha (1-->6)GlcNAc, Gal beta (1-->3)GalNAc, Gal beta (1-->4)GlcNAc, Man alpha (1-->6, 1-->3)Man, NeuAc alpha (2-->6)Gal and NeuAc alpha (2-->6)GalNAc on both monoclonal antibodies. MN12 was shown to contain a carbohydrate moiety within the Fc region only. RIV6 contained carbohydrate moieties within both the Fc and Fab regions. Additional O-glycosidic linked carbohydrate chains were detected within the Fc region of both monoclonal antibodies. High mannose structures were also detected on both Mabs.

Animals↗
PubMed1992

Viability measurements of hybridoma cells in suspension cultures.

Several methods were applied to determine the viability of hybridoma cells in suspension. These methods include dye inclusion and exclusion assays such as the classical trypan blue exclusion assay, the propidium iodide (PI) exclusion assay and the fluorescein diacetate (FDA) inclusion assay. Furthermore, the relation was studied between release of lactate dehydrogenase (LDH) by hybridoma cells and their viability. Also the ATP content of the cells and cellular heterogeneity as measured with a flow cytometer were determined in relation to cellular viability. The dye inclusion and exclusion assays using trypan blue, FDA, PI were shown to be useful methods to determine cellular viability. With the FDA and PI methods it was possible to obtain additional information about cells which are in a transition state between viable and non-viable. The viability according to the scatter properties of the cells appears to reflect the overall condition of the cells, although interpretation of the results is difficult. Measurement of LDH release in the culture fluid or the cytoplasmic ATP content could not be used as parameters for cell viability.

Adenosine Triphosphate↗
PubMed1992

The potential of flow cytometric analysis for the characterization of hybridoma cells in suspension cultures.

Flow cytometric (FC) analysis was applied to determine changes at cellular level during the cultivation of hybridoma cell line MN12 in a suspension batch culture. The relative cell size, cytoplasmic and membrane IgG content and the viability were monitored. Besides, the specificity of the cytoplasmic and membrane IgG was ascertained by means of a synthetic peptide containing the antigenic epitope recognized by the antibody. Cell size was found to increase during the exponential growth phase. The viability as determined by FC follows a similar pattern with the viability data obtained by the conventional trypan blue exclusion test. The relative cytoplasmic and membrane IgG contents were high during the exponential growth and low during stationary phase. Measurement of cell cycle distribution and the antibody content in the culture fluid, indicated that the major part of the cytoplasmic IgG is secreted by cells in the G1-phase. It is concluded that flow cytometry is a useful tool to characterize hybridoma cell lines in a suspension batch culture.

Amino Acid Sequence↗
PubMed1992

The influence of sucrose, dextran, and hydroxypropyl-beta-cyclodextrin as lyoprotectants for a freeze-dried mouse IgG2a monoclonal antibody (MN12).

The influence of lyophilization on the stability of a monoclonal antibody (MN12) was investigated. MN12 was freeze-dried in different formulations [without lyoprotectant or in the presence of sucrose, dextran, or hydroxypropyl-beta-cyclodextrin (HP beta CD)] and under varying conditions (with or without secondary drying). Subsequently, the monoclonal antibody was stored for 18 or 32 days at various temperatures (4, 37, or 56 degrees C). For comparison, solutions of MN12 were stored under the same conditions. Regardless of the lyoprotectant used, precipitation and a concomitant reduction of the antigen-binding capacity by about 10% were observed upon reconstitution of lyophilized MN12. HP beta CD proved to be the most effective stabilizer to prevent degradation of lyophilized MN12 during storage. Compared with MN12 solutions, HP beta CD-containing lyophilized MN12 cakes were more resistant to heat-induced charge alterations and loss of antigen-binding capacity.

2-Hydroxypropyl-beta-cyclodextrin↗
PubMed1992

Instability of a hybridoma cell line in a homogeneous continuous perfusion culture system.

In this study several analytical techniques were applied to obtain information about the stability of expression, the yield, and the integrity of a monoclonal antibody (Mab) produced by hybridoma cell line RIV6 in a homogeneous continuous perfusion culture system. The total antibody as well as the isotype-specific antibody contents decreased continuously during the course of cultivation, while the viable cell concentration remained constant. The origin of the discrepancy between the Mab contents observed by two enzyme-linked immuno sorbent assay (ELISA) systems during the steady state was due to fragmentation of the IgG molecule, either cytoplasmic or in the culture fluid, as determined by sodium dodecylsulphate polyacrylamide gel electrophoresis (SDS-PAGE) and western blotting. The IgG-secreting cells as well as the fraction of cells containing a high cytoplasmic IgG content decreased continuously during cultivation. The isoelectric focusing (IEF) pattern showed the appearance of two additional bands after five days of cultivation. This work indicates that cell line RIV6 is unstable in the culture system used, with respect to cell properties and product formation.

Animals↗
PubMed1992

Preparation, antigenicity, and immunogenicity of synthetic ribosylribitol phosphate oligomer-protein conjugates and their potential use for vaccination against Haemophilus influenzae type b disease.

Synthetically prepared ribosylribitol phosphate dimer and trimer analogous to fragments of the capsular polysaccharide of Haemophilus influenzae type b, containing either an amino- or a (masked) thiol-functionalized spacer, were conjugated to protein by two different methods. The thiol-containing carbohydrates were conjugated to tetanus toxoid or H. influenzae outer membrane protein using N-succinimidyl 3-(2-pyridyldithio)propionate. Glutaric dialdehyde was used to conjugate the amino-containing carbohydrates with tetanus toxoid. All conjugates were able to bind antibodies raised against the native bacterial polysaccharide, as determined by competition ELISA. The glutaric dialdehyde conjugate prepared from ribosylribitol phosphate trimer and tetanus toxoid induced a strong polysaccharide-specific antibody response in mice and rabbits.

Animals↗