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Biomedical subjects

H Nygren

Publications and source records attributed to H Nygren.

At least 91 records · Page 5Linked to original sources
PubMed1982

Evaluation of solubilized herpes simplex virus membrane antigens in diffusion in gel-enzyme-linked immunosorbent assay (DIG-ELISA).

Cell membranes were prepared from herpes simplex virus (HSV) type 1-infected cells and solubilized with a low concentration of sodium deoxycholate. The supernatant after ultracentrifugation was used as antigen in a newly developed solid phase assay, diffusion in gel-enzyme-linked immunosorbent assay (DIG-ELISA). Antigen solubilization was almost complete, all HSV glycoproteins were represented, the yield of antigen in the solubilization process was high, and the presence of a detergent, sodium deoxycholate, did not interfere with the adsorption of antigen to the solid phase. DIG-ELISA was compared with the neutralization test for the determination of HSC antibodies and zone diameters showed a good correlation with the titre obtained by the neutralization test.

Animals↗
PubMed1982

An electron microscopic study of surface polysaccharides in Bacteroides.

The electron microscopic appearance of the cell surface of Bacteroides strains and Klebsiella pneumoniae stained with ruthenium red or colloidal iron is described. The effect of polymyxin B (PMB) was also registered. It was found that all Bacteroides strains have a polysaccharide lined 'micro-capsule' external to the outer membrane which could aggregate and form blebs. The blebs so formed were distinct from other types of bleb formed in Klebsiella involving the outer membrane and induced by PMB. Such types of PMB alterations were not induced in Bacteroides.

Bacteroides↗
PubMed1982

Diffusion-in-gel enzyme-linked immunosorbent assay (DIG-ELISA). Quantification of antigen by diffusion over an antibody-coated surface.

The diffusion-in-gel enzyme-linked immunosorbent assay (DIG-ELISA) has previously been used for quantification of antibodies. In the present study, using bovine serum albumin as antigen and a corresponding rabbit antiserum as antibody source, the DIG-ELISA principle was used for quantification of antigen. Antibodies were immobilized on a plastic surface, over which the antigen was allowed to diffuse in an agarose gel. The antigen-antibody reaction zones were then detected by binding of an enzyme-labelled antibody directed against the antigen. The enzyme-substrate reaction, yielding a coloured reaction product, was visualized in a substrate-containing gel. The density and quality of immobilized antibody on the surface was found to be critical. Reproducible results were obtained only when antibodies purified with affinity chromatography on immobilized antigen were used. After 46 h of diffusion the diameter of the reaction zones was directly proportional to the logarithm of the antigen concentration in the range 0.4 mg/1-1 g/1. The variability of the method (CV) was 3%.

Animals↗
PubMed1981

Complement-dependent histamine release from rat peritoneal mast cells, induced by lipopolysaccharides from Bacteroides oralis, Fusobacterium nucleatum and Veillonella parvula.

The capacity of phenol/water extracted lipopolysaccharides (LPS) from Bacteroides, Fusobacterium and Veillonella to induce histamine release from rat peritoneal mast cells has been evaluated by means of a bioassay using atropinized guinea pig ileum and a fluorescence assay. Histamine release was found to be completely complement dependent. It was also found that LPS of Veillonella have the greatest capacity to induce histamine release and Bacteroides have the weakest.

Animals↗
PubMed1981

Diffusion-in-gel enzyme linked immunosorbent assay (DIG-ELISA) for detection of antibodies to Yersinia enterocolitica O:3.

The Diffusion-In-Gel Enzyme Linked Immunosorbent Assay (DIG-ELISA) is a new and simple method for the quantitation of antibodies to diffuse from wells in gel in petri dishes and absorb to an antigen coated to the plastic surface prior to testing. The antigen-antibody reaction is visualized with horseradish-peroxidase conjugated class-specific anti-immunoglobulins. The DIG-ELISA permits detection of 0.1 microns/ml of specific antibodies. This method was used to determine the IgG, IgA and IgM antibody levels to Yersinia enterocolitica O:3 in sera from patients with antibody titres to this microorganism, as determined by direct agglutination and complement-fixation test. The DIG-ELISA IgG antibody values, in contrast to IgA and IgM, correlated well to titres obtained by the direct agglutination method. Low degrees of correlations were found for all three immunoglobulin classes when compared to the complement fixation test.

Antibodies, Bacterial↗
PubMed1981

Conjugation of horseradish peroxidase to staphylococcal protein A with benzoquinone, glutaraldehyde, or periodate as cross-linking reagents.

Horseradish peroxidase was conjugated to Staphylococcal protein A by three different two-step procedures using an increasing excess of peroxidase in the second step reaction. The yield of conjugated protein A was analyzed by SDS-polyacrylamide gel electrophoresis. Conjugation of peroxidase to protein A with benzoquinone or glutaraldehyde as cross-linking reagents at a 3- to 4-fold molar excess of peroxidase resulted in a high yield of coupled protein A with conjugates of low molecular size. Conjugation of peroxidase to protein A by the periodate method resulted in a high yield of coupled protein A with polymeric conjugates of large molecular size. Based on these results, conjugates produced with glutaraldehyde as cross-linking reagents were further analyzed. The capacity of the conjugates to precipitate human immunoglobulin evaluated by radial immunodiffusion was found to be reduced to about 50% of that of native protein A. Conjugates produced with glutaraldehyde as cross-linking reagent retained 70% of the enzyme activity of native peroxidase.

Aldehydes↗
PubMed1980

Diffusion-in-gel enzyme-linked immunosorbent assay (DIG-ELISA): optimal conditions for quantitation of antibodies.

In the diffusion-in-gel enzyme-linked immunosorbent assay (DIG-ELISA) the quantitation of antibodies is based on their ability to form a diffusion gradient over an antigen-coated polystyrene surface. The antigen-antibody reaction is then visualized by an enzyme-conjugated anti-immunoglobulin. The enzyme-substrate reaction is finally performed by pouring a substrate-containing gel over the polystyrene surface. In this study with bovine serum albumin as antigen and a corresponding rabbit antiserum, the diffusion time of antiserum was shown to be the most critical variable of the method, while the antigen concentration used for coating, the conjugate binding time and the enzyme-substrate reaction time had a minor influence on the quantitation of antibodies. High antibody levels were measured with greater accuracy than low levels, but the standard deviation was below 10%. It was also shown that different sera containing antibodies to Salmonella typhi O LPS, Klebsiella pneumoniae K1 and O4 LPS, Escherichia coli O2 LPS, Yersinia enterocolitica Y3 LPS, cardiolipin and pneumococcus could be quantitated with the same accuracy.

Animals↗
PubMed1980

Antitoxic cholera immunity in mice: influence of antigen deposition on antitoxin-containing cells and protective immunity in different parts of the intestine.

The importance of the mode of antigen presentation (intravenous, oral, or enteral restricted to the lower ileum) in the development of a local immune response and immunological memory for such a response in different parts of the intestine was studied in mice. Cholera toxin was used as antigen and the immune response was assayed by determining both the number of specific antitoxin-containing cells in the lamina propria and protection against experimental cholera. The results showed that all of these routes of antigen presentation could induce significant memory along the entire small intestine. In contrast, the actual production of antitoxin-containing cells or protective immune response elicited by booster immunization was restricted to those parts of the intestine that were directly exposed to antigen; i.e., lower ileum boosting resulted in immunity in the distal ileum but not in the proximal jejunum, whereas oral or intravenous boosting gave a response in both jejunum and ileum. Protection correlated closely with the number of antitoxin-containing cells in the lamina propria (correlation coefficient, 0.88); >/=4,000 antitoxin-containing cells per mm(3) conferred solid immunity to cholera toxin-induced diarrhea. The total number of immunoglobulin-containing cells in intestines was not significantly influenced by the specific immunizations. There were four times as many of these cells in the upper jejunum (167,000 cells per mm(3)) as in the lower ileum, but the proportions of immunoglobulin A-containing cells (80 to 85%), immunoglobulin M-containing cells (14 to 20%), and immunoglobulin G-containing cells (0.4 to 0.9%) were similar in various parts of the intestine. The results indicate a differential dependence on local tissue antigen for the intestinal antibody-secreting cells and their memory cell precursors.

Animals↗
PubMed1980

Comparison of diffusion-in-gel enzyme-linked immunosorbent assay with conventional serological methods for detection of class-specific antibodies to Salmonella typhi O antigen.

The diffusion-in-gel enzyme-linked immunosorbent assay (DIG-ELISA) is a new and simple method for quantitation of antibodies, based on the ability of antibodies to diffuse from wells in gel and adsorb to antigen which is bound to a polystyrene surface. The antigen-antibody reaction is visualized with a color reaction caused by horseradish peroxidase-conjugated class-specific anti-immunoglobins. This method was used to study the immunoglobulin G, A, and M immune response to Salmonella typhi O antigen in individuals immunized with a monovalent heat-inactivated typhoid vaccine. The antibody values obtained by the DIG-ELISA method correlated with those evaluated by conventional direct agglutination (Widal) and indirect hemagglutination methods. The DIG-ELISA method was also found to be sensitive, specific, and economical, as well as suitable for handling large numbers of sera while requiring very simple equipment.

Antibodies, Bacterial↗
PubMed1980

Effect of the properties of enzyme-antibody conjugates on the quantitation of serum antibodies to Escherichia coli 02 antigen by the enzyme-linked immunosorbent assay, Elisa.

Immunoglobulins conjugated to horseradish peroxidase (HRP) or to alkaline phosphatase (AP) were compared for determinations of antibodies to Escherichia coli 02 antigen using the enzyme-linked immunosorbent assay (Elisa). AP-IgG conjugates had a higher avidity for their antigen than HRP-IgG conjugates. The avidity of AP-IgG conjugates was higher than that of the native IgG fraction from which it was derived, whereas HRP-IgG conjugates had the same avidity as the native IgG fraction. The Elisa method was more sensitive when performed with AP-IgG conjugates. However, differences in antibody titer between sera from convalescent and acutely ill patients with urinary tract infection caused by E. coli were detected with a higher degree of accuracy with the Elisa-HRP method than with the Elisa-AP method. The differences between Elisa-AP and Elisa-HRP are discussed in relation to the qualities of the conjugates.

Absorption↗
PubMed1979

Cathepsin D: ultra-immunohistochemical localization in dentinogenesis.

Cathepsin D was purified from rat liver using a new affinity chromatographic method, based on the coupling to the specific inhibitor pepstatin. This preparation was used for the production of specific antibodies from rabbit. The purified IgG fraction was conjugated to horseradish peroxidase in a two-step coupling procedure and used for electron microscopic immunohistochemistry of the odontoblast-predentine region of the rat incisor. Precipitates, indicating the presence of cathepsin D, were seen in the odontoblast, odontoblast process, and in the extracellular unmineralized matrix, the predentine. The observations are discussed in relation to proteoglycan degradation at the mineralization front simultaneous with crystal formation, and in relation to the function of lysosomal enzymes in the turnover of connective tissue.

Animals↗