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Biomedical subjects

H Nygren

Publications and source records attributed to H Nygren.

At least 73 records · Page 4Linked to original sources
PubMed1985

Relation between components of the immune response in rats sensitized by aerosol and subcutaneous injections.

Relations between the appearance of various components of the immune response were analyzed in two groups of rats sensitized by aerosol and subcutaneous injections in the neck region, respectively. The relations were expressed by Spearman rank correlation coefficient and studied by cluster analysis. In the aerosol-sensitized animals, there was a close association between IgA and IgG antibody levels in bronchial fluid and these in turn were related to IgG levels in serum and more loosely to IgE levels in bronchial fluid. There was an apparent association between IgE antibody formation and mast cell maturation in cultures of regional lymph node cells and the appearance of mucous cells in the lungs. These variables seemed associated with spontaneous cell proliferation in vitro and the numbers of mast cells in the lungs. This indicates that local stimulation with antigen induces local immune responses and immune-mediated migration of cells. In subcutaneously sensitized animals, formation of IgG antibodies in vitro seemed related to the stimulated proliferation of regional lymph node cells. The levels of IgG and IgE antibodies in bronchial fluid and in serum also appeared to be related. Unlike the findings in aerosol-sensitized animals there was no apparent relation between the differentiation of mast cells and mucous cells. This was possibly due to lack of immune-mediated antigen-induced cell migration. The different immune response patterns in aerosol and subcutaneously sensitized rats should be considered when studies are designed aiming to explore the pathogenesis of allergic inflammatory diseases. The findings also indicate that the various parameters of immunity are more closely related in aerosol than in subcutaneously immunized animals.

Aerosols↗
PubMed1984

Solid-phase enzyme-linked immunospot (ELISPOT) assay for enumeration of IgG rheumatoid factor-secreting cells.

Although IgG rheumatoid factor may play an essential role in the pathogenesis of rheumatoid arthritis, there is no precise method for its specific detection at the cellular level. A modification of the recently developed enzyme-linked immunospot assay has been devised for enumeration of cells secreting IgG rheumatoid factor (IgG RF) and simultaneous quantitation of the IgG RF secreted. Specific, sensitive and simple, this new assay should provide a valuable tool for study of isotype-specific RF secretion by single cells.

Animals↗
PubMed1984

Reverse enzyme-linked immunospot assay (RELISPOT) for the detection of cells secreting immunoreactive substances.

A reverse modification of the recently described enzyme-linked immunospot assay (ELISPOT), based on localized enzyme-substrate reactions in gel, is described for the enumeration of antigen-secreting cells using petri dishes coated with specific antibodies. As a model the detection of mouse and human immunoglobulin-secreting cells has been evaluated. Simple and sensitive, this new method, termed RELISPOT, can be adapted for the quantitation of secreted antigen thus providing additional information on the metabolic state of the population of cells tested.

Adult↗
PubMed1984

Covalent coupling of polysaccharides to silicon and silicon rubber surfaces.

A method to produce a hydrogel by covalently coupling dextran polysaccharide to silicon and silicon rubber surfaces is described. A bifunctional epoxysilane was used as coupling mediator and the conditions for the reaction were optimized. Coupling of the silane to silicon rubber was possible only after oxidation of the surface by plasma etching. The reaction between the epoxy-group and dextran was concentration dependent and required high concentrations of dextran. The turnover rate of fibrinogen in solution at the hydrophilic surface was found to be high when measured by ellipsometry.

Adsorption↗
PubMed1984

Bronchial reactivity in relation to immune responses in rats after subcutaneous sensitization without adjuvant.

Rats of BNxWi /Fu strain were immunized by daily subcutaneous (s.c.) injections of antigen without the use of adjuvant for two 2-week periods with a 4-week interval. The bronchial responses to airway and intravenous (i.v.) antigen challenge were measured during and after the immunization period. These responses were compared with both the humoral and the cell-mediated immune response of the animals. Immunization induced bronchial reactivity of the animals to antigen after airway and i.v. challenge. This reactivity persisted for 7 weeks following the second immunization period. Specific IgE antibodies were detected in serum, bronchial fluid and in supernatants from cultured peripheral lymph node cells. The immunization also resulted in an IgG antibody response. Neither the amount of IgE, IgG2a, nor of any other isotype, correlated with the bronchial reactivity in the animals. Antigen stimulation of lymph node cells mixed with syngeneic spleen cells induced proliferation. This procedure also resulted in a maturation of mast cells in 3-week cultures. The immunization also resulted in some increase in the number of mast cells around vessels in the lung. There was no correlation between these parameters of cell-mediated immunity and either antibody responses or bronchial reactivity.

Adjuvants, Immunologic↗
PubMed1984

Degradation of human immunoglobulins by proteases from Streptococcus pneumoniae obtained from various human sources.

The ability of Streptococcus pneumoniae to degrade human secretory immunoglobulin A (S-IgA), IgG, and IgM was tested in 102 strains by use of the thin-layer enzyme assay cultivation technique. The strains were isolated from patients with acute phases of otitis media, meningitis, and pneumonia as well as from symptomless carriers. An ability to degrade S-IgA, IgG, and IgM was revealed in 50, 84, and 96 strains, respectively. An IgG- and IgM-degrading ability of S. pneumoniae has not previously been reported. A concurrent degradation of the three immunoglobulins was revealed in 38 strains; degradation of two of them was revealed in 54 strains, and degradation of only one of them was revealed in 9 strains. One strain failed to degrade any of the immunoglobulins. Correlations were not found between the ability of the S. pneumoniae strains to degrade S-IgA, IgG, or IgM and the serotype affiliation or between the ability to degrade IgG or IgM and the origin of strains. However, the ability to degrade S-IgA was evident more often in strains isolated from symptomless carriers and from bronchial secretions of patients with acute pneumonia than it was in strains from patients with acute meningitis or acute otitis media or from the blood of patients with acute pneumonia. These latter findings may indicate a biological significance of S-IgA-degrading ability in bacterial colonization of mucosal surfaces.

Female↗
PubMed1984

Intestinal resistance to cholera toxin in mouse. Antitoxic antibodies and desensitization of adenylate cyclase.

Mice were immunized perorally with cholera toxin (CT), cholera B-subunit (CB), or buffer as control. The response of anti-CT antibodies of the IgG, IgA and IgM class in bile, IgA being predominating, were similar in both immunized groups. The same number of anti-CT containing plasma cells (ACC) were determined in the intestinal lamina propria of CT - as well as of CB-immunized mice 20 days after the last immunization, while ACC at day 4 in the CB group were 50% higher than in the CT group. In contrast to the vigorous antibody response to CT in both groups of immunized mice, only animals immunized with CT displayed resistance to CT-induced intestinal hypersecretion and to CT stimulation of adenylate cyclase. The CB-treated group responded to CT with fluid accumulation and enzyme activation similar to controls. The results suggest that intestinal resistance to CT in mouse is due to desensitization of adenylate cyclase rather than to CT-neutralizing antibodies.

Adenylyl Cyclases↗
PubMed1984

Development of mucous cells in mouse intrapulmonary airways induced by cholera toxin, dibutyryl cyclic AMP and prostaglandin E1.

The effect of cholera toxin (CT), dibutyryl cyclic adenosinemonophosphate (DE-cAMP) and prostaglandin E1 (PGE1) on the morphological appearance of mouse intrapulmonary airway epithelium has been studied. All three secretagogues, known to mediate their activity via cAMP, induced increased numbers of mucous cells, but with different kinetics. After exposure to DB-cAMP, mucous cells appeared after 7 h with a peak value at 48 h. The corresponding values for PGE1 were 24 h for the appearance and 48 h for peak value whereas exposure to CT gave a lower response with a peak at 72 h. Autoradiography of lungs from mice injected with 3H-thymidine showed that the mucous cells appeared without any foregoing DNA synthesis, however, increased numbers of labelled cells were seen as a late response to the secretagogues.

Adenylyl Cyclases↗
PubMed1984

Protection against experimental cholera in the rat. A study on the formation of antibodies against cholera toxin and desensitization of adenylate cyclase after immunization with cholera toxin.

The importance of antibodies to cholera toxin (CT) versus desensitization of intestinal adenylate cyclase for protection against experimental cholera in the rat was investigated. Animals were immunized five times with CT either perorally or intravenously; antitoxic antibodies were measured in both serum and bile, and intestinal anti-CT-containing plasma cells (ACC) as well as eosinophilic leucocytes were counted. Both peroral and intravenous immunizations induced high levels of serum antibodies, while antibodies in bile appeared only after peroral immunization. The number of eosinophilic leucocytes in the intestinal mucosa increased in response to peroral immunization. CT-induced stimulation of intestinal adenylate cyclase was significantly suppressed, i.e., desensitized, after peroral immunization, but was equally stimulated in intravenous immunized and in control animals. A constant and long-lasting protection against CT-induced secretion was obtained after peroral immunization. This protection correlated neither to the concentrations of antitoxic antibodies in serum, nor to those in bile, nor to the number of ACC, but did correlate to the desensitization of adenylate cyclase.

Adenylyl Cyclases↗
PubMed1984

Mononuclear cells, mast cells and mucous cells as part of the delayed hypersensitivity response to aerosolized antigen in mice.

Mice (BALB/c) exposed to picryl chloride (PiCl) on their shaved abdomen and untreated animals were after 7 days exposed to daily aerosolized trinitrophenylated dog serum albumin (TNP-DSA). Mice exposed to PiCl tended to respond earlier and more strongly with both delayed hypersensitivity (DH) and IgG antibodies in serum and bronchial washings than did mice exposed to aerosol only. Picryl chloride sensitization resulted in spontaneously proliferating axillary lymph node cells, which could not be further stimulated with antigen or mitogen. Histological examination of lung tissue of aerosol-sensitized animals revealed an increase in mononuclear cells and mast cells around bronchioli and mucous cells, particularly in those animals exposed for prolonged periods and sensitized with PiCl prior to aerosol. Sensitization of mice with aerosolized TNP-DSA administrated in two 2- and 1-week periods with a 4-week interval responded with DH and IgG antibody in a dose dependent fashion irrespective of presensitization with PiCl. In bronchial washings IgG antibodies were found particularly after two 2-week periods of exposure. The cells taken from the axillary or brachial lymph nodes showed spontaneous proliferation. Culture of the cells to achieve mast cell maturation resulted in no or very low numbers of mast cells in the lymph nodes.

Aerosols↗
PubMed1983

A solid-phase enzyme-linked immunospot (ELISPOT) assay for enumeration of specific antibody-secreting cells.

A solid-phase enzyme-linked immunosorbent assay (ELISPOT) is described for enumeration of cells secreting specific antibody. Spleen cells from immunized mice are incubated in antigen-coated polystyrene plates. After removal of the cells, bound antibodies are demonstrated by means of an immunoenzyme procedure in which enzyme-substrate reactions are performed in agarose. Dark-brown circular zones (spots), localized in areas of the dish where antibody production has occurred, are enumerated with the naked eye. Spectrophotometric estimation of enzyme-bound activity may be performed by substituting the gel for a liquid buffer, allowing accurate estimation of the total amount of secreted antibody. Versatile, sensitive and very easy to perform, this new assay provides a useful alternative to conventional plaque-forming cell assays.

Animals↗
PubMed1983

Direct visual detection of protein antigen: importance of surface concentration.

A new type of commercially available substrate was used for visualization of antigen binding to antibodies immobilized on the substrate surface. Addition of antigen induced sufficient increase of the protein layer to allow direct visualization, provided that the antibodies immobilized at the surface were immunosorbent isolated. This finding shows the importance of the surface concentration for direct optical visualization of antigen. The results are discussed in relation to previous reports that it is not possible to visualize directly the binding of protein antigen to surface-immobilized antibodies.

Animals↗
PubMed1983

False positive results in class-specific rheumatoid factor (RF) assays due to interaction between RF and Fc fragments of anti-immunoglobulin indicator reagents.

A recently developed, simple immunological method, diffusion-in-gel ELISA, has been adapted for class-specific determination of rheumatoid factor (RF). Evidence was obtained of an analytical error due to interaction between RF and antigenic determinants on the Fc part of the indicator immunoglobulin (Ig) molecules used. This was eliminated by replacing the usual indicator reagent, complete Ig molecules, by conjugated Fab or F(ab')2 fragments. The findings imply that unless the RF-Fc interaction mentioned is avoided in the assaying technique, false positive results may be obtained for, e.g. IgG RF and IgA RF in sera containing IgM RF.

Antibodies, Anti-Idiotypic↗
PubMed1983

Relation between mucous cells and lymphoid tissue in rat intrapulmonary airways.

The distribution of mucous cells in rat intrapulmonary airways was investigated by conventional light microscopic technique. A striking association was found between differentiation of epithelial mucous cells and accumulation of lymphoid tissue in the lamina propria of bronchioli. Nodular accumulations of lymphoid tissue, covered by a lymphoepithelium, as well as differentiation of mucous cells, increased with age. This normal development was accelerated in rats exposed to aerosolized ovalbumin.

Aging↗
PubMed1983

Immune responses in rats sensitized with aerosolized antigen. Antibody formation, lymphoblastic responses and mast cell and mucous cell development related to bronchial reactivity.

Rats of BN X Wi/Fu strain were immunized by aerosol exposure to 0.001-1% of ovalbumin (OA) without using any adjuvant for 2- or 1-week periods with 4-week intervals. The immunization, particularly with the highest dose, induced antibody formation of IgE, measured with RAST, and of IgG and IgA, measured with ELISA. Regional lymph node cells from immunized animals showed spontaneous proliferation which was suppressed by syngeneic spleen cells. The cell mixture could be stimulated by addition of specific antigen or mitogen, while cultures of peripheral lymph node cells showed a less consistent increase in lymphoblast formation. Histological examination of the lungs of immunized animals revealed a rapid onset of inflammation with accumulations of mononuclear cells and also increased numbers of mast cells. There was some dose-response relationship between antigen concentration and cell accumulations. The immunization also seemed to induce differentiation of epithelial cells to mucous cells. Intravenous provocation of animals immunized with 0.01-1% OA aerosol resulted in clinical bronchial reactivity assessed as increased transpulmonary pressure. This airway response was attenuated by pretreatment with indomethacin. Animals immunized with 1% OA did, however, not respond to challenge. These animals showed a decreased response to serotonin compared with nonimmunized controls. In summary, the described animal model seems to provide a tool for studies of the asthmatic reaction.

Aerosols↗
PubMed1983

Induction of humoral immunity and pulmonary mast cells in mice and rats after immunization with aerosolized antigen.

Rats (BN X Wistar) and mice (CBA/Ca) were immunized by exposure in 10-day periods to an aerosol of ovalbumin (OA). In rats this immunization resulted in IgE antibodies detectable at very low levels in bronchial washings, whereas IgG, IgA and IgM antibodies were recorded both in serum and in bronchial washings. In mice, exposure to aerosolized antigen resulted in specific IgE and IgG antibodies in serum. The levels of IgM antibodies were low and no IgA antibodies could be recorded with the enzyme-linked immunosorbent assay (ELISA). Histological examination of lung tissue from immunized rats and mice revealed increased numbers of cells with characteristics of both immature and mature mast cells. In addition, in the rats these cells were more closely located to the bronchi in immunized than in control animals. In the latter animals the mast cells were located around the blood vessels. Immature mast cells were located in the bronchiole-associated lymphatic tissue (BALT) which showed a marked proliferation in immunized animals. The findings indicate that sensitization via the airways provides possibilities to develop a model in rodents for studies of IgE-mediated allergy in the lung.

Aerosols↗