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Biomedical subjects

G Stålenheim

Publications and source records attributed to G Stålenheim.

9 recordsLinked to original sources
PubMed1979

Effects of serum and cations on the selective release of granular proteins from human netrophils during phagocytosis.

The extracellular release from human neutrophils of the primary (azurophil) granule constituents, myeloperoxidase (MPO), chymotrypsin-like cationic protein (CCP), collagenase and lysozyme, and the secondary (specific) granule constituents, lactoferrin and lysozyme, was measured during ingestion of staphylococcus protein-A-IgG complexes. In buffer, lactoferrin release was consistently higher than that of the other protein. In serum, lactoferrin release increased concomitantly with ingestion, whereas the rate of lysozyme and especially of MPO release were stimulated to a higher degree than ingestion. Magnesium (0.5--2 mM) was more potent than calcium (0.5--2 mM) in promoting release but these cations worked synergistically. Zinc (0.5--4 mM) was found to be a potent and selective inhibitor of collagenase release. Manganese (0.25--4 mM), which inhibited the ingestion of SpA-IgG complexes, also inhibited release of CCP, collagenase, lysozyme and MPO, but actually stimulated lactoferrin release. The data suggests that lactoferrin and lysozyme may be confined to distinct granule populations or else released in a different fashion from the granules. When the effects on release of primary granule proteins are concerned it is suggested that the dissociation of binding of various agents to an anionic granule matrix may be affected differently by various cations.

Blood↗
PubMed1979

Kinetics of the agglutination of IgG-coated latex particles by C1q: the influence of heat-labile serum components.

Interaction between human C1q and IgG coated latex particles has been studied by means of a standard aggregometer equipment. A dose-dependent agglutination was observed and 100 ng of C1q were readily detected. The kinetics of the agglutination was also monitored. Serum, partially purified C1, and high molecular weight fractions from Sephadex G-200 fractionated serum produced agglutination only in the presence of EDTA. In the absence of this chelator these products disintegrated preformed C1q-IgG-latex particle agglutinates. This disagglutinating principle is heat-sensitive and tentatively macromolecular C1 dependent. The most probable basis of the activity is the competition between C1, with a high affinity for IgG particles, and C1q. The inability of C1 to induce particle agglutination might be caused by the C1 subunits C1r and C1s sterically inhibiting the subunit C1q to bridge between the particles.

Agglutination↗
PubMed1978

Opsonins in human serum for the phagocytosis of complexes between IgG and protein A of Staphylococcus aureus.

The phagocytosis of complexes between staphylococcal protein A and 125I-labelled IgG is enhanced by fresh human serum and to a somewhat lesser extent by heat-inactivated serum. Opsonizing activity is detected in two distinct peaks by Sephadex G-200 column chromatography. One peak corresponds to the excluded material and the other to the ascending limb of the second protein peak. The active material in serum is retained on a protein A-Sepharose but not on an IgG-Sepharose column. Active material eluted from a protein A-Sepharose column and run on a Sephadex G-200 column again shows two activity peaks corresponding to those obtained on chromatography of whole serum. The first peak contains mainly IgA nd IgM but very little total protein material. The second peak contains mainly IgG but also IgA. Purified normal IgA, but not one myeloma IgA preparation tested, has the capacity to enhance phagocytosis of protein A-IgG complexes. Possible examinations for the opsonin activity are discussed.

Chromatography, Gel↗
PubMed1977

Enhancement by a serum factor of immunoglobulin-mediated histamine release from human leukocytes.

When serum was fractionated on Sephadex G-200, the material eluted in the second and thir major peaks had a very pronounced capacity to enhance IgE- as well as IgG-mediated histamine release from the leukocytes of both normal and allergic donors. Unseparated serum on the other hand had a low capacity to stimulate anti-IgE-induced histamine release. Besides resulting in a higher histamine release, pretreatment with serum fractions also increased the rate of histamine release. Further purification revealed that the stimulating activity of the material in the second peak was mediated by a trypsin-sensitive component, probably active in low concentration.

Animals↗
PubMed1977

Histamine release from human leucocytes. A serum factor necessary for the induction of histamine release and desensitization by protein A.

The ability of human leucocytes to release histamine on protein A treatment is lost when the cells are washed repeatedly. It is, however, possible to restore the sensitivity to protein A treatment by incubating the leucocytes in serum. Treatment of the cells with purified IgG does not restore the activity. The material responsible for the resensitization is eluted both in the second and the third protein peak when serum is chromatographed on Sephadex G-200, indicating the possible existence of several active factors. Material with low immunoglobulin content, but with retained capacity to resensitize leucocytes to release histamine on protein A treatment, was obtained by repeated chromatography of peak III material on the Sephadex G-200 column. Furthermore, material from the second and third peaks from Sephadex G-200 deprived of their IgG by passage through a protein A Sepharose or a DEAE-cellulose column had the same capacity to resensitize the leucocytes as unseparated material. When serum was separated by Pevikon block electrophoresis, most of the activity was detected in the alpha and beta regions but only little in the gamma region. The serum fractionations indicate that neither IgG nor the other immunoglobulins are the factor(s) responsible for resensitizing the leucocytes to release histamine on protein A treatment. Beside being necessary for protein A-induced histamine release, the factor (or factors) is also essential for protein A-induced desensitization of human leucocytes.

Bacterial Proteins↗
PubMed1976

Quatification of phagocytosis by human neutrophils. The use of radiolabelled staphylococcal protein A-IgG complexes.

Human polymorphonuclear leucocytes suspended in a serum-free medium ingest radiolabelled insoluble staphylococcal protein A-IgG complexes, providing a quantitative measure of phagocytosis. The degree of uptake of protein A-IgG complexes is dependent on the cell concentration, the amount of immune precipitates and duration of incubation. The rate of phagocytosis is enhanced by the presence of serum. During the process of ingestion of immune precipitates, release of the lysosomal enzyme myeloperoxidase but not of the cytoplasmic enzyme lactic dehydrogenase occurs.

Antigen-Antibody Complex↗
PubMed1975

Induction of histamine release and densensitization in human leukocytes.

Protein A from Staphylococcus aureus has been found to react with all human leukocyte preparations tested. In 70 percent of the experiments the reaction leads to histamine release. Furthermore, protein A treatment of cells at 37 degrees C, both in complete and Ca-2+-free medium, results in the inhibition of anti-IgE-induced histamine release in all cell preparations, indicating that protein A and anti-IgE antibodies release histamine from the same cells. This inhibition seems to be due to the blocking or exhaustion of a step in the biochemical pathway, leading to histamine release activated by both protein A and anti-IgE. In some cell preparations desensitization but no histamine liberation is induced by protein A. No inhibition occurs if the protein A treatment is performed at 4 degrees C. It is concluded that protein A elicits histamine liberation and desensitization by acting on IgG present on the surface of the basophil granulocytes. Treatment of leukocytes at 37 degrees C with anti-IgE antibodies, or F(ab)2 fragments from such antibodies, also results in an inhibition of a subsequent anti-IgE-induced histamine release. Desensitization with low doses of anti-IgE results in an inhibition of the same type as that obtained with protein A. Supraoptimum amounts of anti-IgE or high amounts of monovalent Fab fragments from anti-IgE immunoglobulin G give an inhibition that could be due to a competition between the sensitizing and the challenging agents for combining with cell fixed IgE molecules. This inhibition is independent of temperature and calcium concentration.

Animals↗
PubMed1975

Induction of histamine release and desensitization in human leukocytes. Effect of anaphylatoxin.

Hog anaphylatoxin (AT) in concentrations from 0.5 to 5 mug/ml gives a dose-dependent histamine release from human leukocytes. Concentration of 100 mug/ml AT give the same high histamine release as 5 mug/ml. This is in contrast to the histamine release obtained with anti-IgE or allergen, which give low histamine release with high doses. The histamine release obtained with AT is completed in 20 sec and the reaction is temperature- and calcium-dependent. Treatment of cells with AT in the presence or absence of calcium makes them insensitive to another challenge with AT. Such treated cells are fully responsive, however, to challenge with anti-IgE if the pretreatment has been performed in the absence of calcium. This, together with the calcium- and temperature-dependence indicates that the AT-induced histamine release is nontoxic. Treatment of cells with AT in the presence of calcium induces, besides histamine release, decrease in sensitivity to anti-IgE, indicating that both AT and anti-IgE release histamine from the same cells. We discuss to what extent AT and cell-bound Ig share intracellular mechanisms for induction of histamine release.

Anaphylaxis↗