Biomedical subjects

C Endresen

Publications and source records attributed to C Endresen.

52 records · Page 3Linked to original sources

PubMed1978

Protein A reactivity of whole rabbit IgG and of fragments of rabbit IgG.

Approximately 15 per cent of the total IgG in normal rabbit serum reacted with protein A. When this protein reactive IgG fraction was treated with acid at pH 2.7 and then digested with plasmin, thus splitting the rabbit IgG between the CH2 and CH3 domains, both the isolated Facb and the pFc' fragments were protein A non-reactive. This results indicates that at least one intact Fc chain is necessary to fulfil the protein A-fc interaction. Traces of protein A reactive rabbit F(ab')2 fragments isolated from normal IgG were also found. These fragments mixed with normal rabbit IgG precipitated protein A.

Animals↗

PubMed1977

Immunochemical characteristics of subfragments from the CH3 homology region of human IgG.

A subfragment (peak IV) of Fc from human IgG belonging to the CH3 region and found to be slightly different from both pFc and tFc' fragments was released after tryptic digestion of acid-treated Fc. Gel filtration at dissociating conditions of reduced and alkylated fragments indicated a molecular weight of 10,200. The Fc, pFc', tFc', and peak IV fragments all interacted with a rheumatoid factor having anti-Gm(1) specificity and showed a reaction of identity in agar diffusion against both anti-Fc and anti-pFc' sera. In immunoelectrophoresis, peak IV and tFc' fragments behaved similarly but with a more anodical movement than pFc' fragments. The probable location of the new fragment in terms of the sequenced gamma1-chain is proposed to be the residues 335 to 439.

Amino Acid Sequence↗

PubMed1976

Human agglutinins to rabbit erythrocytes. Characterization of an antigen.

Crude preparations inhibiting the agglutination of rabbit erythrocytes by pooled human serum were obtained by extraction of erythrocyte stromata with various solvents (chloroform/methanol, trichloroacetic acid, and so forth). Highest inhibiting activity was found in a preparation containing sphingoglycolipid; 0.8 mug inhibited 2 agglutinating units of serum. The active preparations retained their activity after 5 min of incubation in a boiling water bath and after treatment with proteolytic enzymes or neuraminidase. Treatment with periodate abolished the activity. The antigenic site is therefore probably determined by the sugars of the sphingoglycolipid.

Agglutination Tests↗

PubMed1976

An examination of the "star-phenomenon", a three component immunoprecipitation involving staphylococcal protein A.

The co-precipitation called "star-phenomenon" occurred between the three component system: protein A, an IgG forming soluble complexes with protein A and F (ab')2-preparations of human IgG, guinea pig IgG or rabbit anti-staphylococcal IgG. Co-precipitation also occurred if the IgG was replaced by normal human Fc fragments. On a protein A column the human F (ab')2-preparation was separated into a major non-reactive and a minor reactive fraction. Only the latter contained Fc-structures, these being isolated on an anti-Fc column and found to belong to undigested IgG. The "star"-forming protein A reactive F (ab')2-fragments were washed through the anti-Fc column. The F (ab')2 fraction from rabbit anti-staphylococcal IgG contained no Fc-structures and only a small portion containing anti-protein A activity was active in co-precipitation.

Animals↗

PubMed1976

Further characterization of protein A reactive and non-reactive subfragments of Fc from human IgG.

Tryptic digests of acid-treated Fc from normal human IgG were separated into four peaks (I-IV) by gel filtration on Sephadex G-100. The second peak was further divided into two fractions (II and II'). Peak I was indistinguishable from intact Fc on electrophoresis, immunodiffusion, and reactivity to protein A. The protein A reactive fragments of fractions II, II', and III were shown to contain antigenic determinants of both the CH2 and CH3 domains, to interact with the anti-Gm (1) specific rheumatoid factor, and to fix complement. These results, together with SDS-electrophoresis, showed that protein A reactive fragments are all composed of an intact Fc chain with shorter chains covalently linked to it. The protein A non-reactive fragments of fractions II' and III were homogeneous, fixed complement and showed no interaction with the Gm (1) rheumatoid factor. These results, in addition to the observed antigenic determinants, localized the fragments to the CH2 region.

Bacterial Proteins↗

PubMed1976

Immunochemical analysis of an unusual cell wall polysaccharide from animal coagulase-positive staphylococci. 1. Fragments obtained after hydrolysis in hydrofluoric acid and alkali.

Polysaccharide P (poly P) of canine coagulase-positive staphylococci contains glycerol, glucose, glucosamine, muramic acid, phosphate, and the usual peptidoglycan amino acids, but does not cross-react serologically with standard teichoic acids. Products from hydrolyses in hydrofluoric acid and alkali contained phosphates of glycerol and glucose as well as combinations of these, but neither glucosyl-glycerol units nor glucosamine-phosphates were observed. The teichoic acid of poly P is probably a polymer of a repeating unit consisting of alternating glycerol, phosphate and glucose.

Alkalies↗

PubMed1976

Immunochemical analysis of an unusual cell wall polysaccharide from animal coagulase-positive staphylococci. 2. Probable structure based on chemical and serological studies.

The teichoic acid of polysaccharide P (poly P) contains glycerol, glucose and phosphate. Hydrofluoric acid and alkali hydrolysates contain glycerol 1-phosphate, glycerol diphosphate, and glucose 1-phosphate, but no glucosyl-glycerol fragments. Glucose and the serological activity of poly P were destroyed by periodate oxidation. Interaction with concanavalin A showed that the glucose is in alpha-configuration and that the hydroxyl groups at positions 3, 4 and 6 are unsubstituted. Most probably, the poly P teichoic acid is a polymer containing a repeating unit in which glycerol 1-phosphate is attached to the 2-position on alpha-D-glucose 1-phosphate.

Alkalies↗

PubMed1976

Fragments of immunoglobulins in human faeces.

Fab-fragments of IgG were easily demonstrated in extracts of faeces from healthy infants and children. Employing immunoelectrophoresis with antisera to whole human serum and to Fab-fragments of IgG, a marked precipitation line, likely to represent such fragments, was evident in the cathodal or gamma-region. Usually no precipitate was formed with antisera specific for gamma-heavy chains or Fc-fragments of IgG. Presumably IgG in the gut is partially destroyed before being excreted with faeces. Results of immunoelectrophoresis, gel filtration as well as polyacrylamide gel electrophoresis, using antisera to alpha-heavy chains, indicated the presence of fragments of IgA in some faecal extracts. Fragments of IgA could not be demonstrated in IgA-deficient patients, and no fragments of either class, or only traces of Fab-fragments of IgG, were found in agammaglobulinaemic patients. No antibody activity against rabbit erythrocytes was found in gel filtrations containing such fragments; any reaction was not observed either in the direct agglutination test or in a modified antiglobulin test.

Agammaglobulinemia↗

PubMed1975

Fc receptors in human placenta.

Cryostat sections of placental tissue strongly adsorbed erythrocytes sensitized with IgG antibodies of human, rabbit, and guinea pig origin. No adsorption occurred using erythrocytes sensitized with F(ab')2 fragments. The reaction was strongly inhibited by intact IgG and by Fc fragments, weakly inhibited by pFc' fragments, and not inhibited by Facb and F(ab')2 or albumin. These properties are similar to those of corresponding receptors in normal lymphoid tissues. Results obtained with sections of hydatidiform mole showed that the reaction occurred with the trophoblastic tissue. Porcine placenta had no Fc receptor activity. The presence of an Fc receptor in human placental tissue may therefore be of significance for the selective transfer of IgG from mother to foetus.

Animals↗

PubMed1975

Studies on polysaccharide C of Staphylococcus epidermidis. 1. Isolation and chemical characterization.

Polysaccharide C (poly C) has been isolated from two strains of S. epidermidis and characterized chemically. The results suggest that poly C is a wall N-acetylglucosaminylglycerol teichoic acid, linked through 1:3-phosphodiester linkages. One poly C preparation contained only beta-linked N-acetyglucosamine, the other traces of alpha-linked sugar in addition. The degree of substitution of sugar in the poly C preparations from the two strains was about 50 and 25 per cent.

Acetylglucosamine↗

PubMed1974