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Biomedical subjects

H Vik

Publications and source records attributed to H Vik.

46 records · Page 3Linked to original sources
PubMed1986

Comparative studies on tree pollen allergens. X. Further purification and N-terminal amino acid sequence analyses of the major allergen of birch pollen (Betula verrucosa).

The previously isolated major allergen of birch pollen (fraction BV45), Int. Archs Allergy appl. Immun. 68: 70-78 (1982), was further purified by recycling chromatography. The purified preparation was run on a high-performance liquid chromatography (HPLC) TSK-G-2000 gel filtration chromatography column and, finally, on paper high-volt electrophoresis. The protein recovered met the homogeneity criteria required for performing the N-terminal sequence analysis. The allergenic and antigenic reactivities of the HPLC-purified protein, designated BV45B, was examined. A single homogeneous precipitation line in crossed immunoelectrophoresis (CIE) was shown. Specific IgE-inhibition tests and immuno-autoradiographic prints indicated that this allergen could bind reaginic IgE specificially and with good affinity. The homogeneity of BV45B was examined by isoelectric focusing (IEF). Several minor bands of pI differences of less than 0.1 units were visible, demonstrating the existence of some molecular variants of this protein. The N-terminal sequence analysis of the molecule was performed, and the following four amino acids were tentatively shown by sequential cleavage: NH2-Ala-Gly-Ile-Val-. The demonstration of one dominant N-terminal 1-dimethyl-amino-5-naphthalene sulphonyl (DNS)-amino acid by polyamide thin-layer chromatography at each sequence step confirmed that the N-terminal residue of the protein was not blocked; the heterogeneity shown by the IEF system was merely due to the presence of several homologous polymorphic proteins with identical N-terminal amino acid, the adequacy of the purification repertoire used.

Absorption↗
PubMed1984

Comparative studies on tree pollen allergens. VII. Monomethoxy polyethylene glycol conjugation of the major allergen of birch pollen (Betula verrucosa).

The major allergen of birch pollen (BV45) was conjugated to 2-0-methoxy polyethylene glycol-4,6-dichloro-5-triazine (mPEG). Three molecular weight variants of 4,000, 6,000 and 20,000 daltons, respectively, of the activated PEG were used. The modified preparations were labelled by 125I and both the native and the radiolabelled protein conjugates were purified by gel filtration chromatography. The relative molecular weights of the purified two peaks were preliminarily estimated by high performance liquid chromatography (two populations of greater than or equal to 100,000 or 20,000 daltons). The amino acid composition of the acid hydrolysates of the three conjugated proteins indicated that 5 residues of lysine were modified by mPEG. Other charged amino acid side chains could also be bound to the activated PEG. The immunochemical properties of the copolymers were studied. The immunogenicity and antigenicity were examined by immunizing rabbits with 125I-mPEG 4,000 daltons BV45 and 125I-mPEG 20,000 daltons BV45 and subsequently crossed immunoelectrophoresis. The clearence of the radiolabelled protein showed normal pattern. A sharp decline in the radioactivity could be measured. At days 10-12, the remaining radioactivity was below 2%. Preliminary studies showed that the modified proteins were immunogenic in rabbits. The findings were demonstrated by crossed immunoelectrophoresis of the 125I-mPEG 4,000, 6,000 or 20,000 daltons BV45 and the corresponding autoradiographs. Apparently, the immunogenicity and antigenicity of the preparations were qualitatively unaltered. The allergenicity of the modified preparation was measured in vitro by RAST and RAST inhibition.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1983

Comparative studies on tree-pollen allergens. V. Immunochemical mapping of the antigens and allergens of birch pollen extract (Betula verrucosa).

A comparative electrophoretic and autoradiographic analysis of the different fractions of birch pollen crude extract was performed. This extract included a minimum of 17 reproducible and distinct antigens located in the gel filtration fractions BV2-BV4. Only one of these precipitates had the ability to bind IgE, as demonstrated by immunoelectrophoretic and autoradiographic techniques using several poly- and monospecific rabbit antibodies. The allergenicity of the different fractions was examined in vitro by RAST and RAST inhibition, and in vivo by passive cutaneous transfer and skin prick tests. The data suggested that Betula verrucosa pollen extract contains a group of isoallergens with related antigenicity but with variable molecular sizes. The findings have also confirmed the presence of identical antigenic properties of the previously isolated pI 5.18 and BV45 as deduced from their immunoelectrophoretic and autoradiographic studies.

Allergens↗
PubMed1983

Comparative studies on tree-pollen allergens. VI. The effect of thermal denaturation on the reactivity of birch pollen (Betula verrucosa) allergens.

The structural changes as due to thermal denaturation of antigens and allergens of birch pollen produced by gel filtration chromatography were studied by circular dichroism, RAST inhibition and immunoelectrophoretic techniques. Results of circular dichroism showed that both BV3 and BV4 contained 20-25% alfa-helix, while BV45 consists of beta-pleated sheet and random coil. Fractions BV3 and BV4 lost about 50% of their native tertiary structures when heated at 100 degrees C for 3 h. The number of antigenic lines found in the CIE plates for the heat-treated fractions was reduced as well. The CRIE preparations showed unchanged radiostaining for the heated BV3 fraction (correlated to the untreated BV3 fraction). For the BV4 fraction a diminished radiostaining was observed. A reduction of 8-fold and 4-fold of the IgE binding capacity was observed in RAST inhibition for fractions BV3 and BV4, respectively after heating. The purified fraction BV45 showed 50% decrease in CD absorption after heating to 100 degrees C for 1 h. The CIE pattern of the heated fraction gave a single precipitate line and the area under the precipitate line was reduced as compared to the unheated fraction. The CRIE plate showed reduced intensity of radiostaining. Skin prick tests and PK tests confirmed the reduced allergenicity of the heated fractions. These findings confirm the relative thermostability of the allergens in birch pollen. However, heating infers irreversible changes on the tertiary structure of the molecules, and these structural changes can be correlated to a quantitative reduction of allergenic reactivity.

Animals↗
PubMed1982

Comparative studies on tree pollen allergens. IV. Evaluation of two commercially available allergen extracts of alder (Alnus incana) and birch (Betula verrucosa) pollen.

Two commercially available extracts of alder and birch pollen usually used in clinical allergy were evaluated and correlated to two corresponding reference extracts 'S' produced at the authors' laboratory. The set of extracts produced by ALK, Denmark are referred to as 'A', while those produced by Nyco, Norway are referred to as 'N'. The results of the CIE analysis demonstrated that, upon using the same antibodies, both the morphology and the intensity of the precipitates of the different extracts differed considerably. In the alder pollen extract, the 'N' preparation contained more immunoprecipitate lines than the two others. Extract 'S' contained the least number of antigenic lines. Only two of the antigenic lines bound specific IgE in CRIE and were represented in variable concentrations in the three extracts. These two allergenic precipitation lines were demonstrated to have an immunological reaction of identity as shown by tandem-CIE and tandem-CRIE systems, respectively. In the birch pollen system variable numbers of reproducible antigenic lines of precipitation were demonstrated. Preparation 'A' contained more antigens than the two other extracts. This extract lacked a cathodic antigen with slow electrophoretic mobility represented in 'N' and 'S'. One dominant antigenic line was commonly present in the three extracts and could bind IgE antibodies in the CRIE system. A minor cathodic allergen was shown by CRIE in extracts 'S' and 'N', but not in extract 'A'. The RAST and RAST-inhibition titration experiments in all extracts showed qualitative and quantitative similarities. The amino acid compositions and the carbohydrate analyses showed that extracts 'S' and 'N' were similar while extract 'A' contained higher concentrations of certain amino acids and carbohydrates. In both alder and birch pollen, the reference extract 'S' contained lower concentrations of the nonallergenic antigens and of the low molecular weight contaminants.

Allergens↗
PubMed1981

Allergenic synthetic peptide corresponding to the second calcium-binding loop of cod allergen M.

A peptide with the sequence of the second calcium-binding loop (EF loop) of cod Allergen M was synthesized by automatic solid-phase technique. The synthetic peptide corresponded to residues 88-103 of the known primary structure of Allergen M. The immunochemical reactivity of this loop, previously demonstrated for the overlapping enzymic fragments, was confirmed by using the synthetic preparation. The purified hexadecapeptide was shown to bind specifically to reaginic IgE from sera of cod-allergic individuals, in both in vivo and in vitro tests systems. It could also bind rabbit anti-Allergen M, as shown by rocket line immunoelectrophoresis and quantitative precipitation inhibition techniques. The findings emphasized that the immunological reactivity of the synthetic peptide (88-103) was compatible with a monovalent haptenic function: blocking and not eliciting allergic reactions.

Allergens↗
PubMedDate not supplied

Immune-mediated hemolysis associated with the administration of a radiographic contrast medium.

A female patient developed serious hemolysis in association with the injection of a radiographic contrast medium (RCM). Serologic investigation of her serum suggested complement-mediated hemolysis, induced by an RCM-dependent IgM antibody in her serum. The antibody was of high titer and low avidity. The antibody showed cross-reactions with related radiographic contrast media and reacted only with group I adult RBCs.

Complement System Proteins↗