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L Baecher

Publications and source records attributed to L Baecher.

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Further characterization of a low-molecular weight allergen fragment isolated from the green pea.

A low molecular weight allergen fragment present in the pea dialysate fraction was purified by ion-exchange chromatography and gel filtration. The highly purified allergen fragment inhibits both antigen-indiced passive cutaneous anaphlaxix reactions in guinea-pigs sensitized with rabbit anti-pea extract sera and Prausnitz-Küstner reactions in non-allergic volunteers sensitized with the sera of patients sensitive to green peas. Preliminary analysis of the purified allergen fragment indicates that it is a glycoprotein with a molecular weight of 1800 +/- 250.

Allergens

The isolation of allergens from the green pea.

The aqueous extract of green peas was separated into 3 fractions (albumin, legumin, and vicilin) by dialysis against distilled water and isoelectric precipitation. The major antigenic and all of the allergenic activity of the pea extract was associated with the albumin fraction. The albumin fraction retains its allergenicity upon heating at 60 degrees C for 30 min or boiling at 100 degrees C for 5 min, but becomes partially inactivated by autoclaving at 120 degrees C for 15 min. The allergenic determinant expressed by the albumin fraction appears to be common to several other members of the legume family. In addition, the pea dialysate fraction was shown to specifically inhibit precipitin and passive cutaneous anaphylaxis (PCA) reactions involving rabbit antipea serum and the pea albumin fraction, and histamine release from passively sensitized monkey lung tissue using the serum of pea-sensitive patients.

Albumins

Preliminary characterization of a major allergen of timothy grass pollen.

Previous studies with timothy pollen extracts demonstrated that a low molecular weight dialyzable fraction, antigen D, possessed the allergenic determinant of the major allergen of timothy pollen (allergen B). Bio-gel P-2 gel-filtration of the dialysate fraction resulted in the isolation of a fragment, antigen D3 with a molecular weight near 1000. The relationship of antigen D3 to the antigenic and allergenic determinants of allergen B was evaluated by passive cutaneous anaphylaxis (PCA) in guinea pigs sensitized with rabbit antitimothy sera and by allergen-induced histamine release from monkey lung tissue passively sensitized with the serum of timothy-sensitive patients. These studies demonstrated that 10 units of antigen D3 gave 1) a 70% inhibition of PCA reactions in guinea pigs challenged with allergen B, and 2) a 73% inhibition of allergen-induced histamine release from monkey lung tissue sensitized with timothy reagin and challenged with the crude pollen extract (WST). Although chemical characterization studies of the antigen D3 fragment are still being carried out it appears that the major components fo this fragment are 1) a flavonoid pigment - quercitin, 2) a disaccharide moiety - cellobiose, and 3) the amino acid threonine linked together in an )O-glycosidic type linkage.

Allergens