title: Comparative studies on tree pollen allergens. VII. Monomethoxy polyethylene glycol conjugation of the major allergen of birch pollen (Betula verrucosa).
abstract: 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)
mesh_terms: D000596:Amino Acids / Q000032:analysis; D002850:Chromatography, Gel; D000939:Epitopes; D006241:Haptens / Q000276:immunology; D007120:Immunochemistry; D007457:Iodine Radioisotopes; D011058:Pollen / Q000276:immunology*; D011092:Polyethylene Glycols / Q000276:immunology; D011852:Radioallergosorbent Test; D014197:Trees
chemical_list: D000596:Amino Acids; D000939:Epitopes; D006241:Haptens; D007457:Iodine Radioisotopes; D011092:Polyethylene Glycols