Isolation of a Purified Allergen from Kentucky Blue Grass Pollen

Abstract

An allergenic fraction, designated as C-I-2–6, was isolated from among the allergenic constituents present in the dialysate of the aqueous extract of defatted Kentucky blue grass (KBG) pollen by a combination of gel filtration, ion-exchange chromatography and preparative isoelectrofocussing. This fraction was shown to consist of glycoprotein with a molecular size corresponding to 10,000 daltons and of two components with closely related pI values (4.5–4.9); its protein moiety contained all the amino acids except cysteine. As demonstrated by crossed immunoelectrophoresis with a sheep anti-R serum, fraction C-I-2–6 shared the antigenic determinants of 2 of the 15 antigenic components of the non-dialysable components, i.e. retentate (R) of the aqueous extract of KBG pollen. Remarkably, in spite of the markedly lower molecular weight than R, fraction C-I-2–6 possessed all the allergenic determinants of R responsible for inducing murine IgE antibodies.