Isolation and partial characterization of allergen C from Kentucky blue grass pollen

An allergenic component, designated as Allergen C, was isolated from the retentate (R) of the aqueous extract of defatted Kentucky blue grass (KBG) pollen by a combination of preparative isoelectrofocussing and gel filtration. Allergen C was found to be a glycoprotein with molecular size of the order of 11,000 daltons and had a pI value of approximately 9.7. It possessed all the allergenic determinants collectively present in R. The allergenic activity was found to be associated with the protein moiety of the molecule. Allergen C was one of the 15 antigenic components detectable in R by crossed immunoelectrophoresis with a hyperimmune sheep antiserum to R. Observations based on enzymatic degradation of the molecule suggested that the determinants recognized by murine IgE antibodies were different from those which combined with rabbit precipitating antibodies.