Non-IgG1 nature of cutaneous basophil hypersensitivity factor in contact sensitivity

Cutaneous basophil hypersensitivity (CBH)-inducing factor was demonstrated in immune sera obtained from dinitrofluorobenzene (DNFB)-sensitized animals 2 weeks after sensitization (DNP-GPS-2W). It showed hapten specificity and worked dose dependently. It was fractionated into a non-gamma-globulin fraction by Sephadex G-150 gel filtration following ammonium sulfate desalting and CM-cellulose chromatography. The factor was eluted into a fraction of a little smaller molecular weight than bovine serum albumin on Sephadex G-150 gel filtration. It passed through an antiguinea pig IgG1 column and was absorbed to a DNP-BGG column. On SDS-PAGE it failed to show any staining band because of low protein concentration. From these results CBH factor appearing in circulation in contact-sensitized animals was thought to be a somewhat different molecule from that of Askenase's factor, i.e. IgG1 antibody.