Non-IgG1 Nature of Cutaneous Basophil Hypersensitivity Factor in Contact Sensitivity

Abstract

Cutaneous basophil hypersensitivity factor (CBH-F) from the sera of 1-fluoro-2,4-dinitrobenzene contact-sensitized guinea pigs promoted histamine release from bone marrow basophils in the presence of the antigen, dinitrophenylated epidermal microsomes as well as in vivo activity to induce CBH reaction in naive recipients and in vitro activity to mediate antigen-dependent basophil chemotaxis. The amount of histamine released was around 20% of the total release when compared to that of concanavalin A-induced basophil degranulation (50-60%). Divalent cations were required in this reaction because addition of EDTA completely suppressed histamine release from passively sensitized basophils with CBH-F. Though it is not known at present whether the same molecule is involved in basophil chemotaxis and histamine release, this histamine-releasing activity was recovered in the same preparations with basophil chemotactic activity after several purification steps.