Abstract
We have investigated the distribution of ganglioside GM3 in normal skin with 8G9D8, a monoclonal antibody against GM3, and found binding to the stratum corneum. By electron microscopy, strong deposition of antibody was seen at the corneocyte envelope/"plasma membrane" region. Significantly decreased to absent binding to the stratum corneum was shown in a variety of disorders of excessive keratinocyte proliferation, including squamous cell carcinomas, psoriasis, and bullous and non-bullous forms of congenital ichthyosiform erythrodermas, as well as in the hyperplastic cornoid lamellae of porokeratosis. The 8G9D8 antibody recognizes the carbohydrate sequence N-acetylneuraminic acid alpha 2----3 galactose beta 1----4 glucose (or N-acetylglucosamine). Thus, in addition to ganglioside GM3, 8G9D8 may bind to glycoproteins or another glycolipid of the stratum corneum with a shared carbohydrate sequence. The carbohydrate sequence recognized by 8G9D8, whether attached to an epidermal glycoprotein or glycolipid, may prove to be important in keratinocyte proliferation and differentiation.
