Characterization of a novel Le(x)-active ganglioside from chick intestinal tissues recognized by murine monoclonal antibody 188C1.

A monoclonal antibody, 188C1, raised against skin tissue from the back of bullfrogs (Rana catesbeiana) was found to recognize a common antigen in neural and intestinal tissues of chicken (Fujita, S. (1989) in Biological Transduction Mechanisms (Kasai, M., Yoshioka, T., and Suzuki, H., eds) pp. 159-177, Japan Scientific Societies Press, Tokyo Japan). The 188C1 antigen was isolated from chick intestinal tissues and characterized as a novel ganglioside by means of Q-Sepharose and Iatrobeads column chromatography, and chemical, immunochemical, and immunohistochemical analyses. The chemical structure was as follows: Gal beta 1-4 GlcNAc beta 1-3Gal beta 1-3GalNAc beta 1-4Gal beta 1-4Glc beta 1-1'Cer Fuc alpha 1-3 NeuAc alpha 2-3 This represents a novel hybrid structure of type 2 Le(x) epitope and GM1 ganglioside core structure, designated as Le(x)-GM1. Monoclonal antibody 188C1 reacted strongly with Le(x)-GM1 on thin layer chromatography, but its reactivity was greatly reduced when sialic acid was removed from the antigen. This indicated that the internal sialic acid residue might participate in antigenicity of the Le(x) determinant. In addition to 188C1, a more specific antibody reacting with Le(x)-GM1 but not with asialo-Le(x)-GM1 was raised by immunizing a rabbit with Le(x)-GM1. TLC/enzyme immunostaining using this specific antibody showed the presence of Le(x)-GM1 in chick intestinal tissue, but not in chick brain.