Methyl α-D-Fucopyranoside, 

甲基-α-D-吡喃岩藻糖苷,

Methyl a-D-fucopyranoside is a monoclonal antibody that binds to the O-antigen of the polysaccharide chain. It is a synthetic trisaccharide consisting of an o-antigen, an α-linked D-fucose residue, and an α-linked galactose residue. This antibody interacts with the serologic subtypes of Group A Streptococcus, but not with other serogroups. Methyl a-D-fucopyranoside utilizes conformational epitopes and disaccharides which are not accessible to other antibodies in order to bind to the o-antigen. The o-antigen is composed of two serologically distinct regions: one region for binding by anti-A antibodies, and another for binding by anti-B antibodies.