Monoclonal antibodies against squid axolinin (the 260-kD glycoprotein in squid axoplasm) have been produced using spleen cells immunized with purified axolinin in vivo and in vitro. The produced antibodies can be categorized into two groups according to the nature of their antigenic site. The monoclonal antibodies belonging to group I recognize the protein backbone of axolinin, while those belonging to group II bind to the sugar chains of axolinin. Group II was further divided into two subgroups IIA and IIB; the subgroup IIA antibodies recognize sugar chains to which concanavalin A binds, while the IIB antibodies bind to sugar chains lacking the lectin-binding sites. Only the group I antibodies can be used as specific probes for axolinin since the sugar chains recognized by the group II antibodies are present on other squid glycoproteins in addition to axolinin. It follows from our results that polyclonal antisera against axolinin cannot generally be expected to be specific for this protein.
