Antigenic sites common to major fish myelin glycoproteins (IP) and to major tetrapod PNS myelin glycoprotein (Po) reside in the amino acid chains.

The major myelin glycoproteins in the CNS and PNS of trout (IP) were enzymatically deglycosylated with endoglycosidase F (Endo F) and examined by electro-immunoblotting. Following carbohydrate removal and loss of concanavalin A affinity each of the four IP components underwent a similar reduction in molecular size, corresponding to approximately 3,000 daltons. Immunological cross-reactivities with anti-bovine Po or anti-trout IP2 antibodies, were however fully retained by the Endo F cleavage products. This strongly implies that the antigenic sites shared by the mammalian Po protein and the various intermediate glycoproteins of trout CNS and PNS are located in the protein portion. Immunoblot analysis of the PNS myelin proteins from various species of the major vertebrate classes with anti-trout IP2 antiserum revealed striking differences in the immunological properties of the individual Po components which were not detected when anti-bovine Po antiserum was used as a probe.