Monoclonal antibodies to proteins of the myelin-like sheath of earthworm giant axons show cross-reactivity to crayfish CNS glia: an immunogold electron microscopy study.

Monoclonal antibodies were generated to the proteins in myelin-like membranes isolated from the nerve cords of the earthworm, Lumbricus terrestris. One of these showing cross-reactivity to 30-32 and 40 kDa proteins was shown by immunofluorescence microscopy and immunogold electron microscopy to be bound primarily to glial cell process and their membranes and the myelin-like layers. This antibody cross-reacted with proteins of 60-65, 42, and 40 kDa in crayfish (Procambarus clarki) nerve cord homogenates. Localization by immunoelectron microscopy showed the antibody to be bound exclusively to the membranes of the glial processes ensheathing the axons in the crayfish nerve cord. Thus, the proteins in earthworm and crayfish glial cell membranes have some epitopes in common. We suggest that this may represent an evolutionary conservation of these proteins.