IDENTIFICATION OF A 70 KD PROTEIN WITH SEQUENCE HOMOLOGY TO SQUID NEUROFILAMENT PROTEIN IN GLIAL-CELLS OF THE LEECH CNS

A monoclonal antibody G39, generated against a protein extract of leec h central nervous system, labels specific cell types in adult, embryon ic, and regenerating preparations. The antibody stained glial cells, m icroglial cells, and connective tissue cells, but not neurons or muscl e on cryosections. The staining pattern resembled that of an intracell ular network. Affinity purification of the antigen revealed a 70 kD pr otein. Peptide sequencing showed significant homology of a stretch of 15 amino acids to squid neural filament protein. The same mAb G39 deli neated glial cells as they formed during development of the CNS and sh owed that the giant neuropil glial cells appear before those in the pa ckets. The antigen recognized by mAb G39 represents a nonneuronal inte rmediate filament of the leech Hirudo medicinalis found in various cel l-types such as glia, microglia, and some cells of the connective tiss ue. (C) 1993 John Wiley and Sons, Inc.