RAM, J.L.*; MORALES, J.A.; MERINO, C.R.; YULIS, C.R.: Molluscan nervous system immunoreactivity with antibodies against mammalian Reissner’s fibers glycoproteins and a spondin-like peptide

A polyclonal antiserum (AFRU) against glycoproteins extracted from Reissner’s fiber of non-primate vertebrate nervous systems stains cells in a variety of nervous systems. AFRU antigens resemble, in part, sequences in the thrombospondin superfamily; antibodies raised against a repetitive spondin-like sequence (TSR: GWSEWSPCGPCLPLG) also stain Reissner’s fiber. Although AFRU was originally developed against a mammalian antigen, AFRU immunoreactivity (AFRU-IR) has been shown in CNSs of lower vertebrates, the chordate amphioxus, starfish, grasshopper, etc., often only transiently during early development; however, it has not previously been investigated in mollusks. CNSs of 3 female adult Chorus giganteus, a Chilean gastropod, were fixed in Bouin’s, embedded in paraffin, sectioned, and immunoperoxidase-stained on adjacent serial sections, with AFRU, anti-TSR, and anti-a-CDCP (a molluscan peptide), as primary antibodies. AFRU and anti-TSR IR was co-localized in a small group of cells, resembling neuronal cell bodies, in pedal ganglia. Anti-a-CDCP did not stain cells in the pedal ganglia (negative control for non-specific staining) but did stain a less compact cluster of cell bodies in another ganglion. These results are of interest because (a) this is the first demonstration of AFRU and anti-TSR antigens in a mollusk; (b) stained cell bodies resemble neurons, whereas much previous work with these antibodies has focused on glial cells and extracellular secreted material; (c) staining occurred in adult nervous systems; & (d) co-localization of AFRU and anti-TSR immunoreactivity makes it more likely that the IR material is closely related to previously studied vertebrate AFRU-antigens.