The indirect immunoperoxidase method was used to localize histologically on sagittal sections of mouse cerebellum antigenic determinants detected by the following antisera: anti-NS-2, anti-NS-3, anti-NS-4 rabbit anti-bovine corpus callosum, rabbit anti-mouse brain, rabbit anti-glial fibrillary acidic protein, and rabbit anti-neurofilament protein. Anti-alpha-bungarotoxin serum and normal rabbit serum were used as negative controls. The various sera showed similarities in staining pattern as well as differences. Anti-NS-2 antiserum labeled the somata of interneurons in the molecular layer, granule cell bodies, glial cells in the white matter, and along the surfaces of blood vessels. A similar pattern of staining is produced by the anti-NS-3 antiserum except that glial cells are less prominent in the white matter and the blood vessels are not visible at all. Anti-NS-4 antiserum does not label interneurons but does label glomeruli and, less intensely, granule cell bodies in the granular layer. Rabbit anti-mouse brain antiserum is similar to anti-NS-4 antiserum except that fiber tracts in the white matter are stained more intensely; Rabbit anti-bovine corpus callosum labels only white matter. Antisera to neurofilament ans astrocytes.

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PubMedDate not supplied

Characterization of an antiserum to synaptic glomeruli from rat cerebellum.

Rabbit anti-rat cerebellar synaptic glomeruli antiserum when absorbed with non-neural tissues reacts only with neural tissues when tested by indirect immunofluorescence on tissue sections. Further absorption with forebrain results in the antiserum which detectably reacts only with synaptic glomeruli and soma of Purkinje cells of both rat and mouse. The developmental expression of the synaptic glomeruli antigen(s) parallels the formation of synapses between mossy fibers and granule cells. Immature synaptic contacts do not contain recognizable antigen(s), whereas only at postnatal Day 15 glomeruli become antigen-positive. At this stage antigen in Purkinje cells is no longer carried in their dendrites, but becomes confined to the cell soma. Staggerer mutant mice still express the immature pattern of antigen distribution on postnatal Day 18.

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PubMedDate not supplied

L1 mono- and polyclonal antibodies modify cell migration in early postnatal mouse cerebellum.

A major event of nervous system development is the migration of granule cell neurones, during the early postnatal development of the cerebellar cortex, from their germinating zone in the external granular layer to their final location in the internal granular layer. During migration, many granule cells are seen in direct cell-surface contact with processes of Bergmann glia, a subclass of astrocytes. In the neurological mutant mouse weaver, however, migration of granule cells is impaired, probably due to a deficit in cell-cell interactions. To gain insight into the cellular and molecular mechanisms involved in granule cell migration, we have used a modification of an in vitro assay system, previously described by Moonen et al., which displays migratory behaviour in small tissue explants during several days of suspension culture. The aim of this study was to investigate the process of granule cell migration by using antibodies directed against cell-surface components of developing neural cells. We report here that migration of 3H-thymidine-labelled granule cell neurones can be modified by Fab fragments of both mono- and polyclonal L1 antibodies, but not by Fab fragments of polyclonal antibodies prepared against mouse liver membranes, which also react with cerebellar cell surfaces.

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PubMedDate not supplied

Neural cell adhesion molecules and myelin-associated glycoprotein share a common carbohydrate moiety recognized by monoclonal antibodies L2 and HNK-1.

Cell surface molecules have been implicated in cell interactions which underlie formation of the nervous system. The analysis of the functional properties of such molecules has profited from the combined use of antibodies and cell culture systems. It has been suggested that the interplay between these molecules modulates cell-to-cell interaction at critical developmental stages. In the mouse, N-CAM and L1 antigen have been shown to mediate Ca2+-independent adhesion among neural cells. N-CAM plays a role in fasciculation of neurites and formation of neuromuscular junction. L1 is apparently not involved in synaptogenesis, but in migration of granule cell neurones in the developing mouse cerebellar cortex. The two antigens are distinct molecular and functional entities which act synergistically in aggregation of neuroblastoma and early postnatal cerebellar cells. In view of a certain similarity in function between the two groups of molecules, it was not surprising to find that structural similarities are detectable by the monoclonal antibody L2. We show here that a carbohydrate moiety recognized by L2 and HNK-1 monoclonal antibodies, is present in mouse N-CAM and L1. The L2 epitope appears on all major neural cell types but not all N-CAM molecules express it. This heterogeneity points to a previously undetected molecular diversity which may have functional implications for modulating cell adhesion during development.

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PubMedDate not supplied

The J1 glycoprotein--a novel nervous system cell adhesion molecule of the L2/HNK-1 family.

The neural cell adhesion molecules L1 and N-CAM share a common carbohydrate epitope that is recognized by the monoclonal antibodies L2 and HNK-1. The L2/HNK-1 epitope is also present on the myelin-associated glycoprotein (MAG) which is thought to mediate surface interactions between the axon and myelinating cell. Other, as yet unidentified, cell-surface glycoproteins are recognized by the two antibodies and are believed to belong to a family of neural cell adhesion molecules. To test this hypothesis, we have prepared polyclonal antibodies to a prominent member of the L2/HNK-1 family, the 160K (relative molecular mass (Mr)160,000) glycoprotein. Here we report that these antibodies, designated J1 antibodies, react with astrocytes and oligodendrocytes and interfere with neurone-astrocyte adhesion, but not with neurone-neurone or astrocyte-astrocyte adhesion. This result suggests the involvement of the J1 antigen in cell-cell interactions.

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PubMedDate not supplied

Differential inhibition of neurone-neurone, neurone-astrocyte and astrocyte-astrocyte adhesion by L1, L2 and N-CAM antibodies.

The cell adhesion molecules L1, N-CAM and Ng-CAM have been implicated in cell-cell interactions among developing neural cells. L1 and N-CAM are structurally and functionally distinct molecular entities and act synergistically in mediating Ca2+-independent adhesion between re-aggregating early postnatal cerebellar cells. N-CAM has been reported to be neurone-specific in the chicken and to mediate fasciculation of neurites and of nerve-muscle interactions. L1, which in the central nervous system has been found only on post-mitotic neurones, mediates migration of granule cell neurones in the mouse cerebellar cortex. In view of the molecules' distinct effects on cell interactions, we wondered whether different neural cell types are involved in the actions of each molecule. Here we report that L1 antigen promotes neurone-neurone adhesion. N-CAM, which is expressed on both neurones and glia, mediates neurone-neurone, neurone-astrocyte and astrocyte-astrocyte adhesion. The L2 carbohydrate epitope shared between the two adhesion molecules seems to be involved in neurone-astrocyte and astrocyte-astrocyte adhesion and acts in a more than additive manner in N-CAM-mediated neurone-neurone adhesion.

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PubMedDate not supplied

Differentiation state-dependent surface mobilities of two forms of the neural cell adhesion molecule.

The neural cell adhesion molecule (N-CAM) has been implicated in morphogenetic events during formation of the nervous system. Three forms of N-CAM exist, all glycoprotein chains, of relative molecular masses 180,000 (180K), 140K and 120K (N-CAM180, N-CAM140 and N-CAM120) which are differentially expressed on neural cell types and during development. The three chains are thought to carry similar if not identical amino-acid sequences on their extracellular amino-terminal domains, but differ in the length of their carboxy-terminal cytoplasmic region. They occur in highly sialylated embryonic and less sialylated adult forms. N-CAM180 is selectively expressed in more differentiated neural cells and may play a role in the stabilization of cell contacts. To investigate this, we have studied in the surface membrane of a mouse neuroblastoma cell line N2A the lateral mobility of the two predominant forms of N-CAM, N-CAM180 and N-CAM140, as a function of differentiation. Here we report that as judged by fringe pattern photobleaching, the surface mobility of N-CAM140 is higher than that of N-CAM180, suggesting an association of N-CAM180 with the cytoskeleton or other stabilizing factors. We also show that brain spectrin, a membrane-cytoskeleton linker protein, binds only to N-CAM180. The immobilization of N-CAM in differentiated N2A cells is achieved by a shift in expression from N-CAM140 to N-CAM180.

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PubMedDate not supplied

Hippocampal long-term potentiation and neural cell adhesion molecules L1 and NCAM.

Synaptic membranes express cell adhesion molecules. Here we investigate the role of the neural cell adhesion molecules L1 and NCAM in hippocampal long-term potentiation (LTP), a sustained-use-dependent increase in synaptic efficacy that has been implicated in learning and memory. L1 and NCAM mediate cell interactions during neural development and are strongly expressed in the hippocampus. They cooperate to strengthen L1-dependent cell adhesion and are coupled to second messenger pathways. We show that LTP in CA1 neurons of rat hippocampal slices was reduced by application of various L1 and NCAM antibodies, recombinant L1 fragments, and upon dissociation of the L1/NCAM complex through oligomannosidic carbohydrates and NCAM peptides. Neither the activation of NMDA (N-methyl-D-aspartate) receptors nor the maintenance of LTP was affected. These results suggest that L1 and NCAM modulate the development or the stabilization of LTP.

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PubMedDate not supplied

A role for a chicken homolog of the neural cell adhesion molecule L1 in consolidation of memory for a passive avoidance task in the chick.

Intracranial injection of antibodies directed against the neural cell adhesion molecule L1 resulted in amnesia for passive avoidance training in day-old chicks tested 24 hr subsequently. L1 antibodies were amnesic when administered at one of two time windows: 30 min pretraining and 5.5-8 hr post-training. No amnesia was apparent if injections were made at times before, between, or after these time windows (-2, +1, +3, +4, or +12 hr relative to training). A fragment of the L1 molecule derived from the external fibronectin domains FN1-5 produced amnesia only when injected at the 5.5-hr timepoint, whereas a fragment of the immunoglubin-like domains Ig I-VI produced amnesia only when injected 30 min prior to training. We have shown previously that long-term memory for the passive avoidance task requires two waves of glycoprotein synthesis, the first occurring immediately after training, and the second some 6 hr thereafter. The glycoprotein synthesis inhibitor 2-deoxygalactose results in amnesia if injected at either time, whereas the neural cell adhesion molecule (N-CAM) is specifically involved only in the second wave. The coincidence of the time course of memory disruption resulting from injection of L1 antibodies with that occurring with 2-deoxygalactose supports the hypothesis that establishment of an enduring memory for the experience of passive avoidance training requires two waves of glycoprotein synthesis, each wave being biochemically and functionally discrete. The differential effects of the two L1 fragments suggests that separate mechanisms of synaptic stabilization are involved at the two time points.

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PubMedDate not supplied

Binding of mistletoe lectins to cutaneous malignant melanoma: implications for prognosis and therapy.

BACKGROUND: Glycoconjugates, as detected by lectin histochemistry, have been implicated in metastasis formation in many neoplasias. However, no data concerning the three mistletoe lectins (MLs) and the spread of malignant melanoma have been published. MATERIALS AND METHODS: The binding status of ML-I, -II and -III was histochemically assessed in 100 malignant melanomas and correlated with metastasis in a 10 year follow-up period. Furthermore, the staining intensity of the three MLs, scored from negative (-) to very intense (+ + +), was evaluated. RESULTS: Kaplan-Meier analsis revealed that very intense binding (+ + +) of ML-I was positively-correlated with metastasis (p=0.044). CONCLUSION: Since ML-I is specific for galactose, high density galactose expression in malignant melanoma is a predictor of poor prognosis.

Adjuvants, Immunologic↗