Targeted gene therapy to antigen-presenting cells in the central nervous system using hematopoietic stem cells

BACKGROUND

Hematopoietic stem cells (HSC) have been previously used as vectors for gene therapy of systemic disease. The effectiveness of HSC-mediated gene therapy largely depends on efficient gene delivery into long-term repopulating progenitors and targeted transgene expression in an appropriate progeny of the transduced pluripotent HSCs. In the present study, we examined the feasibility of using HSC transduced with self-inactivating (SIN) lentiviral vectors for the delivery of gene therapy to the central nervous system (CNS).

MATERIAL AND METHODS

We constructed two SIN lentiviral vectors, EF.GFP and DR.GFP, to express the green fluorescent protein (GFP) gene controlled solely by the promoter of either a housekeeping gene EF-1alpha or the human HLA-DRalpha gene, which is selectively expressed in antigen-presenting cells.

RESULTS

We demonstrated that both vectors efficiently transduced human pluripotent CD34+ cells capable of engrafting NOD/SCID mice. Only the DR.GFP vector mediated transgene expression in the murine CNS containing human HLA-DR+ cells. These cells express surface markers characteristic of resident CNS microglia. Furthermore, human dendritic cells derived from transduced and engrafted human cells potently stimulated allogeneic T cell proliferation.

CONCLUSIONS

The present study demonstrated successful targeting of transgene expression to CNS microglia after stable gene transduction of pluripotent HSC.

Detection of IL-20R1 and IL-20R2 mRNA in C57BL/6 mice astroglial cells and brain cortex following LPS stimulation

BACKGROUND

Astrocytes, which comprise ~90% of overall brain mass, are involved in brain immunity. These cells represent the non-professional class of CNS-resident APCs and may promote or inhibit CNS inflammation depending on the cytokines they secrete. IL-10 family of cytokines and their receptors, IL-20R1 and IL-20R2, may have a role in shifting astrocytes to a neuroprotective or neurodegenerative function.

OBJECTIVE

To address the expression of IL-20R1 and IL-20R2 cytokine receptors in astrocytes and brain cortex of C57BL/6 mice.

METHODS

We investigated the expression of IL-20R1 and IL-20R2 in C57BL/6 mice astroglial cells and brain cortex in response to lipopolysaccharide (LPS), using reverse-transcription polymerase chain reaction (RT-PCR) method.

RESULTS

Astrocytes were able to express IL-20R1 and IL-20R2 mRNA not only in response to LPS stimulation but also in the absence of LPS. Furthermore, we found the expression of IL-20R1 and IL-20R2 mRNA in the cortex of adult C57BL/6 mice.

CONCLUSIONS

IL-20R1 and IL-20R2 are constitutively express in the brain. Since most neuropathological processes involve astrocytes and inflammatory cytokines, these findings have important implications for future therapeutic strategies.

Expression of Toll-like receptor 3 in the human cerebellar cortex in rabies, herpes simplex encephalitis, and other neurological diseases

There is recent in vitro evidence that human neurons express the innate immune response receptor, Toll-like receptor-3 (TLR-3), and that expression is enhanced in viral infections. The authors examined the immunohistochemical expression of TLR-3 in the cerebellar cortex of postmortem human brains. Purkinje cells were found to express TLR-3 in all cases of rabies (4 of 4) and herpes simplex encephalitis (2 of 2) as well as in cases of amyotrophic lateral sclerosis (1 of 2), stroke (1 of 2), and Alzheimer's disease (3 of 3). In cases of viral infection, direct viral infection was not necessary for enhanced neuronal TLR-3 expression, suggesting that soluble factors likely play an important role in inducing TLR-3 expression. In addition to neurons, occasional Bergmann glia expressed TLR-3 in some cases. This study has provided evidence that human brain neurons can express TLR-3 in vivo and suggests that neurons may play an important role in initiating an inflammatory reaction in a variety of neurological diseases.

Interleukin-6 produces neuronal loss in developing cerebellar granule neuron cultures

CNS levels of the cytokine interleukin-6 (IL-6) are elevated during CNS injury and disease, but it is unclear if IL-6 contributes to the pathologic process. Our studies show that in a well-characterized CNS developmental model system, primary cultures of rodent cerebellar granule neurons, chronic exposure to IL-6 during neuronal development can result in cell damage and death in a subpopulation of developing granule neurons. Chronic exposure to IL-6 also increased the susceptibility of the granule neurons to a toxic insult produced by excessive activation of NMDA receptors. These results are consistent with a role for IL-6 in the neuropathology observed in the developing CNS during injury and disease.

Abnormal Purkinje cell activity in vivo in experimental allergic encephalomyelitis

Cerebellar deficits in multiple sclerosis (MS) tend to persist and can produce significant disability. Although the pathophysiological basis for these deficits is not clear, it was recently reported that the expression of the sensory neuron-specific sodium channel Nav1.8 (which is not normally expressed within the cerebellum) is aberrantly upregulated within Purkinje cells in experimental allergic encephalomyelitis (EAE) and in human MS. The expression of Nav1.8 in cultured Purkinje cells has been shown to alter the activity pattern of these cells in vitro by decreasing the number of spikes per conglomerate action potential and by contributing to the production of sustained, pacemaker-like activity upon depolarization, suggesting the hypothesis that, in pathophysiological situations where Nav1.8 is upregulated within Purkinje cells, the pattern of activity in these cells will be altered. In the present study, we examined this hypothesis in vivo in mice with EAE. Our results demonstrate a reduction in the number of secondary spikes per complex spike and irregularity in the temporal organization of secondary spikes in Purkinje cells from mice with EAE in which Nav1.8 is upregulated. We also observed abnormal bursting activity in Purkinje cells from mice with EAE, which was not observed in control animals. These results demonstrate functional changes in Purkinje cells in vivo within their native cerebellar environment in EAE, a model of MS, and support the hypothesis that misexpression of Nav1.8 can contribute to cerebellar deficits in neuroinflammatory disorders by altering the pattern of electrical activity within the cerebellum.

Increased sensitivity to N-methyl-D-aspartate receptor-induced excitotoxicity in cerebellar granule cells from interleukin-1 receptor type I-deficient mice

The effects of chronic exposure to excitatory amino acids (EAAs) were examined in cultured cerebellar granule cells (CGCs) from wild type (WT) and interleukin-1 receptor type I (IL-1RI)-deficient mice. After 8 days in culture, the cells were exposed to 100 microM glutamate or 300 microM N-methyl-D-aspartate (NMDA) for 24 h. Analysis of cell viability, as assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction assay and phase-contrast microscopy revealed that CGCs from IL-1RI-deficient mice were more vulnerable to EAAs as compared to the WT controls. The results indicate that IL-1RI signalling is important for neuronal survival. The effect of glutamate on the CGCs from IL-1RI-deficient mice was decreased by the non-competitive NMDA-receptor antagonist MK-801, supporting the involvement of NMDA receptors in the glutamate-induced excitotoxicity.

[Paraneoplastic cerebellar degeneration associated with ovarian cancer: anti-Yo immunoreactivity in autoptic cerebellum and ovarian carcinoma]

Paraneoplastic cerebellar degeneration is a rare disorder caused likely by autoimmune mechanisms in malignant oncologic diseases, and the most common tumors are ovarian, breast, lung cancer, and m. Hodgkin. An immune reaction is supposed to be directed against identical antigens of cerebellum and tumor, and paraneoplastic antibodies called anti-Yo, anti-Hu, anti-Ri, or anti-Tr are often detected in blood and cerebrospinal fluid. The course of paraneoplastic cerebellar degeneration as a complication of ovarian cancer is described. The relationship between the malignancy and pathologic changes in cerebellum was confirmed by positive immunohistochemical and immunofluorescence reaction between a patient's anti-Yo-positive serum and her own Purkinje's and ovarian cancer cells.

Chemokine receptor CXCR2 regulates the functional properties of AMPA-type glutamate receptor GluR1 in HEK cells

Experiments were conducted in both HEK cells and cerebellar neurons to investigate whether CXC chemokine receptor 2 (CXCR2) is functionally coupled to GluR1. The co-expression of CXCR2 with GluR1 in HEK cells increased (i) the GluR1 "apparent" affinity for the transmitter; (ii) the GluR1 channel open probability; and (iii) GluR1 binding site cooperativity upon CXCR2 stimulation with CXC chemokine ligand 2 (CXCL2). The affinity of C-terminal-deleted GluR1 for glutamate (Glu) remained stable instead. Furthermore, CXCL2 increased the binding site cooperativity of AMPA receptors in rat cerebellar granule cells; and the amplitude of spontaneous excitatory postsynaptic current (sEPSCs) in Purkinje neurons (PNs). Our findings indicate that the coupling of CXCR2 with GluR1 may modulate glutamatergic synaptic transmission.

Microglial cells protect cerebellar granule neurons from apoptosis: evidence for reciprocal signaling

The microglia are the immune cell population of the nervous system and play important roles both in normal function and in disease. Reciprocal neuron-microglia interactions are not well understood, in particular those concerning the crosstalk between the two cell populations when neuronal damage does occur. We have used a well-established model of apoptosis in cerebellar granule neurons to test the effect of co-culturing microglial cells with them or of exposing them to microglia-conditioned medium. Microglial cells, derived from cortical or cerebellar mixed glial cultures and plated over cerebellar granule neurons, protected these neurons from apoptosis induced by shifting them, at 7 days in vitro, for 24 h from a depolarizing (high-potassium) to a nondepolarizing (low-potassium) medium. The same result was achieved when microglial cells obtained from mixed glial cortical cultures were plated over a membrane well insert in the culture chamber, permitting medium exchange without physical contact with granule neurons. A similar result was obtained when the low-potassium, apoptosis-inducing medium was conditioned by 48-h exposure to microglial cells; 24-h exposure to microglial cells was not enough to confer neuroprotective capability to the conditioned medium. However in double-conditioned medium experiments, in which the medium was first exposed to apoptotic neurons and then to microglial cells, unknown signal(s) released by apoptotic neurons, conferred to the 24-h conditioned medium a strong neuroprotective action, similar to that observed in the co-cultures experiments. This finding, together with the results from co-culture experiments, is explained by admitting that molecules released in the medium by apoptotic neurons potentiate the anti-apoptotic activity of microglia. Our results, therefore, demonstrate not only that normally microglial cells release in the medium molecule(s) able to rescue neurons from apoptotic death, but that unknown diffusible signal(s) from apoptotic neurons enhance(s) microglial neuroprotective properties as well.

Presynaptic impairment of cerebellar inhibitory synapses by an autoantibody to glutamate decarboxylase

Glutamic acid decarboxylase (GAD), the enzyme responsible for converting glutamate to gamma-aminobutyric acid (GABA), is a target of humoral autoimmunity in stiff-man syndrome and subacute cerebellar ataxia. Recently, we found that an anti-GAD autoantibody in the CSF of an ataxic patient selectively suppressed GABA-mediated transmission on cerebellar Purkinje cells without affecting glutamate-mediated transmission. Here, we examine the mechanism by which the autoantibody impaired the inhibitory transmission, using immunohistochemistry and whole-cell recording in rat cerebellar slices. The present results indicate that CSF immunoglobulins prepared from an ataxic patient acted on the presynaptic terminals of GABAergic interneurons and decreased GABA release onto Purkinje cells.

The organization of neurofilaments accumulated in perikaryon following aluminum administration: relationship between structure and phosphorylation of neurofilaments

Neurofilaments accumulated in perikarya and dendrites of anterior horn cells and Purkinje cells of rabbit treated by aluminum chloride were analysed with a variety of techniques. Four different monoclonal antibodies against phosphorylated and nonphosphorylated epitopes on neurofilament H subunit were used to compare phosphorylation state of these accumulated neurofilaments with that of axonal neurofilaments. Although immunoblotting revealed no significant difference in phosphorylation between control and aluminum-treated brains, accumulated neurofilaments were immunocytochemically more phosphorylated than control perikaryal or dendritic neurofilaments. With detailed analysis of cryothin-section immunogold labeling, accumulated neurofilaments were, however, significantly less phosphorylated than axonal neurofilaments. With quick-freeze deep etching, core filaments of accumulated neurofilaments are as dense as axonal neurofilaments but much less regularly aligned. Cross-bridges of accumulated neurofilaments were less frequent and more branched than those of axonal neurofilaments, and when examined with combined immunocytochemistry and deep etching, were less phosphorylated. These results suggest that there is a relationship between the phosphorylation and the structural organization of neurofilaments. The phosphorylation of neurofilament H subunit may be necessary for formation of frequent and straight cross-bridges and resulting regular alignment of core filaments.

Antigenic compartmentation in the mouse cerebellar cortex: zebrin and HNK-1 reveal a complex, overlapping molecular topography

Two monoclonal antibodies--anti-zebrin I and anti-HNK-1--have been used to study the compartmentation of the mouse cerebellar cortex. As in other species, the pattern of localization of the Purkinje cell specific antigen zebrin I is confined to a subset of Purkinje cells that are organized into parasagittal bands. The basic pattern consists of two abutting paramedian bands (P1+) and up to three additional vermal bands on either side (P2(+)-P4+). This pattern is altered in the vermal regions of lobules X and VI-VII where all Purkinje cells are immunoreactive. In the hemisphere there are three additional bands present (P5(+)-P7+) plus two shorter bands in the paravermal area (P4b+ and P5a+) that extend from the paramedian lobule through the lobulus simplex. This pattern is very similar, but perhaps not identical, to that previously described for the rat. These results suggest a common mammalian plan for the expression and localization of zebrin I. By using a monoclonal antibody to an epitope associated with HNK-1, we have now identified a novel pattern of compartmentation in mouse cerebellum. The HNK-1 epitope is expressed most notably on Purkinje cells and Golgi cells. The molecular layer immunoreactivity associated with the Purkinje cell dendrites varies in intensity in a systematic and reproducible fashion. This reveals a novel cerebellar compartmentation that is sometimes complementary, sometimes overlapping, to that revealed by anti-zebrin. As a result, it is now possible to subdivide the cerebellar cortex into a still finer mosaic of antigenic patches and bands than was possible by using zebrins alone.

The new monodendritic neuronal type within the adult human cerebellar granule cell layer shows calretinin-immunoreactivity

The distribution of calretinin immunoreactive structures within the granule cell layer of the adult human cerebellar cortex was studied using the avidin-biotin peroxidase method. Immunoreactivity is found in numerous fibers and glomerular formations, in Golgi- and Lugaro cells as well as in a recently described novel neuronal type, the monodendritic cell. The soma of the monodendritic neuron contains a faintly stained nucleus and issues a single short dendrite terminating in a tuft. Most probably, the tuft contributes to the formation of a glomerulum. Soma and tuft are of about the same size (diameter 10-18 microns). The number of monodendritic neurons is higher in the vermal than in the hemispheric part of the lobulus (lobulus VII) and is higher in lobulus X than in lobulus VII of the vermis.

Immunohistochemical visualization of a metabotropic glutamate receptor

The immunocytochemical localization of the recently cloned metabotropic glutamate receptor 1 alpha (mGluR1 alpha) was demonstrated with a C-terminus specific antibody in rat cerebellar cortex. This antibody detects a 138-140 kDa major, and a 46 kDa minor band in membrane preparations of rat cortex and cerebellum. mGluR1 alpha immunoreactivity (mGRi) was present in Purkinje and basket cells. Purkinje cell dendritic spines and their postsynaptic membranes showed selective labelling. Presynaptic membranes, parallel fibres and glial processes were devoid of mGRi. It is suggested that the selective postsynaptic localization of this receptor at the dendritic spines of Purkinje cells serves as the morphological basis for long term depression processes in the molecular layer of the cerebellar cortex.

Differential subcellular distribution of the alpha 6 subunit versus the alpha 1 and beta 2/3 subunits of the GABAA/benzodiazepine receptor complex in granule cells of the cerebellar cortex

The distribution of the alpha 6 subunit of the GABAA receptor has been established in rat cerebellum and compared to the distribution of the alpha 1 (cat) and the beta 2/3 (rat, cat) subunits, using immunocytochemistry. The synapses established by Golgi cell terminals on the dendrites of granule cells were immunoreactive for the alpha 6, alpha 1 and beta 2/3 subunits in virtually all glomeruli, indicating that two variants (alpha 1 and alpha 6) of the same subunit are co-localized at the same synapses. The somatic membranes of the granule cells, which receive no synapses, were immunopositive for the alpha 1 and beta 2/3 subunits, but not for the alpha 6 subunit. Thus, the alpha 1 and the beta 2/3 subunits are located at both synaptic and extrasynaptic sites, but the alpha 6 subunit is detectable only at synaptic sites.

Destruction of meningeal cells over the medial cerebral hemisphere of newborn hamsters prevents the formation of the infrapyramidal blade of the dentate gyrus

Meningeal cells participate in the development of the cerebellum both by stabilizing the extracellular matrix of the pial surface and by organizing the radial glial scaffold and the lamination of the cerebellar cortex. In the present study we investigated possible influences of meningeal cells on the development of the dentate gyrus, whose ontogenesis has many similarities to that of the cerebellum. Meningeal cells were selectively destroyed by injecting newborn hamsters with 25 micrograms 6-hydroxydopamine (6-OHDA) into the interhemispheric fissure. Twenty-four hours postinjection (p.i.) the meningeal cells over the medial cerebral hemispheres were completely destroyed. Thirty days p.i. the infrapyramidal blade of the dentate gyrus was almost completely missing, while the suprapyramidal blade was hypertrophied, extending with its medial tip almost up to the medial surface of the cortex. In order to ascertain that this maldevelopment was caused by the destruction of meningeal cells, another group of hamsters was pretreated with normetanephrine (NMN) which inhibits the extraneuronal uptake of 6-OHDA into meningeal cells. In this group the meningeal cells were unaffected by the treatment, and the morphology of the dentate gyrus was normal 30 days p.i. of 6-OHDA plus NMN. When the meningeal cells were destroyed in later stages of development (postnatal days 1-5), alterations of the dentate gyrus could be induced only up to the fourth postnatal day; thereafter, 6-OHDA treatment left it unchanged. This indicates a critical period of meningeal cell influence that coincides with the period of existence of the subpial dentate matrix. Analysis of the time course of the defective development revealed that in the first 5 days p.i. 1) meningeal cells over the medial cerebral hemisphere were destroyed and removed, 2) the pial basement membrane over both the dentate anlage and the diencephalon thinned and ruptured, and the adjacent brain parts fused focally, 3) many cells of the subpial dentate matrix disappeared from their subsurface position, 4) the number of "immature" cells increased in the hilus and the subgranular zone of the suprapyramidal blade, 5) the suprapyramidal blade elongated and thickened considerably, while the infrapyramidal blade did not form. Beyond 5 days p.i. those parts of the pial surface of the dentate anlage that had not fused with the diencephalon were repopulated with meningeal cells. This reappearance of meningeal cells was accompanied by 1) the restitution of the normal morphology of the basement membrane, 2) the reappearance of neuronal and glial cells below the pial surface, and 3) the formation of fragments of the infrapyramidal blade which later developed a normal appearing lamination.(ABSTRACT TRUNCATED AT 400 WORDS)

A novel antineuronal antibody in serum and CSF of a patient with motor neuron disease

A patient with motor neuron disease and tonic pupil who had an antinuclear antibody (Ab) in the serum and oligoclonal pattern in IgG in the CSF is described. Sera and CSF from this patient and controls (37 sera and 30 CSF) were screened for an antineuronal Ab using immunoblotting. Only the serum and CSF from this patient contained an Ab to a 70-kD protein in the human spinal cord but not in the human muscle or cerebellar cortex. This patient's serum immunohistochemically stained human and Japanese monkey anterior horn cells but not Japanese monkey dorsal root ganglion.

Cerebellar cortical degeneration in association with small-cell carcinoma of the oesophagus

We report the association of paraneoplastic cerebellar cortical degeneration with small-cell oesophageal carcinoma in a 60-year-old woman and describe the histopathological findings. We believe this to be the first report of such an occurrence. The cytoplasmic antigen PGP 9.5, which is strongly expressed in cerebellar Purkinje cells, was identified immunohistologically in the primary tumour and immunoglobulin demonstrated on Purkinje cells. These findings support an immunological pathogenesis for this condition and suggest that it is mediated by antibodies directed against tumour antigen which cross-react with Purkinje cells.

Cytological investigations on the cerebellar cortex of sudden infant death victims

The study was based on the hypothesis that cerebellar hypoxia may play a role in sudden infant death syndrome resulting in morphological changes of the cerebellar cortex, especially with respect to Purkinje cell density. In the morphological evaluation of the Purkinje cell layer, special consideration was additionally given to secondary alterations (i.e., macrophage and/or astrocyte reaction). A total of 12 sudden infant death syndrome cases were compared with an age- and sex-matched control group. The Purkinje cell density was evaluated by determining the number of these cells per surface unit on parasagittal sections in both hemispheres. The myelomonocytic and glial reaction was demonstrated by immunohistochemical methods using lysozyme as leukocyte and macrophage markers and glial fibrillary acidic protein as an astrocyte marker. Qualitatively, no alterations resembling a macrophage or glial cell reaction were detected in sudden infant death syndrome. No differences between the right and left cerebellar hemisphere could be established in the victims of sudden infant death syndrome nor in the controls. The number of Purkinje cells per 0.352 mm2 cortex was higher in the younger victims of sudden infant death (younger than 45 weeks of gestation) than in all matched controls. A statistically significant difference in Purkinje cell density, however, could not be established, and, especially, no indications of hypoxia were observed in the cerebellar cortex.

Monoclonal antibodies reveal the global organization of the cerebellar cortex

Electrophysiological mapping of the rat cerebellar cortex has revealed an elaborate functional somatotopy that tract tracing procedures have shown to correlate with specific patterns of afferent and efferent connectivity that encompass the cerebellum as a whole. In contrast, most anatomical and biochemical procedures suggest that the cerebellar cortex is remarkably uniform. To unmask covert molecular heterogeneity underlying the functional map, it is appropriate to use monoclonal antibody technology to search for antigenic epitopes whose cerebellar distribution reflects or encodes the positional information. Given that no preconditions can be set on the biochemical nature of the putative epitopes, a shotgun approach to immunization and screening is required. The construction of monoclonal antibodies and screening for specificities that reveal positional information is discussed with examples from an anti-cerebellar antibody library.

A Mab to a unique cerebellar neuron generated by immunosuppression and rapid immunization

The cerebellar cortex is perhaps the best characterized structure in the mammalian central nervous system. Although the major cerebellar cell classes are well known, a new class of cerebellar cortical neuron has now been identified with a monoclonal antibody (Mab) generated by a procedure for rapid immunization and selective immunosuppression of antibody responses. This procedure generates a high frequency of immunoglobulin G-class antibodies of desired specificity, and has allowed the generation of two antibodies that recognize subsets of cerebellar cortical neurons. One of these antibodies defines a previously unrecognized class of cerebellar neuron. The distribution and antigenic characteristics of this neuron suggest that it has a distinct role in cerebellar circuitry.

Biochemical and functional characterization of a novel neuron-glia adhesion molecule that is involved in neuronal migration

Adhesion molecule on glia (AMOG) is a novel neural cell adhesion molecule that mediates neuron-astrocyte interaction in vitro. In situ AMOG is expressed in the cerebellum by glial cells at the critical developmental stages of granule neuron migration. Granule neuron migration that is guided by surface contacts between migrating neurons and astroglial processes is inhibited by monoclonal AMOG antibody, probably by disturbing neuron-glia adhesion. AMOG is an integral cell surface glycoprotein of 45-50-kD molecular weight with a carbohydrate content of at least 30%. It does not belong to the L2/HNK-1 family of neural cell adhesion molecules but expresses another carbohydrate epitope that is shared with the adhesion molecules L1 and myelin-associated glycoprotein, but is not present on N-CAM or J1.

Antigenic map of the rat cerebellar cortex: the distribution of parasagittal bands as revealed by monoclonal anti-Purkinje cell antibody mabQ113

Both anatomical and physiological mapping methods have revealed that the mammalian cerebellar cortex consists of a family of parasagittal bands of cells, each band with its own pattern of afferent and efferent axons. Monoclonal antibody mabQ113 recognizes an unknown polypeptide antigen that is confined to a subset of rat cerebellar Purkinje cells. Immunoreactive cells are arranged into parasagittal bands extending throughout the vermis and hemispheres. Expression of the Q113 epitope by individual Purkinje cells may not be all-or-nothing, since the bands tend to be more strongly stained in the vermis than the hemispheres. The band display is symmetrical about the midline and reproducible from individual to individual. Whole-mount immunocytochemistry and serial reconstruction reveal a median band of mabQ113+ Purkinje cells adjacent to the midline (P1+) and six other positive bands disposed symmetrically at either side (P2+ to P7+). Bands are distinct throughout most of the cortex but tend to fuse ventrally and caudally. There are two sources of interindividual differences. Firstly, most animals express supernumerary "satellite" bands in the vermis. Satellite bands are usually only one cell wide, are not bilaterally symmetrical, and differ in position and number from individual to individual. Secondly, the precise position of an individual band can differ, perhaps according to the variable cortical lobulation, for example, the position of P4+ in lobules VIII/IX and P6+ in lobule VII. While a scheme of parasagittal bands is a good description of the vermian organization, the distribution of mabQ113+ and mabQ113- Purkinje cells in the hemispheres may be better described as a checkerboard of antigenic patches.

Localization of Thy-1 expression during postnatal development of the mouse cerebellar cortex

Thy-1 is a cell membrane differentiation antigen with a restricted distribution in murine tissues. In both mice and rats the antigen is widely expressed in the CNS, while in the neonatal cerebellum it is expressed at very low levels. We have devised a protocol of immersion fixation by freeze-substitution that preserves both antigenicity and tissue morphology. We have stained freeze-substituted tissue sections of developing mouse cerebella with monoclonal anti-Thy-1. Thy-1 is faintly detectable at birth in Purkinje cells and in the molecular layer. The intensity in these two sites increases to a maximum at day 9; this subsequently decreases in the Purkinje cell cytoplasm until most are negative by day 21, but persists in the molecular layer into adulthood. Thy-1 is not detectable in the external granular layer and is only detectable in the glomeruli of the internal granular layer. Ascending fibre tracts are positive from day 5 onwards. The chronologic and anatomic expressions of Thy-1 are compatible with a role of Thy-1 in the generation and maintenance of synapses.

Immunocytochemical binding of serum IgG from a patient with oat cell tumor and paraneoplastic motoneuron disease to normal human cerebral cortex and molecular layer of the cerebellum

Serum from a patient with oat cell (OC) tumor and paraneoplastic upper and lower motoneuron syndrome showed binding of IgG but not IgM to normal human cerebral cortex (CC), molecular (M), and Purkinje (P) cell layers of the cerebellum, anterior horn cells (AHC), and dorsal root ganglia (DRG). There was no binding to glial and granular cells, white matter, peripheral nerve, or OC. Sera from three patients with OC tumor without neurologic deficit, three patients with non-OC lung cancer and peripheral neuropathy, and five healthy subjects were used as controls. While none of the control sera showed binding to the CC or M layer, the three controls with OC showed 50% reactivity with AHC, and other controls showed weak staining of PC, AHC, or DRG. Absorption of the patient's serum with cerebral or cerebellar tissue, but not with liver or spinal cord, resulted in elimination of the immunostaining. Staining of the CC and M layer could not be blocked by a monoclonal IgG to a glioma cell line, but partial blocking occurred by preincubating the tissue with monoclonal IgG (MF 491) to gastric carcinoma and cross-reacting with OC and several neural elements. The results suggest specific binding of the patient serum IgG to the CC and M layer; however, the relationship of this antibody to the pathogenesis of the paraneoplastic syndrome remains elusive.

Monoclonal antibodies reveal sagittal banding in the rodent cerebellar cortex

We have produced two monoclonal antibodies against polypeptide-associated antigens of developing rat cerebellum. One antibody recognizes an antigen associated with synaptic vesicles and another binds to a polypeptide which is restricted to the cytoplasm of a subset of cerebellar Purkinje cells. Both antibodies reveal the biochemical differentiation of the rodent cerebellar cortex into antigenically distinct sagittal zones.

Sites in myelin basic protein that react with monoclonal antibodies

The epitopes (antigenic sites) for seven monoclonal antibodies (MAbs) evoked in rats or mice by guinea pig or monkey myelin basic protein (BP) have been located in four different sequences of the BPs extracted from various species. Six of the MAbs were evoked by guinea pig BP. (1) One epitope, possibly a pair, is included within residues 1-14 of all BPs tested and reacts with two rat IgG MAbs. (2) A definite pair of overlapping epitopes includes the central Phe91-Phe92 sequence. One epitope is contained entirely within sequence 90-99 and reacts with a rat IgG MAb. The substitution of Ser in chicken BP for Thr97 destroys this epitope. The other epitope appears to include residues on the amino side of Phe44 and even of His32 and suggests some tertiary structure in BP. This epitope reacts with a mouse IgM MAb that does not recognize the chicken substitution. (3) The third epitope lies within residues 114-121, specifically including Trp118, and reacts with a rat IgG MAb. A cross-reacting epitope probably includes residues 44-45 in certain species (guinea pig and bovine but not rabbit). (4) Another pair of epitopes is located within residues 131-140 but is severely species-restricted. This region in guinea pig BP evoked a species-specific mouse IgM MAb. The same region in monkey BP evoked the seventh MAb, a mouse IgG, which reacts with human, chimpanzee, monkey, bovine, and rat-18.5 kDa BPs and to a lesser extent rabbit BP but not with guinea pig, pig, or chicken BPs. Some tertiary structure in guinea pig BP is also suggested by the reactivities with the IgM MAb. All of the MAbs react with myelin in histologic preparations, but the optimum method of preparation of the tissue varies with each.

Developmental changes of chick cerebellar cortex revealed by monoclonal antibodies

Immunohistochemistry studies of the embryonic and newly hatched chick cerebellum were performed with 13 monoclonal antibodies (MAbs) raised against the embryonic chick optic nerve and a MAb which binds to cell nuclei. Neural MAbs differentially stained Purkinje cells, the external granular layer, molecular layer, internal granular layer, climbing fibers, basket cell axons, Bergmann glia and Ramón y Cajal's ansiform fibers. At the different developmental stages each component responded to MAbs differently. For example, staining of Purkinje cells with MAbs 23C10, 82E10 and 94C2 appeared on day 11 of incubation and disappeared sequentially after day 18. These results reveal molecular heterogeneity not only in cerebellar neurons but also at various developmental stages.

Monoclonal antibody cross-reactions between Drosophila and human brain

A panel of 146 monoclonal antibodies (MAbs), obtained with Drosophila melanogaster tissue as primary immunogen, was tested for cross-reactivity with the human central nervous system. Sites examined included spinal cord, cerebellum, hippocampus, and optic nerve. Nonnervous tissues tested were liver and lymph node. Approximately half of the antibodies reacted with one or more sites in the human central nervous system, identifying regional, cell class, and subcellular antigens. Some recognized neuronal, glial, or axonal subsets. Immunoblot analysis revealed that some antibodies reacted with similar antigen patterns in both species.

A longitudinal band-pattern for the monoclonal human granulocyte antibody B4,3 in the cerebellar external granular layer of the immature rabbit

The monoclonal human granulocyte antibody B4,3 shows reactivity with structures in the external granular layer of the developing rabbit cerebellum. This reactivity is first observed at post-conceptional day 19-20 and disappears at postnatal day 5-6. The reactivity in the immature rabbit cerebellum is distributed in a longitudinal pattern of bands positive and negative for this monoclonal antibody.

[Myelinotoxic activity of sera from animals with experimental allergic encephalomyelitis in organotypic cultures of the rat cerebellum at different stages of differentiation]

Radiometry was used to assay myelinization and demyelinization in organotypic long-surviving cultures of the cerebellum from newborn rats. It was shown that serum from guinea-pigs with allergic encephalomyelitis suppresses by 45% the incorporation of labeled cholesterol into nerve tissue cells in the early periods of cultivation (within 10 days), i.e. before myelinization commencement. It also suppresses thymidine and cholesterol incorporation in the later periods of cultivation, i.e. in the last stages of differentiation, this suppression being increased twofold in the myelinized cultures of the nerve tissue. The effect of humoral factors of the sera from sick animals on the neuroglial cells in the course of nerve tissue differentiation in vitro is discussed.