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D M Marcus

Publications and source records attributed to D M Marcus.

At least 73 records · Page 4Linked to original sources
PubMed1991

Neuronal and glial properties of a murine transgenic retinoblastoma model.

Antigenic properties of a murine transgenic model for hereditary retinoblastoma, induced by a chimeric gene coding for Simian virus 40 large T antigen, an oncogene that inactivates the retinoblastoma susceptibility gene product, were studied by immunohistochemistry. All transgenic mice develop bilateral intraocular retinal tumors in the inner nuclear layer with Homer Wright-like rosettes, and one quarter develop midbrain tumors resembling trilateral retinoblastoma. Cell lines TE-1 and TM-1 were established from intraocular and metastatic tumors, respectively. Intraocular tumors reacted with antibodies to neuron-specific enolase and synaptophysin, while vimentin, glial fibrillary acidic, and S-100 proteins were detected only in reactive glia derived from adjacent retina. The midbrain tumors showed weak reactivity to synaptophysin, and they blended with reactive astrocytes positive for glial markers. The tumors were negative for cytokeratins. Finally both derived cell lines expressed synaptophysin and individual neurofilament triplet proteins in immunofluorescence and Western blotting, supporting their essentially neuronal nature. The antigenic profile resembles human retinoblastoma, but differences in morphology and antigen distribution suggest a more close relationship to neurons of the inner nuclear layer than to photoreceptor cells.

Animals↗
PubMed1991

Primitive neuroectodermal tumor of the midbrain in a murine model of retinoblastoma.

The first heritable model of retinoblastoma was established by retina-specific expression of simian virus 40 T-antigen (SV40 T-ag) in transgenic mice. Bilateral, multifocal ocular tumors were observed in 100% of transgene-bearing mice. Central nervous system neoplasms occurred at a lower rate (27%) and represented the murine counterpart of human trilateral retinoblastoma. The authors characterized the transgenic brain tumors and found them to be primitive neuroectodermal tumors (PNET) of the midbrain. Murine brain tumors do not involve the pineal gland and most closely resemble undifferentiated suprasellar or parasellar tumors occasionally observed in human trilateral retinoblastoma. The murine malignancies arose from the subependymal cells of the cerebral aqueduct. Immunohistochemical and ultrastructural examination revealed that the transgenic brain tumors were undifferentiated and lacked all antigens associated with normal murine neuronal, glial, and ependymal cells.

Animals↗
PubMed1990

The value of nucleolar organizer regions in uveal melanoma. The Collaborative Ocular Melanoma Study Group.

Silver staining of nucleolar organizer regions is an objective method for evaluating the malignancy of a variety of tumors. We studied 126 ciliochoroidal melanomas, three coincidental nevi that occurred in eyes with melanomas, and one magnocellular nevus collected from the Collaborative Ocular Melanoma Study to determine the effectiveness of the silver-stained nucleolar organizer region technique in assessing the malignant potential of these tumors. Malignant lesions demonstrated higher mean silver-stained nucleolar organizer region counts (4.347) than benign nevi (1.855) (P less than or equal to .0001). Among malignant melanomas, mixed-cell melanomas had slightly higher counts than spindle-cell melanomas (P less than or equal to .0001), but this difference was not important clinically. Results were also compared to other histopathologic variables, which disclosed correlation of silver-stained nucleolar organizer regions with mitoses and tumor size. Comparison with computerized cytomorphometric analyses of prognosis also disclosed significant correlation. This technique may prove to be a useful adjunct in the assessment of malignancy and treatment response of uveal melanomas.

Cell Count↗
PubMed1990

Interferon-gamma alters expression of endothelial cell-surface glycosphingolipids.

Our previous work on human endothelial cell (EC) glycosphingolipids (GSLs) demonstrated that these cells contain a large diversity of GSLs, predominantly with lacto core structures. In order to evaluate the role of GSLs as EC antigens and receptors, we investigated their cell-surface expression on confluent EC monolayers and ECs activated by interferon-gamma (IFN-gamma) and interleukin-1 (IL-1). IFN-gamma activation of endothelial cells resulted in a small change in GSL composition, but greatly increased surface expression of gangliosides and decreased surface expression of neutral GSLs. In particular, surface expression of the major neutral GSL, globoside, decreased three- to fourfold as measured both by galactose oxidase labeling and by binding of the anti-globoside monoclonal antibody 9G7. IFN-gamma did not significantly alter the total cell content of globoside, as measured by metabolic labeling, but rather altered the ratio of accessible cell surface to intracellular globoside. Two mechanisms appear to contribute to the decreased cell-surface globoside expression. IFN-gamma treatment increased the relative proportion of intracellular globoside which is associated with the cell cytoskeleton. IFN-gamma treatment also caused more of the cell-surface globoside to be inaccessible to antibody, and both neuraminidase and trypsin treatment of the cells increased globoside accessibility. IL-1 treatment increased total cell GSL content, but did not alter GSL composition or cell-surface binding by six anti-carbohydrate antibodies. The specific modulation of cell-surface GSLs by IFN-gamma suggests that GSLs may play a role in the altered adhesive and receptor activities of IFN-gamma-activated ECs.

Antibodies↗
PubMed1990

Retinoblastoma in transgenic mice.

Retinoblastoma, a malignancy of the eye occurring in young children, has been widely studied as a model for genetic predisposition to cancer. This disease is caused by mutations in both alleles of an anti-oncogene (the retinoblastoma gene, Rb) that inactivate or eliminate the Rb encoded protein, p105Rb (refs 1 and 2). Here we report that expression of a viral oncogene, the simian virus 40 T antigen, in the retina of transgenic mice produces heritable ocular tumours with histological, ultrastructural and immunohistochemical features identical to those of human retinoblastoma. Furthermore, we demonstrate a specific association between p105Rb and T antigen in mouse retinoblastoma tumour cells. Thus, the occurrence of these tumours is in vivo evidence for oncogenesis due to the ocular-specific expression of an Rb-binding oncoprotein that can functionally inactivate the Rb protein. As an animal model for heritable retinoblastoma, these mice should allow the study of the ontogeny, pathogenesis and treatment of this malignant disease.

Animals↗
PubMed1990

Anophthalmia in the focal dermal hypoplasia syndrome.

We examined an orbital exenteration specimen from an anophthalmic patient with focal dermal hypoplasia. Eyelid angiofibromas were evident and immunoperoxidase studies for human papilloma virus were negative. Orbital tissue contained a ductal cyst, chronic inflammation of the lacrimal duct and sac, rudimentary conjunctival fornices, lacrimal gland, striated muscle, and adipose tissue. Microscopic examination revealed a posteriorly located cystic structure with uveal and lens remnants. Neuroectodermal structures consistent with retina, optic nerve, or meninges were not observed, thus representing true anophthalmia. These findings remain as the only histopathologic description of ocular tissues in patients with focal dermal hypoplasia.

Adult↗
PubMed1990

Ligneous conjunctivitis with ear involvement.

We report the association of ligneous conjunctivitis with middle-ear and tympanic membrane involvement in two children. Eye and ear specimens revealed histopathologic and ultrastructural findings consistent with ligneous conjunctivitis, characterized by an amorphous, eosinophilic material with acute and chronic nongranulomatous inflammation. Ear specimens demonstrated granulation tissue along with the above features. Conjunctival and ear lesions from these patients were studied histochemically, immunohistochemically, and ultrastructurally. Our studies demonstrate fibrin and albumin deposition as a common feature in all lesions. Deposition of other components, such as mucopolysaccharides, amyloid, immunoglobulins, and mast cells, were, however, variable. The diversified nature of these lesions, together with the association of eye and ear disease, substantiates the existence of an underlying systemic disorder of unknown cause.

Amyloid↗
PubMed1990

A transgenic mouse model for trilateral retinoblastoma.

We present a murine model of trilateral retinoblastoma. Ocular retinoblastoma and central nervous system tumors are observed in a line of mice formed by the transgenic expression of SV40 T-antigen. An oncogenic protein known to bind to the retinoblastoma gene product (p105-Rb) is specifically expressed within retinal cells in this model. All animals that carry this genetic alteration develop multifocal retinal tumors. Midbrain tumors are observed in 15% of ocular tumor-bearing animals, and these arise ventral to the cerebral aqueduct at the level of the pineal gland. Both ocular and central nervous system neoplasms are heritable in heterozygous offspring through 10 sequential generations of breeding. Retinal tumors display the gross appearance, invasive properties, light and electron microscopic features, and immunohistochemical staining characteristics of human retinoblastoma. The light and electron microscopic characteristics as well as immunocytochemical features of undifferentiated midline central nervous system neoplasms further correlate with human trilateral retinoblastoma. We postulate an alternative mechanism of retinoblastoma tumorigenesis that involves functional inactivation of retinoblastoma protein locally in the face of an intact retinoblastoma gene locus.

Animals↗
PubMed1990

Measurement and clinical importance of antibodies to glycosphingolipids.

Measurement of antibodies against gangliosides and other glycosphingolipids (GSLs) is technically demanding because of their low affinity for antigen. A recent workshop, in which twelve laboratories received a coded panel of sera containing anti-GM1 antibodies, demonstrated that the immunoassays varied widely in sensitivity and in criteria employed for a positive test. The fine specificity of anti-GSL antibodies should be characterized by analyzing their reactivity with a panel of GSLs with related structures. High-titer monoclonal IgM antibodies against gangliosides and sulfated carbohydrates appear to cause neuropathy in some patients. Low-titer polyclonal antibodies against gangliosides occur frequently in a variety of diseases, including autoimmune diseases without neurological symptoms. It is unclear whether these polyclonal antibodies are a primary manifestation or a consequence of the disease, and their clinical importance is uncertain at present.

Autoantibodies↗
PubMed1990

Heavy and light chain sequences of four monoclonal antibodies that bind galactosylgloboside (GalGb4).

We recently described IgM monoclonal antibodies directed against the glycospingolipid galactosylgloboside (GalGb4; Marcus, M. D. et al., Arch. Biochem. Biophys, 1988.262: 620). We now present the nucleotide and deduced amino acid sequences of the heavy and light chains of these antibodies. The antibodies were generated in a single fusion, their heavy as well as their light chains are almost identical, and they appear to be clonally related. The light chains were encoded by J kappa 5 and a V kappa gene belonging to the Ox1 family, but they are only 93% homologous to the most closely related germ-line gene, and they are probably encoded by a germ-line gene that has not yet been identified. The heavy chains were all encoded by VH441 and JH2, and have identical N segments. The VH441 germ-line gene encodes a potential glycosylation site at Asn58 in the complementarity-determining region 2. This site, which has been retained in all VH441-encoded monoclonal antibodies sequenced previously, was mutated out by a single base change in all four anti-GalGb4 antibodies.

Amino Acid Sequence↗
PubMed1990

Histopathologic verification of Verhoeff's 1918 irradiation cure of retinoblastoma.

The authors studied an eye obtained postmortem from the first patient with a successfully irradiated retinoblastoma. This patient, first treated by Verhoeff in 1917, had been followed for 71 years. Ophthalmoscopy disclosed a depressed chorioretinal scar, approximately 3 disc diameters (DD) in size, with baring of the sclera temporal to the macula. This case is historically significant, in that Verhoeff and Reese debated as to whether this tumor regressed spontaneously or secondary to irradiation. Results of histopathologic, immunohistochemical, and ultrastructural examination showed a chorioretinal, neuroglial scar without evidence of calcification, necrotic tumor cells, or residual retinoblastoma. The authors discuss the clinical and histopathologic findings in spontaneously regressed retinoblastoma, retinoma/retinocytoma, and irradiated retinoblastoma. They believe that Verhoeff was correct in his belief that x-ray therapy had cured this patient.

Aged↗
PubMed1989

Human IgM monoclonal proteins that bind 3-fucosyllactosamine, asialo-GM1, and GM1.

Analysis of monoclonal human Ig that occur in association with lymphoproliferative diseases has provided valuable information about antibody structure and idiotypes. We analyzed 940 human sera that contained monoclonal IgM proteins for their ability to bind to four carbohydrate epitopes. Ten sera bound asialo-GM1, five of these sera also bound GM1, 10 bound to 3-fucosyllactosamine (3-FL), and one each bound to levan and galactan. Although the antibody activity in each serum was associated with a single L chain isotype, both kappa and lambda isotypes were represented among the proteins that bound to asialo-GM1 and to 3-FL. Some antibodies against asialo-GM1 were highly specific for this compound, whereas others cross-reacted with the structurally related gangliosides GM1 and GD1b. The antibodies to asialo-GM1 also varied considerably in their ability to lyse liposomes that contain asialo GM1. An association of IgM mAb against gangliosides with peripheral neuropathies has been reported recently, but only one of five patients whose antibodies reacted with GM1 ganglioside had a neuropathy. The antibodies that bound 3-FL exhibited narrower specificity, and less than 10% cross reactivity was noted with structurally related carbohydrates. The frequency of monoclonal proteins that bound 3-FL and asialo-GM1, approximately 1:100 sera for each specificity, was surprisingly high in view of the fact that both of these epitopes are expressed in human tissues. We suggest that these antibodies may be poly-specific and/or that the subset of B lymphocytes that synthesizes these anti-carbohydrate antibodies undergoes malignant transformation more frequently than other B lymphocytes.

Antibodies, Monoclonal↗
PubMed1989

Antibodies against ganglioside GT3 in the sera of patients with type I diabetes mellitus.

Clinical and experimental data support the concept that type I diabetes mellitus results from autoimmune destruction of pancreatic beta cells. Although both proteins and glycolipids are targets of anti-islet cell antibodies, the Ag have not been purified or characterized. Previously, we observed that rat insulinoma (RIN) cell lines varied in their reactivity with both human antibodies and murine mAb A2B5, which binds to polysialo gangliosides. To determine the chemical basis of the varied immunoreactivity, we analyzed the glycosphingolipids of 5 RIN lines. Glycolipids bound by two mAb and by antibodies in the sera of type I diabetics were identified. The more immunoreactive RIN lines contained a much higher content of gangliosides and a higher proportion of complex gangliosides. The major gangliosides were GM3, GD3, and GT3. By high performance TLC immunostaining, we demonstrated that A2B5 and R2D6, an anti-beta cell murine mAb, bound most strongly to ganglioside GT3. The binding of human sera to gangliosides was analyzed by an ELISA assay. Although both normal and diabetic sera contained antibodies to various glycolipids, binding to GT3 was significantly elevated in 31 new-onset type I diabetics (p less than 0.001). The presence of the GT3 trisialosyl epitope on human islet cells was shown by immunofluorescent staining by both R2D6 and A2B5. These findings support previous suggestions that gangliosides play an important role in the immunopathology of type I diabetes, and identify for the first time a specific ganglioside Ag that is the target for autoantibodies in a subset of diabetic patients.

Adolescent↗
PubMed1989

Expression of a cross-reactive idiotope on naturally occurring murine antibodies against 3-fucosyllactosamine, levan, and dextran.

We recently identified a cross-reactive Id (6C4) that is expressed on the H chain of many BALB/c mAb against the 3-fucosyllactosamine (3-FL) determinant, Gal(beta 1-4) (Fuc(alpha 1-3] GlcNAc-R. The VH segments of seven mAb that we recently sequenced are encoded by VH441, which also encodes VH segments of antibodies against galactan, levan, and dextran. To analyze the expression of the 6C4 Id on naturally occurring anti-carbohydrate antibodies, we isolated 6C4+ antibodies by affinity chromatography from pools of normal BALB/c serum. Approximately 20 to 30% of antibodies against 3-FL and levan, and all antibodies against dextran, were removed from the sera by passage over a column containing mAb 6C4. Absorption of the eluate with 3-FL beads removed anti-3-FL antibodies but not anti-dextran or anti-levan. The expression of a cross-reactive Id on naturally occurring antibodies against several carbohydrate Ag suggests that these antibodies may participate in an Id network. We also reported previously that BALB/c mice have naturally occurring anti-3-FL antibodies and respond well to immunization against this determinant, whereas C57BL/6 mice do neither. To examine the role of the Igh-C allotype in the regulation of the anti-3-FL response, we studied congenic strains of BALB/c and C57BL/6 mice. Both congenic strains produced anti-3-FL antibodies in response to immunization, but only C.B-20 mice exhibited naturally occurring antibodies. These data suggest that the naturally occurring and elicited antibody responses against 3-FL are differentially regulated.

Animals↗
PubMed1989

Restricted usage of VH and V kappa genes by murine monoclonal antibodies against 3-fucosyllactosamine.

We are studying the structure and regulation of murine antibodies against the 3-fucosyllactosamine antigenic determinant. Analysis of the sequences of seven BALB/c IgM, kappa monoclonal antibodies (mAb), obtained from four fusions, indicates that these antibodies exhibit restriction in their usage of VH and VL genes. Based on a combination of mRNA sequences and Southern filter hybridization data, all seven light chains are encoded by V kappa 24B and J kappa 1 gene segments. Complete mRNA sequences of the heavy chains revealed that all seven mAb are encoded by VH441, six antibodies are encoded by JH4 and one uses a JH3 gene segment. The VH441 gene segment and all seven mAb contain a potential glycosylation site at Asn 58 in complementarity-determining region (CDR)2. In contrast to the similarity of the VH regions, the heavy chain CDR3 segments exhibit considerable heterogeneity. They are encoded by three D segments, they vary in length from 7-9 amino acids and display differences in their deduced amino acid sequences. The VH441 gene segment also encodes antibodies against four other carbohydrate antigens, levan, galactan, dextran and galactosyl globoside. The use of a single gene segment to encode antibodies against five different antigens suggests that the domain encoded by VH441 might be particularly well adapted for forming sites that bind carbohydrate determinants. Glycosylation of CDR2 might contribute to the unique properties of this VH domain.

Amino Acid Sequence↗
PubMed1989

Serum immunoglobulin levels and naturally occurring antibodies against carbohydrate antigens in germ-free BALB/c mice fed chemically defined ultrafiltered diet.

This study investigates the influence of exogenous antigenic stimulation on the serum immunoglobulin levels and the levels of circulating natural antibodies against carbohydrate antigens. Thus, BALB/c mice, raised in a germ-free environment and fed a chemically defined, ultrafiltered diet (GF-CD), were employed. These mice had normal serum IgM levels, but IgG and IgA levels were approximately 5% of conventionally reared littermates. The concentrations of all four IgG isotypes were equally low. The variable part of the heavy chains of naturally occurring BALB/c antibodies against a number of carbohydrate antigens, including 3-fucosyllactosamine (3-FL), levan and dextran, are encoded by VH441, and these antibodies express cross-reactive idiotopes recognized by the monoclonal antibodies 6C4 and 6B1. Antibodies against levan and dextran were lower in GF-CD than in conventional mice, but levels of anti-3FL antibodies, and 6C4 and 6B1 idiotopes, were comparable to those in conventional animals. Peptidoglycan polysaccharide complexes (PPC) are carbohydrate antigens of bacterial origin, like levan and galactan. Naturally occurring antibodies against PPC were found in the serum of conventional mice, but were severely reduced in GF-CD mice. The results indicate that most naturally occurring antibodies against carbohydrate antigens of bacterial origin found in conventional mice are caused by exogenous stimulation.

Animals↗
PubMed1989

Lack of suppression by gangliosides of humoral or cellular immunity in vivo.

Gangliosides inhibit the proliferative responses of murine and human lymphocytes in vitro, and it has been suggested that they are immunosuppressive in vivo, although no in vivo studies have been performed. In view of the use of gangliosides to treat patients with a variety of neurological disorders, experiments were undertaken to evaluate the possible immunomodulatory effects of gangliosides in vivo. BALB/c mice were injected 5 days a week with buffer, mixed brain gangliosides, or GM1 ganglioside at dosage levels of 30 mg/kg, 60 mg/kg or 90 mg/kg. After 30 days of treatment, the mice were immunized with keyhole limpet hemocyanin or pneumococcal type III polysaccharide and the ganglioside treatment was continued. No differences between treated and control groups were noted in either the magnitude or duration of the antibody response. No differences between groups were noted in the proliferative responses of splenic mononuclear cells to concanavalin A or allogeneic antigens after 9-10 weeks of treatment, nor in the generation of cytotoxic effector cells after 90 days of treatment. Thus, despite the well-documented immunosuppressive effects of gangliosides in vitro, no evidence for a suppressive effect on humoral or cellular immunity in vivo was obtained in these studies.

Animals↗