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Biomedical subjects

O Abramsky

Publications and source records attributed to O Abramsky.

At least 73 records · Page 4Linked to original sources
PubMed1994

Orally administered myelin basic protein in neonates primes for immune responses and enhances experimental autoimmune encephalomyelitis in adult animals.

Antigen-driven tolerance is an effective method for suppression of autoimmune diseases. Adult animals can be tolerized against the induction of experimental autoimmune encephalomyelitis (EAE) by both oral and parenteral administration of myelin basic protein (MBP). We have found that in contrast to previous studies of neonatal tolerance in which parenterally administered autoantigens induced tolerance, the oral administration of MBP in neonatal rats did not result in tolerization to MBP, but instead, primed for immunologic responses. Proliferative responses to MBP and its encephalitogenic epitope were present in animals fed with MBP as neonates and co-culture of encephalitogenic T cells with cells from neonatal rats fed with MBP were associated with enhanced MBP responses rather than the suppression observed with cells from adult rats fed with MBP. Furthermore, neonates fed with MBP and immunized 6-8 weeks later with MBP in adjuvant to induce EAE revealed enhancement of disease severity, and were not protected from a second attack upon active reinduction of EAE. Subcutaneous injection of soluble MBP into neonates had no effect on EAE induction as adults, whereas intraperitoneal injection of MBP in neonates was associated with marked suppression of disease in adults. Suppression of EAE began to appear in animals fed with MBP at 4 weeks of age, and was similar to oral tolerance in adult animals when animals were fed at 6 weeks of age. These results suggest that immaturity of the immunoregulatory network associated with oral tolerance and sensitization to autoantigens via the gut in the neonatal period may contribute to the pathogenesis of autoimmune diseases.

Administration, Oral↗
PubMed1994

Multiple sclerosis: genetic versus environmental aetiology: epidemiology in Israel updated.

The incidence and prevalence of multiple sclerosis (MS) were compared, controlling for age, in native-born Israelis of different origins and in immigrants to Israel. This comparison was carried out in two populations, countrywide and in Jerusalem. In the countrywide population, ascertainment was based mainly on hospitalizations; it included 252 patients who were native-born and 150 who had immigrated from Africa-Asia (AA immigrants). The 89 MS patients of Jerusalem also included patients diagnosed in outpatient clinics. In native-born Israelis whose father was born in Europe-America (I-EA), the incidence and prevalence of MS were found to be as high as or even higher than that found previously in immigrants from Europe-America. Among native-born Israelis whose father was born in Africa or Asia (I-AA), the yearly age-adjusted incidence and prevalence rates were found to be 1.4- to 1.8-fold higher than among AA immigrants, pointing to environmental factors. The incidence and prevalence rates in the I-EA were 1.2- to 1.6-fold higher than in the I-AA, pointing to genetic factors. These results seem to point to both environmental and genetic factors in the aetiology of MS. Further research is needed, however, to disentangle the genetic factors from possible environmental differences in the two ethnic groups.

Adolescent↗
PubMed1994

Immunomodulation of experimental autoimmune myasthenia gravis with linomide.

Linomide, a synthetic immunomodulator, increases natural killer (NK) activity and markedly activates several lymphocyte populations in both experimental animals and humans. It has been shown to ameliorate the autoimmune manifestations of lupus-like disease in MRL/lpr mice and the clinical and pathological signs of acute and chronic-relapsing experimental autoimmune encephalomyelitis (EAE) in SJL/J mice. We examined the effect of linomide (100 mg/kg/day; administered in drinking water) on rabbits and rats with experimental autoimmune myasthenia gravis (EAMG). Following immunization with Torpedo acetylcholine receptor (AChR), all control rabbits developed clinical signs of severe weakness and exhibited a decrement of muscle action potential upon repetitive stimulation. In contrast, mild signs of weakness appeared in only two of five linomide-treated rabbits, with EMG borderline positive in one of them. Booster immunization with Torpedo AChR induced severe relapse and death in two EAMG control rabbits, whereas the two linomide-treated animals remained free of myasthenic symptoms. The serum level of antibodies against both Torpedo and rat AChR were markedly suppressed in the linomide-treated animals. Similar inhibition of clinical signs of EAMG was observed in the EAMG rat model. Furthermore, the in vitro proliferative response of lymph node cells to Torpedo AChR and the purified protein derivative of Mycobacterium tuberculosis was significantly lower in the linomide-treated EAMG rats than in the controls. Linomide may constitute a new immunomodulating agent for the treatment of myasthenia gravis.

Adjuvants, Immunologic↗
PubMed1994

Oral administration of the oxidant-scavenger N-acetyl-L-cysteine inhibits acute experimental autoimmune encephalomyelitis.

The prevention of acute experimental autoimmune encephalomyelitis (EAE) by N-acetyl-L-cysteine (NAC), a potent free radical scavenger, is described. Administrated ad libitum to SJL/J mice at a dosage of 0.2-2 mg/ml in drinking water from the day of the encephalitogenic injection, the agent significantly inhibited the induction of acute EAE. The improvement in clinical condition was dose-dependent. A complete protective effect required administration of the agent at an early stage. Examination of lymphocytes from NAC-treated EAE mice showed that at early stages (days 9 and 15) post encephalitogenic injection the anti-oxidant enhanced the specific lymphocyte proliferative response to the immunizing antigens. Examination of the mitogenic stimulation of lymphocytes from naive animals in the presence of NAC in vitro indicated that the scavenger enhanced the stimulative effect of LPS in a dose-dependent manner. The immunomodulative capacity of the anti-oxidant NAC suggests that free radicals are involved in the pathogenesis of acute EAE.

Acetylcysteine↗
PubMed1994

Inoculation of BCL1 lymphoma cells into CSJL/J F1 mice inhibits acute experimental autoimmune encephalomyelitis.

T cell vaccination, which protects rodents against experimental autoimmune encephalomyelitis (EAE), has been shown to induce anti-idiotypic response in the T cell compartment. CD5 B cells (B1 cells) are the main source of natural autoantibodies, and are often characterized by high idiotypic connectivity. In this study we examined the possibility that idiotypic connectivity in the B cell compartment may also play a role in the regulation of EAE. We inoculated CSJLF1 mice (H-2d,s) with a CD5 B cell line, the BCL1 lymphoma cells (H-2d), and subsequently induced EAE. The injection of as few as 1,000 BCL1 lymphoma cells significantly blocked the development of EAE. Injection of CD5-negative myeloma cells (SP2) had no effect on the pathogenesis of the disease. Unlike control animals, lymphocytes from BCL1 lymphoma-injected mice significantly proliferate in response to interleukin-5, a growth factor to CD5 B cells. The proliferative response of lymphocytes from BCL1 inoculated mice to mitogenic stimulation was rather unchanged, indicating that no general immunosuppression has been induced by inoculating BCLJ lymphoma. These experiments suggest that CD5 B cells may be involved in the regulation of EAE.

Acute Disease↗
PubMed1993

Treatment of chronic-relapsing experimental autoimmune encephalomyelitis with the synthetic immunomodulator linomide (quinoline-3-carboxamide).

Linomide is a synthetic immunomodulator that enhances natural killer cell activity and significantly activates several lymphocytic cell subpopulations in both experimental animals and humans. In this study we examined the effect of linomide (80 mg per kg per day in drinking water) on mice with chronic-relapsing experimental autoimmune encephalomyelitis (CR-EAE), a T-cell-mediated organ-specific autoimmune disease that resembles human multiple sclerosis. None of the mice (n = 17) that were treated with linomide from day 7 after disease induction developed any clinical or histopathological signs of CR-EAE, as compared to 19 of 20 untreated controls that were severely paralyzed and had extensive demyelinating lesions in the central nervous system. Linomide-treated animals were also resistant to an induced attack by a booster injection with a murine spinal cord homogenate. When administered to mice exhibiting severe clinical signs of paralysis, linomide inhibited both spontaneous and induced relapses. Linomide treatment protected mice from passively induced CR-EAE as well, when given from the day of injection with myelin-basic-protein-specific lymphocytes. Lymphocytes obtained from linomide-treated mice had a reduced in vitro proliferative response to the myelin basic protein and to the tuberculin purified protein derivative, whereas the mitogenic response to concanavalin A was not affected. Natural killer cell and lymphokine-activated killer cell activities were enhanced. These results suggest that linomide regulates autoimmunity in the absence of systemic immunosuppression. Since linomide is very well tolerated in experimental animals and humans, it might be used in the treatment of multiple sclerosis.

Adjuvants, Immunologic↗
PubMed1993

Stimulation of tumor necrosis factor-alpha production by mycoplasmas and inhibition by dexamethasone in cultured astrocytes.

Elevated levels of tumor necrosis factor-alpha (TNF alpha) and other cytokines and eicosanoids in the central nervous system (CNS) have been noted in several human neurologic diseases, including multiple sclerosis and AIDS dementia. Recently it was shown that glial cells, especially astrocytes, are a major source of cytokines and eicosanoids. In the present study we have shown that astrocytes derived from fetal rat brain triggered by mycoplasmas produce TNF alpha and prostaglandin E2 (PGE2). Addition of mycoplasma (Mycoplasma capricolum isolated from sheep and M. fermentans KL-4 from human) at a concentration of 1-50 micrograms protein/ml (2 x 10(7)-10(9) colony forming units/ml), as well as lipopolysaccharide (5 micrograms/ml), led to a 200-500-fold increase in TNF alpha and a 2.5-4.5-fold increase in PGE2 production. Preincubation of the cells with the synthetic glucocorticoid, dexamethasone (2 x 10(-5)-2 x 10(-8) M), as well as with the natural hormone, corticosterone, markedly inhibited the secretion of both TNF alpha and PGE2. Thus, mycoplasmas can be added to the wide variety of agents that stimulate glial cells to produce cytokines and eicosanoids, and may contribute to various CNS pathological manifestations. In addition, the ability of glucocorticoids to inhibit particularly the stimulated productions of TNF alpha and PGE2 may explain at least in part the therapeutic benefit of these agents in CNS inflammation and demyelination.

Animals↗
PubMed1993

Inhibition of acute, experimental autoimmune encephalomyelitis by the synthetic immunomodulator linomide.

Linomide (LS-2616, quinoline-3-carboxamide) is a synthetic immunomodulator that stimulates natural killer cell activity and activates several lymphocytic subpopulations in experimental animals and humans. In this study we determined the effect of oral treatment with linomide on the development of experimental autoimmune encephalomyelitis, an animal model for immune-mediated human demyelinating disorders. Experimental autoimmune encephalomyelitis was induced in SJL/J mice and in an outbred strain of rats (Sabra) by subcutaneous injection of spinal cord homogenate in adjuvant followed by inoculation with Bordetella pertussis. Linomide was administered in drinking water, at an estimated dose of 50 to 100 mg/kg/day. None of the linomide-treated mice (0/41) and Sabra rats (0/15) developed any clinical or pathological signs of experimental autoimmune encephalomyelitis, whereas almost all control animals (48/53 and 18/19, respectively) were severely paralyzed and 64.5% died from the disease. Lymphocytes obtained from linomide-treated animals had reduced in vitro proliferative responses to guinea pig myelin basic protein, proteolipid protein of the myelin, and tuberculin-purified protein derivative, unlike antigen-independent proliferation which was rather unaffected. Natural killer cell activity (tested by a cytotoxic assay on radiolabeled YAC-1 target cells) was significantly enhanced in mice treated with linomide. Our results indicate that modulation of the immune system with linomide leads to complete inhibition of experimental autoimmune encephalomyelitis in the absence of systemic immunosuppression. Linomide could therefore be of use in future clinical trials for the treatment of human autoimmune demyelinating disorders.

Adjuvants, Immunologic↗
PubMed1993

Natural and experimental transfer of anti-Pertussis antibodies confers resistance to experimental autoimmune encephalomyelitis.

Pregnant rats challenged with Bordetela Pertussis vaccine, with or without encephalitogenic antigen during pregnancy, transferred a resistance to induction of experimental autoimmune encephalomyelitis (EAE) to their offspring. Cross-fostering experiments showed that the protection against EAE is conferred during the lactation period through the transfer of anti pertussis antibodies in the milk. The degree of protection correlated with antibody levels. Passive transfer of these antibodies through intraperitoneal injection to naive adult rats also conferred the same degree of protection against EAE induction. It is suggested that such transfer of resistance and antibodies may serve as a model for the study of milk transmitted immunocompetent factors, as well as a model for the mechanisms involved in the resistance to EAE.

Aging↗
PubMed1993

Synthesis of antibodies against measles virus and myelin by in vitro stimulated B-cells derived from patients with subacute sclerosing panencephalitis.

Subacute sclerosing panencephalitis (SSPE) patients carry persistent measles virus infection in the brain. Furthermore, the blood lymphocytes contain viral RNA. Lymphocytes derived from 6 SSPE patients were stimulated with Epstein-Barr virus (EBV). Production of antibodies against measles virus of the IgG isotype was detected in the supernatants of cell cultures of all patients, regardless of the disease's activity, duration or interferon therapy. In contrast, only some of these cell cultures also produced antibodies against myelin.

Adolescent↗
PubMed1993

Prevention and reversal of adoptively transferred, chronic relapsing experimental autoimmune encephalomyelitis with a single high dose cytoreductive treatment followed by syngeneic bone marrow transplantation.

A chronic relapsing form of experimental autoimmune encephalomyelitis (CR-EAE) was induced in SJL/J mice by adoptive transfer of lymph node cells (LNC) sensitized to guinea pig myelin basic protein (GMBP). We examined the efficacy of high dose immunosuppressive regimens (cyclophosphamide [CY] 300 mg/kg or total body irradiation [TBI] 900 cGy) followed by syngeneic bone marrow transplantation (SBMT) in prevention and treatment of already established CR-EAE. Treatment with TBI and SBMT on day 5 after the induction of CR-EAE, just before the onset of clinical signs, completely inhibited the appearance of the paralytic signs. The same treatment, applied 4 d after the clinical onset of the disease, led to a significant regression of the paralytic signs and to a total inhibition of spontaneous relapses during a follow-up period of 2 mo. Challenge of mice with GMBP+CFA 78 d after the passive induction of CR-EAE induced a relapse of the disease 7 d later in almost all of the untreated mice; in contrast, the same challenge given to TBI+SBMT-treated mice caused a delayed relapse (30 d later) in only a minority (3/7) of the challenged mice. In vitro lymphocytic proliferative responses to GMBP and purified protein derivative were significantly lower in TBI/SBMT-treated mice before and after the GMBP challenge, although these mice were fully immunocompetent, as evidenced by their normal lymphocytic proliferation to concanavalin A (ConA) and the FACS analysis of their lymphocytic subpopulations. A similar beneficial therapeutic effect was observed in mice treated with CY followed by SBMT, after the onset of CR-EAE. Our results could support possible clinical applications of similar therapeutic strategies, involving acute immunosuppression followed by stem cell transplantation and retolerization of the reconstituting immune cells in life-threatening neurological and multisystemic autoimmune diseases.

Animals↗
PubMed1992

Prevention of experimental autoimmune encephalomyelitis and induction of tolerance with acute immunosuppression followed by syngeneic bone marrow transplantation.

Experimental autoimmune encephalomyelitis (EAE) is an inducible autoimmune disease widely used as a model of the acute/relapsing stage of multiple sclerosis. In the present study we examined the effect of acute immunosuppression induced by total body irradiation (TBI) (900 to 1100 centigray (cGy)) or by a single high dose of cyclophosphamide (CY) (300 mg/kg), followed by syngeneic bone marrow transplantation (SBMT), on the development of EAE in SJL/J mice. EAE was induced in SJL/J mice by immunization with spinal cord homogenate in adjuvant. Treatment with TBI (900 cGy) and SBMT on day 6 postimmunization caused a delayed onset and a marked reduction in the incidence and severity of EAE. A higher dose of irradiation (1100 cGy) or the administration of CY followed by SBMT completely abrogated the development of paralysis. None of the 21 mice treated with CY and SBMT, and only 1 of 7 mice treated with TBI (1100 cGy) and SBMT developed clinical signs of EAE during a period of 3 months. Furthermore, mice treated with CY and SBMT became resistant to rechallenge with the same encephalitogenic inoculum. In addition, the lymphocytes obtained from these mice did not proliferate in vitro in response to myelin basic protein or tuberculin-purified protein derivative, unlike lymphocytes from immunized but untreated animals. This absence of reactivity was not associated with alterations in the proportion of the L3T4 and Lyt-2 T-cell subsets nor with a loss in T cell competence as evidenced by the full response of lymphocytes to the T cell mitogen Con A and to a nonrelevant Ag (OVA). Our results indicate that the elimination of effector lymphocytes either by myeloablative doses of CY or ionizing irradiation followed by rescue with SBMT inhibits the development of the autoimmune process in EAE and leads to induction of tolerance to the immunizing Ag by newly developing lymphocytes. This approach of combining immunoablation and reconstitution with autologous bone marrow transplantation may be applicable in the treatment of life-threatening neurologic autoimmune diseases.

Animals↗
PubMed1992

Neurologic manifestations of progressive systemic sclerosis.

Neurologic involvement in progressive systemic sclerosis is considered uncommon. We retrospectively examined the prevalence and nature of neurologic complications in 50 patients with progressive systemic sclerosis. In 20 (40%), neurologic abnormalities were detected, with a total of 28 neurologic manifestations. All levels of the central and peripheral nervous system were affected: muscle (22%), peripheral nerve (18%), spinal cord (8%), and brain (6%). Of note were the presence of myelopathy in four patients and inclusion-body myositis in two. In 10 patients (20%), no definable cause of the neurologic dysfunction could be identified, apart from progressive systemic sclerosis. Thus, neurologic presentations of progressive systemic sclerosis are much more common than previously reported and may be due to direct involvement of the nervous system by a primary pathologic process in a significant number of patients.

Adult↗
PubMed1992

An association between multiple sclerosis and type I diabetes mellitus.

We report five patients who had multiple sclerosis (MS) associated with type I diabetes mellitus (TODM). Examination of the Israeli National Neurological Disease Register revealed the prevalence of TODM among 334 MS patients under the age of 30 years to be 8.98 per 1,000. This is significantly higher than the prevalence of TODM in the general population of Israel for the same age group, which is 0.095 per 1,000. MS and TODM share clinical, epidemiological and immunological features, and both diseases have a target site that is neuroectodermal in origin. The association between these two putative autoimmune diseases may suggest a similar pathogenetic mechanism.

Adolescent↗