Interaction of multiple sclerosis serum with liposomes containing ganglioside GM1

Liposome-Assisted Drug Delivery in the Treatment of Multiple Sclerosis

Multiple sclerosis (MS) is an immune-mediated demyelinating disease of the nervous system that leads to neurological dysfunctions and severe disabilities. It is worth noting that conventional pharmacotherapy is poorly selective and causes toxicity problems and several systemic side effects. Thus, there is a need to develop new approaches to this medical challenge. The use of nanocarriers for drug delivery represents a good strategy to overcome several issues such as high therapeutic drug doses with side effects, such as diarrhea, nausea, and abdominal pain, and drug degradation processes; in addition, nanocarriers can provide controlled and targeted drug release. This review describes the application of liposomes for the delivery of pharmaceutical actives to target MS. Firstly, MS is explained. Then, liposomes are described along with their preparation, characterization, and stability. The literature about the use of liposomes for the treatment of MS is then analyzed.

Increased circulating T cell reactivity to GM3 and GQ1b gangliosides in primary progressive multiple sclerosis

We have previously shown that patients with primary progressive multiple sclerosis (MS) have significantly elevated plasma levels of antibody to GM3 ganglioside compared to patients with relapsing-remitting MS, healthy subjects and patients with other neurological diseases. Anti-GM3 antibody levels were elevated also in patients with secondary progressive MS but to a lesser extent than in primary progressive MS. As gangliosides are particularly enriched in the axonal membrane, these findings suggested that antiganglioside immune responses might contribute to the axonal damage in progressive forms of MS. The present study was performed to determine whether peripheral blood T cell responses to GM3 are also increased in progressive MS. Blood was collected from 98 untreated patients with MS (40 with relapsing-remitting, 27 with secondary progressive and 31 with primary progressive MS), 50 healthy subjects and 24 patients with other disorders of the CNS, and reactivity to GM1, GM3, GD1a, GD1b, GD3, GT1b, GQ1b and sulphatide was assessed by 6-day T cell proliferation assays. Increased T cell reactivity to GM3 and GQ1b occurred significantly more often in patients with primary progressive MS than in healthy subjects and patients with other CNS diseases. These findings suggest that ganglioside-specific T cells may contribute to the axonal damage in primary progressive MS.

Increased circulating antiganglioside antibodies in primary and secondary progressive multiple sclerosis

Plasma samples from 70 patients with multiple sclerosis (MS), 41 patients with other neurological diseases (OND), and 38 healthy subjects were examined for antibodies against gangliosides GM1, GM3, GD1a, GD1b, and GD3 using enzyme-linked immunosorbent assays. The percentages of subjects with increased anti-GM3 responses were significantly higher in the primary progressive MS (56.3%) and secondary progressive MS (42.9%) groups than in the relapsing-remitting MS (2.9%), healthy subject (2.6%), and OND (14.6%) groups. Elevated antiganglioside antibodies may be secondary to axonal damage or may be a cause of axonal damage and accumulating disability in progressive MS. In either case, they may serve as a marker of axonal damage in MS.

Polyclonal IgM anti-GM1 ganglioside antibody in patients with motor neuron disease and variants

Recent studies reported the presence of anti-ganglioside antibodies in occasional patients with motor neuron disease. We found polyclonal serum IgM anti-GM1 antibodies by an anti-GM1 enzyme-linked immunosorbent assay (ELISA) in 9 (19%) of 48 patients with motor neuron disease. A comparable frequency of IgM anti-GM1 antibodies was found in 4 (10%) of 40 sera from patients with other neurological disease. Three (17%) of 18 sera from the patients with motor neuron disease and 2 (17%) of 12 sera from patients with other neurological diseases had anti-GM1 immunostaining as shown by thin layer chromatography immunoblot. One patient with a lower motor neuron variant of motor neuron disease or motor axonopathy without multifocal conduction block had a markedly elevated polyclonal IgM anti-GM1 ELISA titer (greater than 1:64,000) with prominent immunostaining of GM1, moderate immunostaining of GM2, and weak and inconsistent immunostaining of GD1b by thin layer chromatography immunoblot. Treatment with prednisone resulted in clinical improvement despite increasing anti-GM1 antibody titers. These data indicate that patients with motor neuron disease have measurable levels of anti-ganglioside antibodies as frequently as patients with other neurological diseases. This contrasts with a small subgroup of patients with a lower motor neuron variant of motor neuron disease or motor axonopathy who have markedly elevated levels of serum anti-ganglioside antibodies and a clinical syndrome that is treatable with immunosuppression.

Monoclonal IgMs with anti-Gal(beta 1-3) GalNAc activity in lower motor neuron disease; identification of glycoprotein antigens in neural tissue and cross-reactivity with serum immunoglobulins

IgM monoclonal antibodies (M-proteins) with anti-Gal(beta 1-3)GalNAc and anti-Gal(beta 1-3)GlcNAc activity that bind to gangliosides GD1b and GM1, from two patients with lower motor neuron disease were tested for binding to neural glycoproteins. The M-proteins bound to several glycoproteins in the central and peripheral nervous system including to some in the non-myelin or axonal fraction only. Peanut agglutinin (PNA) which is specific for Gal(beta 1-3)GalNAc, bound to the same protein bands. Since serological studies revealed that the M-proteins were complexed to IgG, serum immunoglobulins were tested for presence of Gal(beta 1-3)GalNAc epitopes. Both PNA and the M-proteins bound to immunoglobulin heavy and light chains, suggesting that the circulating M-proteins bind to Gal(beta 1-3)GalNAc on other immunoglobulins. These studies indicate that in addition to gangliosides the M-proteins might bind to Gal(beta 1-3)GalNAc bearing glycoproteins in vivo and that carbohydrate epitopes on immunoglobulins might have a role in the development and regulation of autoantibodies which cross-react with neural antigens and may cause neurological disease.

Anti-glycolipid antibodies and their immune complexes in multiple sclerosis

Antibody titers against myelin constituents in sera and CSF of patients with multiple sclerosis (MS) were examined by a solid-phase radioimmunoassay. Anti-GM4 and anti-galactocerebroside antibody titers were significantly elevated in the CSF of MS patients, but not anti-GM1 and anti-myelin basic protein antibodies. In sera of MS patients, the titers of antibodies against these myelin constituents were not elevated. Total IgG level was also significantly elevated in the CSF, but not in the sera of MS patients. Immune complexes from the CSF of MS patients were dissociated by acid-ultrafiltration and assayed for antibodies to GM4, GM1, and galactocerebroside. Anti-GM4 and antigalactocerebroside antibody titers were significantly enhanced after acid dissociation and ultrafiltration. These data suggest that antibodies of the IgG class against GM4 and galactocerebroside are present in CSF of MS patients, and a significant number of them exist as immune complexes with their corresponding glycolipid antigens.

Effect of antiglycolipid antisera on the lipid composition of cultured mouse spinal cords

To examine the effect of antiglycolipid antibodies on demyelination, myelinated cultures of embryonic mouse spinal cords were treated by antigalactocerebroside (anti-GC), anti-GM1; and anti-GM4 antisera, and the lipid composition of the cultures were studied. The anti-GC antiserum-treated cultures, which exhibited severe morphologic signs of demyelination, revealed a significant reduction of cerebroside. The anti-GM4 or anti-GM1 antiserum-treated cultures, which exhibited mild degrees of demyelination, also had low contents of cerebroside. These results support our previous data showing that antiglycolipid antibodies cause demyelination in cultured mouse spinal cords, and suggest a possible role of myelin-specific glycolipids in the demyelination process.

Complement-dependent immune damage to liposomes containing gangliosides

Rabbit antiserum against mixed beef brain gangliosides served as an excellent source of antibodies to gangliosides GM1, GM3, GD1a, GD1b, and GT1b. Immune potency of antiserum was determined by complement-dependent damage to liposomes containing gangliosides as antigens. Antibody levels in antiserum to mixed gangliosides, when tested against individual gangliosides, were equivalent or superior to the levels obtained by immunization of rabbits with purified individual gangliosides. Naturally occurring antibodies to GM1, GD1b, and GM3 were observed in preimmunization sera. The levels of these natural antibodies, although easily high enough to serve as antiserum sources for liposome assay, were increased substantially following immunization. High titers of antibodies to GM1 and GD1b were observed in certain individual guinea pig sera, and selection of individual non-reacting guinea pig sera was necessary in order to obtain suitable complement sources when testing rabbit antibodies to liposomal GM1 and GD1b. The maximum plateau level of trapped glucose release from liposomes in the presence of saturating levels of antigen, antiserum, and complement was influenced strongly both by the method of removing untrapped glucose during liposome preparation and by the type of ganglioside incorporated into the lipid bilayer.

Abnormalities of serum and plasma components in patients with multiple sclerosis

Qualitative and quantitative abnormalities in protein and non-protein components of serum and plasma in patients with multiple sclerosis have been the subjects of numerous reports. In this review many of the more recent observations are documented and evaluated. It is concluded that at present the welter of information that has been gathered does not contribute in any major, coherent way to our understanding of the etiology or pathogenesis of the disorder. Several of the abnormalities that have been observed may be future candidates for biochemical markers for multiple sclerosis; at present none is sufficiently reliable, distinctive or easily performed to warrant the status of a useful diagnostic or prognostic test.

Antibodies to glycosphingolipids in patients with multiple sclerosis

Antibodies to one or more glycosphingolipids were detected by means of a liposome lysis assay in the sera of 60/81 patients with multiple sclerosis, 24/42 patients with systemic lupus erythematosus and in the majority of patients with cranial trauma or cerebrovascular accidents. Antibodies against ganglioside GM1 and asialo GM1 were found most commonly and they were frequently present in the same sera. Among patients whose sera contained antibodies to glycolipids, anti-GM1 alone occurred more frequently in patients with multiple sclerosis (14/59) than in systemic lupus erythematosus (1/22; p = 0.045) and antiasialo GM1 alone was more common in patients with lupus (9/22) than in patients with multiple sclerosis (8/59, p = 0.007). In 10 sera analyzed, all of the antibodies against these two glycolipids were of the IgM class, and some fluctuation in antibody titers was noted over a three-month period. The role of these antibodies in the initiation or perpetuation of inflammatory diseases of the central nervous system remains to be determined.

Immune lysis of lipid vesicles containing myelin basic protein or glycolipid antigens by multiple sclerosis and normal sera

We have compared the reactivity of sera from 34 multiple sclerosis (MS) patients and 32 normal (N) individuals with lipid vesicles containing myelin basic protein (BP) and several glycolipids reconstituted into a membrane environment. The ability of the sera to cause complement-mediated lysis of lipid vesicles containing these antigens was determined by measuring the release of a water-soluble spin label, tempocholine chloride, from the height of its electron spin resonance spectrum. Only 4 MS sera caused lysis of BP-containing vesicles which was comparable to that produced by specific antibody to BP. A number of both MS and N sera caused significant lysis of vesicles containing GM1 ganglioside or digalactosyldiglyceride. A few MS and N sera also caused significant lysis of vesicles containing GM2, GT1 and GD1a gangliosides. However, in no case was there a statistically significant difference between the mean lysis produced by MS and N sera. There was some overlap between the specific MS and N sera reactive to vesicles containing BP, GM1, GM2, and DGDG while a completely different group of MS and N sera were reactive to GT1 and GD1a gangliosides. This suggested that there was either antigenic cross reactivity between the two groups of glycolipids or two different origins of the immune response to the two groups of antigens. It was concluded that antibody-dependent complement fixation by these particular antigens, in the kind of lipid environment used, is not characteristic of or specific to MS.

A review of the immunogenic and immuno-modulatory properties of glycosphingolipids

This review summarizes recent data concerning the immunogenicity and immunomodulatory properties of glycosphingolipids. Many murine monoclonal antibodies that react with glycosphingolipids have been described recently. Most of these antibodies have been elicited by immunization with tumor cells and they may also bind to glycoproteins that contain similar carbohydrate sequences. Immunization with a variety of tissues, murine teratocarcinomas, myeloid leukemia, and carcinomas of the human lung, colon and stomach, has elicited antibodies that react with the sugar sequence Gal beta 1-4[Fuc alpha 1-3]GlcNAc beta 1-3Gal----. The suppression of lymphocyte responses to mitogens and antigens by gangliosides in vitro has led to suggestions that these glycolipids possess immunodulatory properties in vivo. The in vitro studies were performed by incubating mononuclear cells with either dispersions of pure gangliosides or ganglioside-containing liposomes. In vivo gangliosides are found only in cell membranes or in lipoproteins, where they represent a small mole percent of total lipids, and there is little information about the transfer of gangliosides from lipoproteins to cells in vivo. A role for gangliosides as modulators of the immune response is an interesting possibility that is not supported by physiologically relevant data at present.

Immunological expression of gangliosides in multiple sclerosis and in a demyelinating model disease in rabbits

Accumulating evidence suggests that the process of demyelination in MS might involve an autoimmune response to one or more myelin components. A combination of myelin basic protein and myelin haptens was considered as possibly enhancing a cellular or humoral autoimmune reaction in MS. In line with this motion we have used an in-vitro E-rosette assay that correlates with in-vivo delayed hypersensitivity to demonstrate specific immunologic sensitivity of lymphocytes from MS patients to polysialogangliosides. A recent report that only lymphocytes from patients in relapse, but not in remission, are primed by gangliosides, underscores the relevance of the antigenic expression of gangliosides during the active pathological phase of the disease. The antigenic capacity of gangliosides to induce upon immunization a neurological disorder featured by demyelination in the CNS was demonstrated in rabbits. This and previous reports on the induction of peripheral demyelination in rabbits immunized with gangliosides will be further analyzed to gain insight on the possible role of these myelin lipid components as targets for an autoimmune mechanism in MS.

Immune reactivity against membranes containing ganglioside GM1 in chronic-progressive multiple sclerosis: observation by spin-membrane immunoassay

A spin-membrane immunoassay has been employed to examine the immune reactivity of whole serum from patients with chronic-progressive multiple sclerosis (CPMS) against liposomes containing ganglioside GM1. Exposure to serum resulted in complement-mediated lysis of the GM1-liposomes. No lysis occurred with liposomes devoid of ganglioside. The mean (+/- S.E.M.) lysis values were 52.6 (+/- 9.8)% for fifteen CPMS patients and 32.9 (+/- 7.2)% for nine controls. The difference between the means was highly significant (student's t-test, P less than 0.0001), indicating increased anti-ganglioside immunity in patients with CPMS.

Preparation of anti-GM4 antiserum and its assay by a solid-phase radioimmunoassay

Anti-GM4 antiserum was prepared from rabbits by immunization with pure human brain GM4 ganglioside in complete Freund's adjuvant and methylated bovine serum albumin. None of the immunized animals developed any clinically apparent neurological dysfunction. The antiserum titer and specificity were analyzed by double immunodiffusion and a novel solid-phase radioimmunoassay (RIA). In the latter procedure, microtiter plate wells were coated first with the glycolipid antigen, followed by sequential application of antiserum and [125I]-Staphylococcal Protein A. The absorbed radioactivity in the well was then counted. Employing the RIA procedure, anti-GM4 antibody achieved a titer of 1:1600. The antiserum also exhibited a high degree of specificity to GM4; cross-reactivity with glycolipids of similar structure was negligible. The production of highly specific antiserum to GM4 and the feasibility of detecting antibodies to glycolipid antigens by a convenient solid-phase RIA should be useful to further study the biological and immunological roles of GM4 and other glycolipids in the central nervous system.

Elevated ganglioside concentration in serum and peripheral blood lymphocytes from multiple sclerosis patients in remission

The ganglioside concentration in pooled serum from 20 patients with clinically definite multiple sclerosis (MS) was determined and compared with that in pooled serum from a similar number of healthy blood donors. There as a significant increase in the concentration of ganglioside-bound sialic acid from 691 +/- 57 micrograms/100 ml in the control sera to 926 +/-m 83 micrograms 100 ml in MS patients' sera. The profile of individual gangliosides in the two groups was identical, the four main structures being GM3, GD3, and GD1a and GT1b. The ganglioside pattern and concentration in peripheral blood lymphocytes derived from MS patients and controls was identical with the predominant GM3, and small proportions of Gd3. MS lymphocytes also showed a 39% increase in ganglioside content over control lymphocytes. The implication of such pronounced ganglioside increases is discussed with regard to the impaired immunocompetence of lymphocytes reported in MS.

Multi-sialo brain gangliosides are powerful stimulators of active E-rosetting lymphocytes from multiple sclerosis patients

Peripheral blood T lymphocytes from all of 14 patients with clinically definite multiple sclerosis (MS) were significantly stimulated by MS brain gangliosides in the active rosetting of sheep erythrocytes. Fractionated mono- and disialogangliosides were devoid of any stimulating effect on MS lymphocytes whereas the trisialoganglioside GT1 and to a greater extent the tetrasialoganglioside GQ1b were fully effective at a dose as low as 2 x 10(-18) moles. Gangliosides extracted from MS brains or from MS brain myelin were far more effective than gangliosides derived from control human brains or from bovine and mouse brains, suggesting the importance of highly sialylated gangliosides occurring to a greater extent in MS brain as previously reported. Lymphocytes from only 3 out of 24 other neurological patients were stimulated by the slow migrating gangliosides in the same way, but none of 32 healthy subjects responded to these gangliosides in the active E-rosette test. Lymphocytes from 5 to 8 patients with unilateral optic neuritis reacted positively to brain gangliosides by rosette formation, several weeks before a similar reaction to myelin basic protein was evident. Our data are compatible with a release of gangliosides during demyelination or other CNS degenerative processes occurring in multiple sclerosis.

Myelin basic protein interacts with the myelin-specific ganglioside GM4

Demyelinated plaques in multiple sclerosis have decreased amounts of both myelin basic protein and sialosylgalactosylceramide (GM4), a ganglioside specifically localized in myelin and oligodendroglia of the central nervous system. We have found that myelin basic protein is capable of releasing large quantities of entrapped [14C]glucose from multilamellar liposomes containing GM4. If the conformation of GM4 in liposomal membranes resembles that of GM4 in its natural environment, basic protein and GM4 may be associated within the myelin sheath of the central nervous system and their interaction altered in demyelinating diseases such as multiple sclerosis.