Antibody-dependent lymphocyte cytotoxicity against basic protein of myelin in multiple sclerosis

Evidence for the role of B cells and immunoglobulins in the pathogenesis of multiple sclerosis

The pathogenesis of multiple sclerosis (MS) remains elusive. Recent reports advocate greater involvement of B cells and immunoglobulins in the initiation and propagation of MS lesions at different stages of their ontogeny. The key role of B cells and immunoglobulins in pathogenesis was initially identified by studies in which patients whose fulminant attacks of demyelination did not respond to steroids experienced remarkable functional improvement following plasma exchange. The positive response to Rituximab in Phase II clinical trials of relapsing-remitting MS confirms the role of B cells. The critical question is how B cells contribute to MS. In this paper, we discuss both the deleterious and the beneficial roles of B cells and immunoglobulins in MS lesions. We provide alternative hypotheses to explain both damaging and protective antibody responses.

Antibodies against the myelin oligodendrocyte glycoprotein and the myelin basic protein in multiple sclerosis and other neurological diseases: a comparative study

In experimental animal models of multiple sclerosis demyelinating antibody responses are directed against the myelin oligodendrocyte glycoprotein (MOG). We have investigated whether a similar antibody response is also present in multiple sclerosis patients. Using the recombinant human extracellular immunoglobulin domain of MOG (MOG-Ig) we have screened the sera and CSFs of 130 multiple sclerosis patients, 32 patients with other inflammatory neurological diseases (OIND), 30 patients with other non-inflammatory neurological diseases (ONND) and 10 patients with rheumatoid arthritis. We report that 38% of multiple sclerosis patients are seropositive for IgG antibodies to MOG-Ig compared with 28% seropositive for anti-myelin basic protein (MBP). In contrast, OIND are characterized by similar frequencies of serum IgG antibody responses to MOG-Ig (53%) and MBP (47%), whereas serum IgG responses to MOG-Ig are rare in ONND (3%) and rheumatoid arthritis (10%). Anti-MBP IgG antibodies, however, are a frequent finding in ONND (23%) and rheumatoid arthritis (60%). Our results provide clear evidence that anti-MOG-Ig antibodies are common in CNS inflammation. However, in OIND these antibody responses are transient, whereas they persist in multiple sclerosis. We demonstrate that the serum anti-MOG-Ig response is already established in early multiple sclerosis (multiple sclerosis-R0; 36%). In later multiple sclerosis stages frequencies and titres are comparable with early multiple sclerosis. In contrast, the frequency of anti-MBP antibodies is low in multiple sclerosis-R0 (12%) and increases during disease progression in relapsing-remitting (32%) and chronic progressive multiple sclerosis (40%), thus suggesting that anti-MBP responses accumulate over time. Finally we provide evidence for intrathecal synthesis of IgG antibodies to MOG-Ig in multiple sclerosis.

Cytolysis of oligodendrocytes is mediated by killer (K) cells but not by natural killer (NK) cells

The cytotoxic activity of killer (K) cells against enriched cultures of bovine oligodendrocytes (BOL) was investigated in multiple sclerosis (MS) and controls. Human K cells mediated cytotoxicity to primary cultures of BOL in the presence of anti-BOL antiserum in all study groups, while BOL were resistant to human natural killer (NK) cells. Cytotoxic activity was significantly reduced in MS when compared to age-matched normal controls but not when compared to other neurologic disease (OND) patients. K cell-mediated lysis of BOL could also be induced with anti-galactocerebroside antibody but not with other antibodies including those specific for OL antigens (myelin basic protein, proteolipid apoprotein, and 2',3'-cyclic nucleotide 3'-phosphodiesterase). Enrichment of the effector population indicated that antibody-dependent cell-mediated cytotoxicity (ADCC) to BOL was mediated by large granular lymphocytes, and the effector population was further characterized by flow cytometry. The effector cells mediating ADCC could be inhibited by protein A of Staphylococcus aureus, and by K562 cells in cold competition assay. These observations indicate that oligodendrocytes are resistant to NK cells but are susceptible to cytolysis mediated by K cells. This may represent a potentially important immune mechanism in the pathogenesis of MS.

Are anti-brain antibodies in multiple sclerosis directed to myelin basic protein? Studies employing the Shiverer mouse mutant

The dysmyelinating mouse mutant Shiverer has a severe and relatively selective deficiency of myelin basic protein (MBP) in the central and peripheral nervous system. Nevertheless, Shiverer brain and control-mouse brain showed similar antigenic titers when tested by a complement fixation assay against a panel of 14 multiple sclerosis (MS) sera and 6 MS CSF samples known to represent several specificities of antibrain antibodies. By analogy with experimental allergic encephalomyelitis, a sensitization to MBP has been proposed in MS. Our results, however, show that antibodies to other CNS antigens are quantitatively more important in this disease.

Reactivity of sera and isolated monoclonal IgM from patients with Waldenström's macroglobulinaemia with peripheral nerve myelin

Sera of 23 patients with Waldenström's macroglobulinaemia and six monoclonal IgM paraproteins, which had been isolated from these sera, were examined for reactivity against peripheral nerve tissue. Of these 23 patients, 12 had clinical signs of peripheral polyneuropathy (PN). Using an indirect immunofluorescence method, all sera and monoclonal IgM preparations reacted with peripheral nerve structures, displaying a distinct granular fluorescence pattern with anti-IgM sera. The Waldenström sera reacted mainly with structures at the border of the myelin sheath, as well as between myelin and axon, and occasionally with the axon itself. There was no difference between sera of patients with PN and those without. Negative results were obtained in a complement fixation assay. Of the 23 sera, 15 reacted in an antibody-dependent lymphocyte-mediated cytotoxicity reaction (ADLC) with peripheral nerve myelin, and to a much lesser extent with myelin basic protein from CNS. Five of the six isolated monoclonal IgM preparations also gave positive ADLC reactions. These results constitute additional evidence for an immunological mechanism in the pathogenesis of PN in Waldenström's macroglobulinaemia.

Immune responses to myelin antigens in multiple sclerosis

Multiple sclerosis is considered to be a putative immunopathologic disease and there has been considerable effort over the years to prove an autoimmune etiology for it. To date, the evidence is all indirect and there is no proof of either antibody and/or cell-mediated hypersensitivity to any single identifiable CNS constituent whether a constituent of normal CNS or specific to the CNS of MS patients.

Cytotoxic activity of peripheral blood and cerebrospinal fluid lymphocytes from patients with multiple sclerosis and other neurological diseases: analysis at the single cell level of the relationship of cytotoxic effectors and interferon-producing cells

The production of interferon (IFN alpha) in relationship to NK and ADCC activity of peripheral blood and cerebrospinal lymphocytes was examined at the single cell level in patients with multiple sclerosis (MS) and other neurological diseases (OND) compared with age- and sex-matched controls. IFN-producing cells were assessed by indirect immunofluorescent scoring of cytoplasmic IFN+ cells. Peak production of cytoplasmic IFN alpha in nylon wool-passed ( NWP ) cells occurred between 5 and 17 hr in vitro under the inductive stimulus of MOLT 4, K562, or antibody-coated Chang liver cells. The proportion of K562- and MOLT 4-induced IFN alpha-positive cells in the total lymphocyte and target-binding cell (TBC) population was significantly lower in MS NWP -peripheral blood lymphocytes (PBL) than in OND and normal controls; this was in direct relationship to a decreased percentage of NK cells in MS PBL. In contrast MS cells responded the same as controls (total IFN+ cells) or higher than controls (IFN+-TBC) after IFN alpha induction by antibody-coated Chang, the ADCC target, in parallel with elevated ADCC activity by MS PBL. MS CSF contained a higher proportion of total IFN+ cells but a similar proportion of IFN+-TBC as their homologous NWP PBL population. In OND CSF, both the percentage of total IFN+ and the percentage of IFN+-TBC were higher than in OND blood and higher than their respective MS CSF populations. The relationship of IFN-producing cells in the central nervous system (CNS) to putative cytotoxic cells is discussed.

Plasma exchange in neurological diseases. A critical approach

The rationale for and results of plasma exchange (PE) in the therapy of different immune-mediated neurological diseases such as myasthenia gravis, multiple sclerosis, acute and chronic-relapsing Guillain-Barré syndromes, polymyositis, dermatomyositis and amyotrophic lateral sclerosis are reviewed. Dialysis dementia and Refsum's disease, subacute sclerosing panencephalitis and schizophrenia are mentioned, too. If we exclude the treatment of acute Guillain-Barré syndrome, where PE alone appears to be sufficient to produce recovery or improvement, the combined use of immunosuppressive drugs and/or lymphocytapheresis is probably needed in the treatment of the other diseases. PE allows the disease to be controlled rapidly while long-term pharmacological control is established. An underlying theme in this review is the need of adequately controlled studies or at least of large case lists with exhaustive reports concerning both positive and negative results since a new perspective is needed for this topic. Nonetheless, a number of uncontrolled observations suggest that probably PE effectiveness in most immune-mediated neurological diseases could be proven if the requisite trials were performed.

Cell-mediated cytotoxicity by peripheral blood lymphocytes against basic protein of myelin, encephalitogenic peptide, cerebrosides and gangliosides in multiple sclerosis

In studies on 50 patients with multiple sclerosis (MS), all cases in an active stage of the disease, regardless of whether the course was relapsing or chronic progressive, and not dependent on the severity of the disease, it was possible to demonstrate a high cytotoxicity of the T-lymphocytes against the basic protein of myelin (MBP), encephalitogenic peptide, cerebrosides and gangliosides. During an inactive stage of the disease the cytotoxicity was much less and values could be reached which also occur in patients with other organic neurological diseases (OND). Similarly, in the individual case a close correlation of the degree of cytotoxicity to the course of MS was recognizable. It seemed that a cytotoxicity above 20% against the encephalitogenic peptide is specific for MS, since it could not be confirmed in 20 healthy persons and 50 patients with OND. A specificity of cytotoxicity against cerebrosides and gangliosides as well as for MBP does not exist in MS. Only the cytotoxicity against the encephalitogenic peptide can be considered as the pathogenic factor for the demyelinization process in MS. Immunosuppressive therapy with corticosteroids and azathioprine had no significant influence on the cytotoxicity.

A longitudinal study of antibrain antibodies in multiple sclerosis

The presence of complement-fixing antibrain antibodies is a distinctive feature of multiple sclerosis (MS). In a longitudinal study of 35 MS patients antibrain antibody titres in serum were followed for up to 5 years; in 18 of them also CSF titres were determined. No consistent correlations between antibrain antibody titres and clinical events were found. Thus, MS relapses are not caused by a general increase in antibrain antibody titres, and conversely the relapses did not cause a boosting of antibrain antibodies. Significant variations in the local plaque environment are, however, not ruled out by the present results.

Antibrain antibodies in multiple sclerosis. Relation to clinical variables

IgG antibrain antibodies (ABA) of several specificities can be demonstrated in multiple sclerosis (MS) with the complement fixation technique. This technique seems to discriminate between IgG specifically and non-specifically bound to CNS preparations. Complement-fixing ABA were titrated in paired serum and CSF samples from 87 patients with clinically definite MS, 15 patients with probable MS, 29 patients with other neurological diseases, and 13 "healthy" controls. In addition, sera from 55 non-MS patients were tested. In 40% of the sera and 88% of the CSF samples from patients with clinically definite MS, ABA reacting with human brain homogenate were demonstrated. The corresponding figures for probable MS were 21% and 73%, and for the controls 11% and 6%. Two of 9 sera from patients with the Guillain-Barré syndrome were strongly positive. There was a tendency for higher CSF ABA titres in younger MS patients and in those with an earlier onset of disease. ABA titres in serum and CSF were both correlated with a more malignant course. Irrespective of the mechanism of induction of ABA in MS--an excessive immunogenic stimulation and/or a defective immunoregulation--they are potentially pathogenic in several ways, e.g. (1) by direct antibody action. (2) by interaction with complement, (3) by antibody-dependent K-cell-mediated cytotoxicity, and (4) by interaction with phagocytic cells. Of several correlations among the routine CSF variables in MS, the finding of more pronounced abnormalities in male patients was notable.

Application of high performance liquid chromatography to the preparation of encephalitogenic myelin basic protein

Two preparations of myelin basic protein (MBP) were derived from an acid excretion of chloroform-methanol defatted bovine spinal cord. The first was purified by ion-exchange chromatography using guanidine-HCl; the second, by high performance liquid chromatography (HPLC) using a triethylamine eluant. Both methods of preparation yield MBP which is identical on acid-urea polyacrylamide gel electrophoresis and which has identical encephalitogenic potency. Because of the greater time-efficiency of the HPLC system with no deleterious side effects due to buffer contamination, this latter method can be recommended for MBP purification.

Specificity of antibody-dependent lymphocyte cytotoxicity against cerebral tissue constituents in multiple sclerosis. Studies with basic protein of myelin, encephalitogenic peptide, cerebrosides and gangliosides

In patients with multiple sclerosis (MS) there is not only an antibody-dependent lymphocyte cytotoxicity (ADLC) against basic protein of myelin (MBP), as was demonstrated earlier, but also against encephalitogenic peptide, cerebrosides and gangliosides. The reaction against cerebrosides and gangliosides is not specific for MS; it is also frequently positive in patients with other neurological diseases (OND), syphilis and rheumatoid arthritis. The ADLC against encephalitogenic peptide shows a very high specificity for MS. Out of 35 cases with OND, 23 had a positive result with MBP, but only one with encephalitogenic peptide. Patients with syphilis and rheumatoid arthritis reacted negatively without exception. According to this, the encephalitogenic peptide is a highly specific antigen for MS; MBP shows less specificity. The ADLC against the encephalitogenic peptide shows a markedly increased sensitivity in MS compared with MBP. Specificity and frequency of positive findings with encephalitogenic peptide support the pathogenic significance of the reaction in MS.

Experimental allergic encephalomyelitis induced by basic protein with synthetic adjuvant in comparison with Freund's complete adjuvant. Role of antibodies in correlation with the clinicopathological features

Experimental allergic encephalomyelitis (EAE) was induced in guinea pigs with bovine myelin basic protein (BP) with adjuvant of either synthetic muramyl dipeptide (Mdp) or Mycobacterium tuberculosis (Tbc). The following results were obtained: (1) The body temperature of the animals was studied serially after sensitization and its elevation was shown to be an early sign of EAE. (2) Several animals developed the clinical and histological signs of hyperacute EAE. (3) An optimal combined dosage of BP and adjuvant was found for induction of clinical EAE and for the the production of complement fixing (CF) antibodies. (4) Little passive hemagglutinating (PH) antibody was produced by single immunization. These results displayed no essential difference in EAE induced by either adjuvant. (5) Detectable PH antibodies developed later in addition to CF antibodies in a few animals immunized with Tbc adjuvant. These animals were skin-tested to BP, and had recovered from body weight loss or limb weakness. The results suggest that humoral antibodies play a role in modifying the disease process, even if they are not essential in production of EAE.

Studies of rat antibodies specific for myelin basic protein (MBP). Antibody-dependent cell-mediated lysis of MBP-sensitized targets in vitro

Rats immunized with rat myelin basic protein (MBP) in an encephalitogenic regimen produce antibodies which cooperate with spleen cells from unimmunized rats in the specific lysis of MBP-sensitized chicken erythrocytes (MBP-CRBC) in vitro. Antibodies against MBP capable of participating in antibody-dependent cell-mediated cytotoxicity (ADCC) were detected in serum 9 days post immunization, and prior to the onset of experimental allergic encephalomyelitis (EAE). Measurements based on a sensitive radioimmunoassay technique had previously established that anti-MBP activity emerges by day 9, early enough to participate in events leading up to EAE. The ADCC assay was designed to further characterize functions of immunoglobulins associated with the humoral response to MBP, with emphasis on the cytophilic properties of early antibodies. The assay described was found to be nearly as sensitive as the RIA and could detect specific syngeneic rat anti-MBP at concentrations of about 0.03 pmoles/ml serum. Whether ADCC-type reactions take place in the central nervous system during acute EAE is not known; however, the presence of early cytophilic antibody in serum suggests that humoral immunity may play an ancillary role to that demonstrated for T-cell immunity in EAE.