Immunoglobulin elution from multiple sclerosis brain

Oligoclonal IgG antibodies in multiple sclerosis target patient-specific peptides

IgG oligoclonal bands (OCBs) are present in the cerebrospinal fluid (CSF) of more than 95% of patients with multiple sclerosis (MS), and are considered to be the immunological hallmark of disease. However, the target specificities of the IgG in MS OCBs have remained undiscovered. Nevertheless, evidence that OCBs are associated with increased levels of disease activity and disability support their probable pathological role in MS. We investigated the antigen specificity of individual MS CSF IgG from 20 OCB-positive patients and identified 40 unique peptides by panning phage-displayed random peptide libraries. Utilizing our unique techniques of phage-mediated real-time Immuno-PCR and phage-probed isoelectric focusing immunoblots, we demonstrated that these peptides were targeted by intrathecal oligoclonal IgG antibodies of IgG1 and IgG3 subclasses. In addition, we showed that these peptides represent epitopes sharing sequence homologies with proteins of viral origin, and proteins involved in cell stress, apoptosis, and inflammatory processes. Although homologous peptides were found within individual patients, no shared peptide sequences were found among any of the 42 MS and 13 inflammatory CSF control specimens. The distinct sets of oligoclonal IgG-reactive peptides identified by individual MS CSF suggest that the elevated intrathecal antibodies may target patient-specific antigens.

Extraction and purification of active IgG from SSPE and MS brain

Immunoglobulin (Ig) G was purified from soluble and membrane fractions of postmortem subacute sclerosing panencephalitis (SSPE) brain, multiple sclerosis (MS) brain plaque-periplaque white matter, and normal human brain (NHB) white matter. After homogenization in 0.32 M sucrose and removal of cell debris and nuclei by low-speed centrifugation, soluble and crude membrane fractions were separated by ultracentrifugation. After removal of sucrose by dialysis, IgG was isolated from the soluble fraction by protein A affinity chromatography. IgG was obtained from the membrane fraction by elution at low pH and purification from the eluate by protein A chromatography. Whereas very little IgG was in NHB white matter, significant levels of IgG were recovered from both SSPE and MS brain. Both immunocytochemical staining of measles virus-infected cells in tissue culture and protein immunoblotting of virus-infected cell lysates showed that the IgG from SSPE brain contained activity specific for measles virus protein. The abundance, purity and functional activity of IgG extracted from SSPE and MS brain indicate that IgG extracted from the brain of humans with an inflammatory disease of unknown etiology can be used to identify its corresponding antigen.

Autoantibodies to myelin basic protein within multiple sclerosis central nervous system tissue

Previous research has demonstrated that free (F) and bound (B) anti-myelin basic protein (anti-MBP) can be detected in the cerebrospinal fluid (CSF) of patients with active multiple sclerosis (MS). The purpose of this report was to determine whether the immunoglobulin G (IgG) isolated from central nervous system (CNS) tissue of MS patients contains anti-MBP. IgG was detected in free and bound hydrosoluble protein extracts obtained from the brain, spinal cord and optic nerves of a patient with clinically definite and neuropathologically confirmed MS. IgG was purified from free protein extracts from brain and spinal cord by Protein G-Sepharose affinity chromatography. Anti-MBP was detected by a solid phase radioimmunoassay (RIA) in all free and bound protein extracts. Anti-MBP was isolated from purified IgG from brain and spinal cord by MBP-Sepharose affinity chromatography. Free anti-MBP in the context of whole protein extracts, within purified IgG or as purified antibody as well as tissue-bound anti-MBP in the context of whole protein extracts was completely neutralized by human MBP (h-MBP) and synthetic peptide No. 56 (residues 75-95 of h-MBP) and did not react with synthetic peptide No. 41 (residues 35-58 of h-MBP). Anti-MBP which has previously been detected in the CSF of MS patients with active disease is also present as free antibody in the extracellular space of MS-central nervous system tissue and in a smaller proportion as tissue-bound antibody.

Increased synthetic peptide specificity of tissue-CSF bound anti-MBP in multiple sclerosis

Free and bound hydrosoluble protein extracts were prepared from four anatomical areas of a multiple sclerosis (MS) cerebrum and from corresponding anatomical areas of a normal (non-MS) control. Increased levels of IgG and anti-myelin basic protein antibodies (anti-MBP) were detected in all MS samples and they were undetectable in the controls. IgG and anti-MBP from free (unbound) hydrosoluble protein extracts are defined as free IgG and free anti-MBP while IgG and anti-MBP from tissue bound protein extracts are defined as bound IgG and bound anti-MBP. IgG was purified from free protein extracts by protein G Sepharose affinity chromatography and anti-MBP was further isolated from purified IgG by antigen specific (MBP) Sepharose affinity chromatography. Free and bound anti-MBP were reacted with 20 synthetic peptides of human MBP prepared by the Fmoc method. Free anti-MBP, whether in the context of whole protein extracts, or as purified IgG or as purified antibody was completely neutralized by peptides #12, #15, #56 and #56* containing overall residues 75-106, partially neutralized by peptides #27, #16 and #21 containing overall residues 61-83 and did not react with the remaining 13 peptides. Tissue bound anti-MBP was completely neutralized only by peptides #12, #15, #56 and #56* (overall residues 75-106) and showed no reactivity towards the remaining 16 peptides including peptides #27, #16 and #21. Synthetic peptide specificity of free anti-MBP purified from MS cerebrum was identical to previously reported specificity of free anti-MBP from MS cerebrospinal fluid (CSF), while tissue bound anti-MBP, as well as bound anti-MBP from CSF had a more restricted synthetic peptide specificity than free anti-MBP. This suggests that the most likely epitope of anti-MBP is located between residues 84 and 95 of human MBP just proximal to the tri-proline sequence (99-101).

Immunoglobulin G in multiple sclerosis brain

We extracted free and bound IgG from plaques and normal-appearing white matter of multiple sclerosis (MS) brains. By isoelectric focusing (IEF), three patterns of IgG distribution were seen: (A) a restricted high-pI distribution with a specific band at low pH, (B) a restricted high-pI pattern, and (C) a broad pI pattern similar to that of the unbound IgG extracted at neutral pH. In one MS brain, we compared the IEF pattern of plaque material with that of normal-appearing white matter (NAWM); the low-pH extract of plaque material (PM) had a restricted pattern at high pI. In another MS brain, a specific band of bound IgG was found. These data suggest that MS lesions expose an antigen(s) unique to MS. B cells consequently might be stimulated by a disease-related antigen(s) in the MS lesion.

Intrathecal synthesis of autoantibodies to myelin basic protein in multiple sclerosis

A solid phase radioimmunoassay was used to detect anti-myelin basic protein (MBP) antibodies in the CSF and serum of multiple sclerosis (MS) patients and controls. CSF and serum samples were assayed prior to acid hydrolysis in order to detect free anti-MBP as well as after acid hydrolysis to measure the total (free and bound) amount of antibody. An anti-MBP index controlling for serum levels as well as the degree of breakdown of the blood brain barrier was used to estimate intrathecal synthesis of anti-MBP. MS patients with acute exacerbations or chronically progressive disease have significantly elevated levels of both free and total CSF anti-MBP. The anti-MBP index is also significantly increased in MS patients with both forms of active disease. Anti-MBP antibodies are intrathecally produced in MS patients with active disease.

Effect of methylprednisolone on CSF IgG parameters, myelin basic protein and anti-myelin basic protein in multiple sclerosis exacerbations

Clinical exacerbations of multiple sclerosis (MS) are characterized by elevated levels of cerebrospinal fluid (CSF) myelin basic protein (MBP). The purposes of this study were to determine whether anti-MBP antibodies are present in increased titer in CSF of MS patients with exacerbations, and whether they can be suppressed by the administration of immunosuppressive dosages of methylprednisolone (MP). A solid phase radio-immunoassay (RIA) was used to detect free and total anti-MBP antibodies before and after acid hydrolysis of CSF. In MS exacerbations, the majority of elevated anti-MBP is in the free form. With the exception of subacute sclerosing panencephalitis (SSPE) and some cases of post infectious encephalomyelitis, anti-MBP antibodies are not present in either MS patients in remission or in non-MS controls. Anti-MBP levels remained elevated over a 10 day period when patients are managed by bed rest only or when treated with intravenous (IV) ACTH. IV administration of MP in "high" (160 mg/day) or "mega" (2 g/day) dosages produces a highly significant reduction of both MBP (p less than 0.01) and anti-MBP (p less than 0.001) levels. Total intrathecal IgG synthesis is also significantly suppressed by IV-MP but not by ACTH.

Oligoclonal IgG in multiple sclerosis and subacute sclerosing panencephalitis brains

IgG was obtained from multiple sclerosis (MS) and subacute sclerosing panencephalitis (SSPE) brain materials by elution at neutral and acid pH, and by freezing and thawing. Serum, cerebrospinal fluid (CSF), and brain eluates were compared by isoelectric focussing (IEF) with sensitive peroxidase-anti-IgG staining. In 3 MS cases, different plaques or regions of the same brain had IgG patterns with some common and some different bands. Pooled white matter eluates contained the summation of bands seen in individual plaques or regions. Comparison of serum, CSF, and neutral and acid brain eluate IgG patterns showed many common bands but also unique bands. In two SSPE cases, eluates from different regions of the same brain showed virtually identical IgG patterns. Comparisons of serum, CSF, and neutral and acid eluates of the same brain also showed a common pattern of bands. Similarities in IgG patterns of sera, CSF, and regional brain eluates, from single cases of SSPE, suggest a common response to the same antigen in all regions or compartments. Differences in IgG patterns of sera, CSF, pooled brain eluates, and plaques or regional eluates from single cases of MS, suggest: either that (a) all MS oligoclonal IgG is "nonsense' antibody in terms of disease pathogenesis, or (b) much of the MS oligoclonal IgG is "nonsense' antibody, present as part of a specific oligoclonal immune reaction.

Immunoglobulins in demyelinating lesions in canine distemper encephalitis. An immunohistological study

The brains of 14 dogs with canine distemper encephalitis were examined with immunohistologic techniques to search for immunoglobulin in demyelinating lesions. Four types of lesions presumably representing a temporal sequence of lesion development were distinguished. Immunohistologic findings included immunoglobulin bearing lymphoid cells, amorphous Ig containing material, immunoglobulin bound to the tissue and immunoglobulin containing macrophages and astrocytes. The humoral immune response was absent or very minimal in acute lesions and very intense in chronic lesions. It was concluded that early demyelination in canine distemper encephalitis occurs in the absence of a local humoral immune response but that this response may aggravate and accelerate myelin destruction in the later stages of the disease.

Isoelectric focusing of IgG eluted from multiple sclerosis and subacute sclerosing panencephalitis brains

Elevated IgG distributed in oligoclonal bands is characteristically observed in the cerebrospinal fluid (CSF) of patients with multiple sclerosis (MS) or subacute sclerosing panencephalitis (SSPE). Similarly, IgG in bands has been detected in neutral saline (NS) and acid eluates of brain material from these two diseases. We have now used isoelectric focusing (IEF) to compare IgG eluted from control brain, three plaques and a white matter pool of an MS brain, and three regions of an SSPE brain. A direct peroxidase-conjugated anti-human IgG staining technique was used to stain IgG exclusively and to visualize the minute amounts of IgG obtained from individual MS plaques. Eluates from individual MS plaques have distinct IgG patterns; in contrast, those from separate SSPE brain areas have essentially identical IgG patterns. The identical IgG patterns in three areas of SSPE brain suggest a common response to the same antigen. The different IgG patterns among MS plaques suggest: (1) variable response to the same 'MS antigen' in each plaque, (2) response to different MS antigens in different plaques, (3) synthesis of 'nonsense' antibodies irrelevant to the pathogenesis of MS in each plaque, or (4) some combination of the above.

A new solid-phase radioimmunoassay to measure IgG secreted by cultured human lymphocytes

We describe a simple solid-phase radioimmunoassay (RIA) to detect IgG based on competitive binding between radiolabeled and unlabeled IgG for anti-IgG antibody physically adsorbed to the wells of polyvinyl microtiter plates. The assay is sensitive (1 ng), rapid, and is particularly suited for studies of in vitro IgG secretion by human peripheral blood lymphocytes, since such studies require large numbers of cultures. Conditions which permit measurement, by means of this assay, of helper and suppressor T cell effects on IgG production by human B cells in culture are described.