Production and characterization of monoclonal antibodies to peripheral and central nervous system myelin.

Monoclonal antibodies against P0, myelin basic protein, or myelin-associated glycoprotein were generated by fusing mouse myeloma cells with spleen cells from BALB/c mice immunized with central and peripheral nervous system myelin proteins. The antibodies secreted were either IgG, IgM, or IgA. Clone C6B5 (iso-type IgM) secreted antibody(ies) that bound to both myelin basic protein and myelin-associated glycoprotein, although binding of antibody to myelin basic protein as detected by the immunoblot technique appeared to be much less than to the myelin-associated glycoprotein. Antibodies were characterized in solid-phase radioimmunoassay for their species cross-reaction, and histologically for the specificity of binding to myelin in central and peripheral nervous system tissues. These monoclonal reagents should prove valuable in studying CSF and myelin-producing cells, since in both cases the concentration of myelin proteins is low.

Association of CSF IgG concentration and immunoglobulin allotype in multiple sclerosis and optic neuritis.

The cerebrospinal fluid (CSF) and serum from 64 patients with multiple sclerosis (MS) and 47 patients with monosymptomatic optic neuritis (ON) were analyzed for the distribution of allotypic determinants on IgG and compared to similar samples from 51 patients with other neurological diseases (OND) as well as to serum samples from 97 healthy controls. The results indicate a significantly increased frequency of the haplotypes Gm a;g and Gm a,x;g among MS patients (P = 0.024) with an associated increase in relative risk for MS among individuals with the Gm a,(x);g haplotypes compared to those individuals without them (P = 0.014). Among MS patients, those with the Gm a,(x);g haplotypes had significantly higher CSF levels of IgG than those without (P = 0.016); levels of serum IgG did not covary with Gm haplotype. Two-way analysis of variance indicates that familial cases have significantly higher levels of CSF IgG than nonfamilial cases (P less than 0.001) and that familial cases with the Gm a,(x);g haplotypes have the highest CSF IgG levels (P less than 0.005). There was no correlation between Gm haplotype and CSF or serum IgG levels in patients with ON or OND. The allotype effects were independent of age at onset and duration of disease. In all patients, regardless of disease classification, the phenotypes found in serum samples were identical to those found in CSF samples. The data presented support the hypothesis that the etiology of MS has as one of its parameters an immunoregulatory/immunogenetic factor. The successful analysis of these various parameters will provide useful information not only about MS but also about general principles of human immune responsiveness.

Rabbit anti-human CSF IgG. I. Characterization of anti-idiotype antibodies produced against MS CSF and detection of cross-reactive idiotypes in several MS CSF.

Serum from rabbits injected with IgG prepared from the CSF of patients with multiple sclerosis were rendered anti-idiotypic by adsorption on sequential columns of pooled human gamma-globulin, free light chains and free heavy chains. Adsorbed antisera precipitated between 15% and 45% of the autologous ligand and were inhibited by autologous CSF and serum and F(ab')2 fragments prepared from serum IgG. Idiotypic cross-reactivities were detected among the CSF IgG of several MS patients using three of these antisera. Two antisera demonstrated low levels of cross-reactivity with CSF IgG obtained from two of six heterologous MS patients. The third antiserum detected highly cross-reactive idiotypic determinants in the CSF IgG of two family members both having MS.

Identification of a unique idiotype in cerebrospinal fluid and serum of a patient with multiple sclerosis.

Anti-idiotypic antibodies were prepared in mouse ascites fluid against the CSF-IgG of a patient with multiple sclerosis. After adsorption with pooled human IgG, the ascites fluid antibodies precipitated 20% of labeled autologous CSF IgG. By using a competitive radioimmunoassay, less than one microgram of unlabeled CSF IgG produced 50% inhibition of binding autologous 125I-labeled CSF IgG, whereas 50 micrograms of normal HIgG was not inhibitory. The idiotype could be found in both serum and CSF IgG and persisted over a 5-year period. The absolute concentration of idiotype in the CSF varied somewhat but remained from 4 to 10 times greater than that of the serum. One of 14 heterologous MS CSF was found to contain small amounts of inhibitory protein; eight CSF from patients with other neurologic diseases did not contain the idiotype.

Identification of lactate dehydrogenase-elevating virus as the etiological agent of genetically restricted, age-dependent polioencephalomyelitis of mice.

The etiological agent of genetically restricted, age-dependent polioencephalomyelitis of mice (the ADPE agent) and several isolates of lactate dehydrogenase-elevating virus (LDV) were compared by biological, physical-chemical and antigenic criteria. The data indicate that the ADPE agent is a strain of LDV. Like LDV, the ADPE agent induced a selective elevation of plasma enzymes and splenomegaly in mice. The enzyme-elevating activity and the paralytogenic activity of the ADPE agent preparations were shown to belong to the same virus. The ADPE agent demonstrated LDV-like replication kinetics in vivo and in vitro. Moreover, the ADPE agent required primary mouse macrophages for in vitro replication, as does LDV. In turn, the LDV isolates induced a paralytic disease with ADPE-like lesions in the spinal cords of immunosuppressed C58 mice. However, the LDV isolates showed a stronger dependence on strain and age of mouse for the induction of paralysis than did the ADPE agent. The LDV isolates and the ADPE agent exhibited indistinguishable morphologies, buoyant densities, structural protein patterns, and virion ribonucleic acid sedimentation rates. Furthermore, they displayed strong antigenic cross-reactivity, as determined by cross-protection in vivo and by radioimmunoassay.

Circulating immune complexes in multiple sclerosis and other neurological diseases.

Circulating immune complexes were detected in 49% of sera from patients with multiple sclerosis, 45% of monosymptomatic optic neuritis, 45% of Guillain-Barré syndrome, and 15% of normal sera studied. The frequency of immune complexes in multiple-sclerosis sera was not correlated with the clinical status of the patients. Results with serial blood-samples were variable.

Polyoma virus strain with enhanced synthesis of capsid protein.

A study of the immunochemical characteristics and the synthesis of the capsid proteins of two polyoma virus strains (3049 and 1pS) was carried out to determine the mechanism responsible for the unique accumulation of those structural polypeptides in the cytoplasm of cells infected with the 3049 strain. Antisera prepared against disaggregated virus peptides and whole virus were used to measure the quantity of virus-specific antigens in cells infected by the two strains by using an indirect radioimmunoassay technique. The 3049-infected mouse embryo cells were found to contain several-fold more antibody-binding material than those infected with the 1pS strain. Furthermore, the cytoplasmic fraction of 3049-infected cells also contained more antibody-binding activity, supporting the hypothesis that the phenotype of the 3049 virus (cytoplasmic capsid protein) was a reflection of the increased synthesis of the capsid polypeptides.