Sensitization of cerebrospinal fluid and peripheral blood lymphocytes to myelin basic protein in multiple sclerosis

A chemiluminescence assay to detect antibodies to brain surface antigens in human sera

A chemiluminescence assay was developed based on the interaction between antibodies binding to the surface of living brain cells in culture and macrophages. Such interaction leads to production of reactive oxygen radicals which can be measured by a chemiluminescence assay. This assay was used to detect anti brain antibodies in serum samples from humans with various neurological diseases. Such antibody activity was found in a high proportion of these patients. Subsequent experiments with purified IgG fractions and corresponding F(ab')2 fragments showed that the observed reactions were highly specific. It was concluded that the chemiluminescence assay is a sensitive and useful technique to detect autoantibodies in neurological diseases.

Myelin basic protein-specific T lymphocytes in multiple sclerosis and controls: precursor frequency, fine specificity, and cytotoxicity

A panel of 90 myelin basic protein (MBP)-specific T-cell lines were derived from peripheral blood of eight patients with multiple sclerosis and four normal subjects. The precursor frequency of MBP-reactive T cells in peripheral blood mononuclear cells ranged from 10(-7) to 9 x 10(-7) (mean, 6.7 x 10(-7)) in the group of patients with multiple sclerosis and from 0.5 x 10(-7) to 9.8 x 10(-7) (mean, 5.6 x 10(-7)) in the control subjects. This difference between the two groups was not statistically significant (p greater than 0.1). These T-cell lines expressed exclusively CD3+CD4+CD8- phenotypes and were restricted predominantly by HLA-DR molecules. When tested with fragments and synthetic peptides of human MBP, these MBP-specific T-cell lines (45 lines for each group) displayed a limited heterogeneous pattern with a biased recognition to peptide 84-102 and the C-terminal peptide 149-171. The reactivity to the 84-102 region of MBP was associated with the HLA-DR2, DRw15 (DRw15,2) haplotype, whereas the recognition to peptide 149-171 did not correlate with a particular HLA-DR allele(s). Furthermore, the majority of T-cell lines (greater than 75%) were found to exhibit substantial cytotoxic activity against MBP-coated target cells, but showing no significant difference between these two groups. This MBP-dependent cytotoxicity was not associated with epitope specificities of the T-cell lines tested.

Preferential peptide specificity and HLA restriction of myelin basic protein-specific T cell clones derived from MS patients

A panel of 17 myelin basic protein (MBP)-specific T lymphocyte clones were generated from four multiple sclerosis (MS) patients. All T cell clones expressed CD4 phenotype and 14 clones exhibited substantial cytotoxic activity on MBP-coated target cells. T cell recognition sites of the clones on human MBP were identified by using MBP fragments and synthetic peptides. Despite the fact that at least three epitopes were defined, these T cell clones displayed a striking bias to the C-terminal peptide 149-171 independent of differences in HLA-DR and DQ expression. In addition, the T cell responses of the clones appeared to be restricted by HLA-DR molecules irrespective of peptide specificities. The present study suggests an immunodominant property of the C-terminal peptide for HLA-DR-restricted T cell responses to MBP. However, its association with encephalitogenicity in humans and its potential pathologic importance in MS await further clarification.

In vitro functional blocking of myelin basic protein-specific cytolytic human T lymphocyte clones by immunosuppressive drugs and monoclonal antibodies

The in vitro effects of cyclosporin A, prednisolone, and anti-CD4 monoclonal antibody WW.T4 on myelin basic protein-specific human CD4+ cytolytic T lymphocyte clones were studied. Functional assays of antigen-specific proliferation, induction of specific lysis, cytolysis itself, and interferon-gamma production were done. Prednisolone decreased secretion of interferon-gamma by the clones and blocked specific proliferation; the latter could, however, be overcome by the addition of exogenous interleukin 2. It did not influence cytolytic properties. In contrast, cyclosporin A and WW.T4 blocked the four antigen-specific functions of the autoimmune myelin basic protein-specific human T cell clones measured.

T cell lines established from multiple sclerosis cerebrospinal fluid T cells using human retroviruses

Cerebrospinal fluid (CSF) lymphocytes from patients with multiple sclerosis (MS) were transformed with human T cell leukemia/lymphoma virus (HTLV I and HTLV II) and the resulting cell lines characterized by cell surface phenotyping and functional assessment. The lines were predominantly of the CD4 helper/induce phenotype although the HTLV II lines contained 10-20% CD8+ cells. The lines appeared to be activated cells; the majority were TA1+, HLA-DR+, and TAC+ (CD25+). Interestingly, they were OKT10- (CD38-). Functionally, the lines contained no natural killer (NK) activity and were modestly cytotoxic in the antibody-dependent cellular cytotoxicity (ADCC) assay. They were poor proliferative responders to antigens and mitogens though the HTLV II lines did respond to interleukin 2 (IL2). The HTLV I lines were either nonresponsive to or were suppressed by IL2. Early passages of two of the lines produced IL2 but this was lost as the cells were passed in culture. The cell lines were capable of either directly or indirectly suppressing pokeweed mitogen (PWM)-driven immunoglobulin production by normal B cells. In addition, the lines were capable of producing gamma-interferon (IFN-gamma), lymphotoxin (LT), an interleukin 1 (IL1)-like factor, glial growth promoting factor (GGPF), and IL6. The advantage of these lines over clones or cell lines developed using other techniques is their growth in the absence of feeder layers or IL2 and their ability to be cloned and to grow in culture indefinitely.

Myelin basic protein-specific CD4+ cytolytic T-lymphocyte clones isolated from multiple sclerosis patients

In the present report we describe the isolation and characterization of stable, long-term, human T-lymphocyte clones specific for myelin basic protein (MBP) from multiple sclerosis (MS) patients. Isolation of these clones appeared possible only by seeding peripheral blood mononuclear cells into a limiting dilution microculture system containing MBP, autologous irradiated cells and Interleukin-2 (IL-2), thereby minimizing effects of putative suppressor cell populations. All clones obtained were of the CD4+ phenotype. The majority was capable of MBP-specific cytolysis, tested with 51Chromium-labeled autologous Epstein-Barr virus (EBV)-transformed B-cells, coated with MBP, as targets. A few other clones had natural killer (NK) function. All clones produced Interleukin-2 (IL-2) upon adequate stimulation.

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.

Phenotypic markers and functional characteristics of T lymphocyte clones from cerebrospinal fluid in multiple sclerosis

We have recently developed a technique for direct expansion of human T lymphocyte clones from cerebrospinal fluid (CSF) of patients with acute infections of the central nervous system (CNS). In the present study, T lymphocyte clones were established directly from the CSF of 4 patients with multiple sclerosis by limiting dilution in the presence of T cell growth factor and irradiated feeder cells. In 3 patients the CSF was obtained during an exacerbation of their disease. Cloning efficiencies ranged between 4 and 6%. About 40 clones per patient were available for surface marker analysis and functional studies. Typing of the clones for membrane antigens revealed the following results: 75-100% had the OKT4+8- and 0-25% the OKT4-8+ phenotype. Only one clone expressed both surface markers. When tested for PHA-dependent cytotoxicity, all OKT8+ clones and about 50% of the OKT4+ clones were found to express cytotoxic activity. Studies on the proliferative response showed that all OKT4+ and the majority of OKT8+ clones were capable of TCGF-independent, mitogen-induced proliferation. Screening of the clones for specific reactivity against a panel of antigens including measles virus, mumps virus, Epstein-Barr virus and myelin basic protein (MBP) did not reveal significant specific reactivity.