ABSTRACT
Quantification of the peripheral nerve myelin glycoprotein P0 and antibodies to P0 is difficult due to insolubility of P0 in physiological solutions. We have overcome this problem by using the water-soluble recombinant form of the extracellular domain of P0 (P0-ED) and describe newly developed assays which allow detection and quantitation of P0 and antibodies to P0, in serum and cerebrospinal fluid (CSF). These sensitive and specific assays based on the ELISA technique were used to study humoral immune responses to P0 during experimental autoimmune ("allergic") neuritis (EAN). In order to establish these tests, monoclonal antibodies to different epitopes of rodent and human P0-ED were produced. A two-antibody sandwich-ELISA allowing quantitation of P0 (lower detection limit of 0.5 ng/ml or 30 fmol/ml) and an antibody-capture ELISA (lower detection limit 1 ng specific antibody/ml) to detect antibodies to P0 in serum and CSF were developed. EAN was induced in rats by active immunization with bovine myelin or the neuritogenic protein P2 or by adoptive transfer using P2 specific CD4 positive T cells. Serum and CSF were assayed for the presence of P0-ED and antibodies to P0-ED or P2. Antibodies to P0-ED were detected during active myelin-induced EAN, but not during P2-induced or adoptive transfer EAN. The anti-P0-ED antibodies in the CSF showed a correlation with disease activity. In contrast, in the same model antibodies to P2 persisted long after the disease ceased. No soluble P0-like fragments could be found in serum or CSF during any of the three types of EAN. We conclude that P0 may be a B-cell epitope in EAN. These findings warrant a screen for antibodies to P0-ED in human immune neuropathies.
Subject(s)
Autoantibodies/immunology , Autoimmune Diseases/immunology , Myelin Proteins/immunology , Neuritis, Autoimmune, Experimental/immunology , Animals , Antibodies, Monoclonal/immunology , Autoantibodies/blood , Autoantibodies/cerebrospinal fluid , Autoimmune Diseases/blood , Autoimmune Diseases/cerebrospinal fluid , Enzyme-Linked Immunosorbent Assay , Epitopes/immunology , Female , Immunotherapy, Adoptive , Myelin Basic Protein/administration & dosage , Myelin Basic Protein/immunology , Myelin P0 Protein , Myelin P2 Protein , Myelin Sheath/immunology , Neuritis, Autoimmune, Experimental/blood , Neuritis, Autoimmune, Experimental/cerebrospinal fluid , Neuritis, Autoimmune, Experimental/etiology , Rats , Rats, Inbred Lew/immunology , Sensitivity and SpecificityABSTRACT
The serotonin (5-HT) concentrations in the CSF and serum of the rabbits with experimental allergic neuritis (EAN) were determined. The relationships between the 5-HT concentrations and the rate of the specific lymphocyte transformation as well as that of the formation of the antimyelin antibody were investigated. The results indicated that after the rabbits were sensitized with myelin basic protein (MBP), the 5-HT levels in the CSF and serum of the rabbits with EAN increased. It was, therefore, considered that 5-HT might play a role in the inhibition of the lymphocyte transformation and the antibody production.
