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A sensitive gel filtration radioimmunoassay was used to test for antibodies to the basic protein of myelin, the antigen of experimental autoimmune encephalomyelitis, in serum and cerebrospinal fluid (CSF) of patients with multiple sclerosis (MS) and other diseases. Sera and CSF from patients with MS gave results similar to those for controls including subjects with various neurological diseases Binding of 125I-basic protein by seven-fold concentrated CSF was shown to be due to α-globulin. Free basic protein, as a possible auto-immunogen, was sought in the serum and seven-fold concentrated CSF of patients with MS and controls by competitive inhibition in the radioimmunoassay, but none was demonstrable. if an immunological mechanism is to be invoked in the initiation of destruction of the basic protein of myelin in MS, then either pathogenic 'antibody' must be absorbed in vivo to the target antigen in the central nervous system or the initiating events must be mediated entirely by sensitized lymphocytes. [ABSTRACT FROM AUTHOR]

A sensitive gel filtration radioimmunoassay was used to test for antibodies to the basic protein of myelin, the antigen of experimental autoimmune encephalomyelitis, in serum and cerebrospinal fluid (CSF) of patients with multiple sclerosis (MS) and other diseases. Sera and CSF from patients with MS gave results similar to those for controls including subjects with various neurological diseases Binding of 125I-basic protein by seven-fold concentrated CSF was shown to be due to α-globulin. Free basic protein, as a possible auto-immunogen, was sought in the serum and seven-fold concentrated CSF of patients with MS and controls by competitive inhibition in the radioimmunoassay, but none was demonstrable. If an immunological mechanism is to be invoked in the initiation of destruction of the basic protein of myclinin MS, then either pathogenic `antibody' must be absorbed in vitro to the target antigen in the central nervous system or the initiating events must be mediated entirely by sensitized lymphocytes. [ABSTRACT FROM AUTHOR]

Splenic lymphocytes from guinea-pigs injected with the basic protein of myelin (BPM) in Freund's complete adjuvant (FCA) were shown by autoradiography to contain a significantly (P<0.01) greater proportion of lymphocytes binding 125I-BPM than splenic lymphocytes from control guinea-pigs injected only with FCA; these in turn contained more than splenic lymphocytes from normal guinea-pigs. Splenic lymphocytes from guinea-pigs injected with a synthetic eleven amino acid peptide (containing the main encephalitogenic determinant, for guinea-pigs, of BPM) in FCA did not contain more lymphocytes binding 125IBPM than control suspensions from guinea-pigs injected only with FCA. Binding ability was confered on splenic lymphocytes of normal guinea-pigs, and especially on splenic lymphocytes of guinea-pigs injected with FCA, when the cells were held with guinea-pig antisera to BPM, the binding capacity of which was present in the IgG2 subclass. In contrast, splenic lymphocytes from Lewis rats after injection of BPM of rat lacked the ability to bind 125I-BPM of rat, as did splenic lymphocytes from normal rats held with potent rat antiserum to BPM of rat. Our results show, for the guinea-pig, that antibody attaches in vitro to the lymphocyte surface as antigen receptor, and, for this species at least, may be an important cause in vivo of the presence of antigen-binding cells after injection of antigen. [ABSTRACT FROM AUTHOR]

The binding capacity of human and rabbit serum and serum fractions for [125I]encephalitogenic basic protein, extracted from human brain, were determined by gel-filtration radioimmunoassay. Strong binding was effected by the γ-globulin fraction or whole serum of a rabbit with experimental allergic encephalitis, and was completely inhibited by excess of unlabelled encephalitogenic basic protein but not by large amounts of lysozyme. Smaller amounts of encephalitogenic basic protein were bound by normal rabbit and human serum, and by the serum of a patient with multiple sclerosis: the α2-macroglobu1in fraction was responsible for this, and complete inhibition was effected by excess unlabelled encephalitogenic basic protein but only partial inhibition by excess lysozyme. It is concluded that binding detected in some radioimmunoassay systems may not represent a classical antigen-antibody reaction, and it is suggested that α-macroglobulins may, by binding in vivo, be of importance in experimental allergic encephalomyelitis and, by analogy, in human demyelinating disease. [ABSTRACT FROM AUTHOR]