Cross-reactive idiotypy in cerebrospinal fluid immunoglobulins in multiple sclerosis

The presence of oligoclonal bands in cerebrospinal fluid (CSF) in multiple sclerosis (MS) indicates a restricted heterogeneity of immunoglobulin (Ig). The portion of myelin basic protein encompassing residues 80-96 contains epitopes frequently recognized by T and B cells of MS patients. To define further this restricted heterogeneity and to direct further efforts to identify an antigenic target of CSF oligoclonal bands, the presence of idiotope (Id)-bearing antibodies sharing an Id with a murine monoclonal antibody to myelin basic protein peptide 80-89 was examined in the CSF of MS patients. CSF samples from 57 patients with clinically definite MS and 45 patients with other neurological diseases were standardized for amount of IgG and analyzed by immunoblotting for detection of Id-bearing antibodies. Id-bearing Ig was detected in the CSF of 79% of MS patients and 16% of other neurological disease patients. Further statistical analysis revealed an 84% specificity, an 86% positive predictive value, and a 76% negative predictive value of the test. The probability that a positive screening result indicated MS was 81%. Thus, antibodies containing a cross-reactive Id are present preferentially in the CSF of patients with MS compared with those with other neurological diseases. An immune network that has limited V region gene usage likely exists in the CSF and central nervous system of patients with MS and may provide evidence about antigens relevant to the pathogenesis of MS.

A cross-reactive anti-myelin basic protein idiotope in cerebrospinal fluid cells in multiple sclerosis

We wanted to find evidence of antibody to myelin basic protein (MBP) in patients with MS by detecting their shared usage of immunoglobulin genes. As demonstrated by the idiotopes (i.d.) of murine monoclonal antibody to peptides of MBP, there is limited use of the variable (V) region immunoglobulin genes for the immune response in mice to this encephalitogenic protein. Cross-reactive Ids have been detected across different murine strains and shared by T and B cells. One cross-reactive Id, designated as 845D3 Id, is located on the V region of kappa light chains of two murine monoclonal antibodies, one to MBP peptide 80-89 and the other to MBP peptide acetyl 1-9. To examine the occurrence of 845D3 Id in MS, we used the V region of a light chain (VL) of one of the monoclonal antibodies to probe the VL genes expressed in B cells in CSF of 50 patients (31 MS and 19 non-MS). The VL genes expressed in B cells found in CSF were amplified by polymerase chain reaction using universal human V-region primers. The 845D3 Id probe detected the Id+ V region in the CSF of 14 of 31 MS patients, 1 of 9 patients with other neurologic diseases, and 1 of 10 non-neurologic patients. The gene product was more common in but not restricted to CSF with oligoclonal bands. The presence in CSF of MS patients of a cross-reactive Id to different MBP peptides is indicative of an immune response to this encephalitogenic myelin protein in a segment of MS patients. These findings are also evidence for limited usage of V-region Ig genes in the immune response of humans to MBP and the possible importance of an Id network for MBP in demyelinating disease.

Comparison of properties of murine monoclonal anti-idiotypic antibodies generated with idiotype-bearing monoclonal antibodies to myelin basic protein peptides or their complementary peptides

The present study was undertaken to compare the features of monoclonal antibody (mAb) anti-idiotope (Id) induced by complementary peptides, synthesized on the basis of inverted hydropathy for a myelin basic protein (MBP) peptide, or by conventional methodology using Id-bearing antibodies to the same MBP peptide as immunogen. The six reagents studied consisted of mAbs reactive with MBP peptide acetyl 1-9 and MBP peptide 80-89 and anti-Id reagents against these two mAbs prepared by either the complementary peptide or the conventional approach. ELISA, immunoblotting, immunoinhibition of hybridoma cell production of Id-bearing mAb to MBP, and FACS indicated that the anti-Ids generated by either technique were similar although existing in a range reflecting biologic phenomena. mAbs anti-Id prepared by either method continued to show an IgM isotype preference, possibly related to technical considerations, and continued to recognize a cross-reactive Id on the kappa light chain of the mAbs to MBP peptides acetyl 1-9 and 80-89. There was no indication that the anti-Ids prepared by the complementary peptide approach were restrictive or selective in a manner different from those made by the conventional approach.