Alteration of the humoral immune response against muscle acetylcholine receptor by timed administration of alpha(1----3)dextran

Monoclonal antibody against alpha(1----3) dextran transfers suppression of the immune response to the acetylcholine receptor

Previous studies have demonstrated that immunization of BALB/c mice with alpha(1----3) dextran (Dex) is accompanied by a reduction in the subsequent immune response to the acetylcholine receptor (AChR), depending on the timing of the Dex administration relative to AChR challenge. Here, we report that suppression of the anti-AChR response can be transferred by a monoclonal antibody, known as DX2, which is specific for Dex. Serum transfer experiments have also supported the notion that antibody is important for this effect. In addition, two new idiotypic markers have been defined that are expressed mainly by antibodies against Dex, including DX2. The anti-idiotypic reagents (Sh135 and EB5) are derived from the immune response to the AChR. A human monoclonal antibody which binds to Dex (SR 11) resembles the BALB/c antibodies that are involved in the suppression of the anti-AChR response. These findings emphasize the functional relevance of the AChR-Dex network not only for the BALB/c immune response to the AChR, but also for humans with the autoimmune disease, myasthenia gravis.