Disialoganglioside GD2 anti‐idiotypic monoclonal antibodies

Publisher Website
Google Scholar
Abstract
Disialoganglioside GD2 is widely expressed among neuroblas‐tomas, melanomas, small‐cell lung carcinoma, sarcomas and brain tumors. Immunity directed against this antigen may have anti‐tumor utility. Since GD2 is poorly immunogenic, anti‐idiotypic antibodies may serve as alternative tumor vaccines. Monoclonal antibody 3F8, a murine lgG3 specific for GD2, has shown excellent tumor‐targeting ability in vitro and in vivo. LOU/CN rats were immunized with 3F8 and their spleens were used in somatic‐cell hybridization, using Sp2/0, p3 and Y3 as fusion partners. Six anti‐idiotypic (anti‐id) MAbs (C2D8, ldio‐2, AIG4, C2H7, C4E4, A2A6) were selected based on their reactivity with 3F8 and non‐reactivity with murine lgG3 myelomas. Specificity of each anti‐id was demonstrated by using various ELISA: (i) lack of direct binding to solid phase myelomas and serum proteins; (ii) inability of other myelomas to inhibit anti‐id binding to 3F8; (iii) absence of cross‐reactivity of other myelomas to solid‐phase anti‐id; (iv) lack of inhibition by anti‐id of binding of other ganglioside antibodies to their antigens. Antigen specificity was further examined by inhibition of binding of 3F8 to GD2 on immuno‐thin‐layer chromatography, and by inhibition of 3F8 immunostaining of neuroblastoma cell lines. These 6 antibodies were demonstrated to be distinct, in view of their cross‐reactivity, fusion partners and relative strength of binding to 3F8. Anti‐GD2 antibodies were induced after immunization with these anti‐id antibodies in C57BI/6 mice. These rat anti‐3F8‐idiotypic antibodies with exquisite specificity for anti‐GD2 antibodies may be useful in vaccine construction.