Monoclonal Antibodies Raised Against the Idiotype of the Murine B Cell Lymphoma, BCL₁Act Primarily with Heavy Chain Determinants

Abstract

Anti-idiotypic antibodies can be used as probes to distinguish neoplastic cells from their normal counterparts. In addition they have been used in the passive therapy of B cell tumors. In this report we describe a panel of 7 rat monoclonal antibodies raised against idiotypic determinants carried by the IgM molecule of the BCL1 lymphoma. The majority (6/7) of these antibodies recognize private idiotypic determinants that are carried on the isolated mu heavy chain of the molecule, and do not require the lambda chain for reactivity. This is unusual for antibodies raised against the idiotype of the whole immunoglobulin molecule, which normally require both chains for reactivity. The antibodies do not, however, bind peptides corresponding to the complementarity determining regions of the mu heavy chain of BCL1. The antibodies perform well in complement mediated cytotoxicity, and, in at least one case, are effective in the passive immunotherapy of BCL1 lymphoma.

Anti-idiotypic DNA vaccines for lymphoma immunotherapy require the presence of both variable region genes for tumor protection

“…12 This observation prompted us to investigate the possibility of using VH gene immunization for active immunotherapy of lymphoma. Two previous reports had shown that anti-V region antibodies can be raised in mice by immunizing with human VK and VH gene constructs.…”

“…Earlier studies showing that monoclonal Abs against the BCL1 idiotype act primarily with heavy chain determinants, 12 prompted us to investigate the efficacy of a second construct in which the BCL1 VL gene was deleted. Since for both protein and DNA immunizations the addition of the granulocyte-monocyte colony-stimulating factor (GM-CSF) has been shown to improve vaccine efficacy, [13][14][15][16] we co-administered a GM-CSF encoding vector with each of the antigen-containing plasmids.…”

Anti-idiotypic antibodies induced by genetic immunisation are directed exclusively against combined VL/VH determinants

“…Positive clones showing comparable expression levels for each construct were selected ( Figure 2b). Proper display of the Id BCL1 on Sp2/0 cells transfected with ⑀-mBCL1 was demonstrated by flow cytometry using two specific reagents: an anti-Id BCL1 mAb (10/4A12) 21 and the anti-Id serum raised by pBCL1 ( Figure 2c). In addition, since mAb 10/4A12 binds to V H of BCL1 21 we tested it on the V L 6C6 /V H BCL1 chimera.…”

“…Proper display of the Id BCL1 on Sp2/0 cells transfected with ⑀-mBCL1 was demonstrated by flow cytometry using two specific reagents: an anti-Id BCL1 mAb (10/4A12) 21 and the anti-Id serum raised by pBCL1 ( Figure 2c). In addition, since mAb 10/4A12 binds to V H of BCL1 21 we tested it on the V L 6C6 /V H BCL1 chimera. As shown in Figure 2c, mAb 10/4A12 stained SP2/0 transfected cells, indicating that V H BCL1 is also properly displayed in the context of a non-parental Id.…”

“…mAb 10/4A12 is a rat mAb specific for V H of BCL1. 21 Staining with mAb 10/4A12 was performed by incubation for 1 h (1:200) followed by a FITC-conjugated goat anti-rat IgG (Kirkegaard and Perry). Fluorescence analysis was performed with a FACScalibur (Becton Dickinson, San Jose, CA, USA).…”