Insight into the potential for DNA idiotypic fusion vaccines designed for patients by analysing xenogeneic anti‐idiotypic antibody responses

Abstract

SUMMARYDNA vaccines induce immune responses against encoded proteins, and have clear potential for cancer vaccines. For B-cell tumours, idiotypic (Id) immunoglobulin encoded by the variable region genes provides a target antigen. When assembled as single chain Fv (scFv), and fused to an immunoenhancing sequence from tetanus toxin (TT), DNA fusion vaccines induce anti-Id antibodies. In lymphoma models, these antibodies have a critical role in mediating protection. For application to patients with lymphoma, two questions arise: first, whether pre-existing antibody against TT affects induction of anti-scFv antibodies; second, whether individual human scFv fusion sequences are able to fold consistently to generate antibodies able to recognize private conformational Id determinants expressed by tumour cells. Using xenogeneic vaccination with scFv sequences from four patients, we have shown that pre-existing anti-TT immunity slows, but does not prevent, anti-Id antibody responses. To determine folding, we have monitored the ability of nine DNAscFv-FrC patients' vaccines to induce xenogeneic anti-Id antibodies. Antibodies were induced in all cases, and were strikingly specific for each patient's immunoglobulin with little cross-reactivity between patients, even when similar V H or V L genes were involved. Blocking experiments with human serum confirmed reactivity against private determinants in 26 -97% of total antibody. Both immunoglobulin G1 (IgG1) and IgG2a subclasses were present at 1 . 3 : 1-15 : 1 consistent with a T helper 2-dominated response. Xenogeneic vaccination provides a simple route for testing individual patients' DNAscFv-FrC fusion vaccines, and offers a strategy for production of anti-Id antibodies. The findings underpin the approach of DNA idiotypic fusion vaccination for patients with B-cell tumours.

Hairy cell leukemias with unmutated IGHV genes define the minor subset refractory to single-agent cladribine and with more aggressive behavior

“…26 The expressed tumor IGHVDJ, IGKVJ, and IGLVJ transcripts were amplified by reverse-transcript polymerase chain reaction, cloned, and sequenced, as described. 22,26,27 The cloned sequences were aligned to the ImMunoGeneTics database to identify the tumor transcript and determine tumor gene usage and homology. 28 Sequences with more than or equal to 98% homology to germline were defined as "UM."…”

Control of human mesothelin-expressing tumors by DNA vaccines

“…For example, the employment of xenogeneic antigens for the DNA vaccine development has been shown to effectively break tolerance in some cancer models. [19][20][21][22][23][24][25][26][27][28] Other strategies that are capable of breaking tolerance include the employment of suicidal DNA vectors and bacterial vectors. [29][30][31][32][33] Thus, the use of tolerance-breaking methods in conjunction with therapeutic strategies targeting Hmeso may overcome this problem.…”

Synergistic Effect of Dendritic Cell Vaccination and Anti-CD20 Antibody Treatment in the Therapy of Murine Lymphoma

“…Other immunization strategies include vaccination by DCs loaded with apoptotic tumor cells or lysates 13 and DNA vaccination with constructs encoding variable heavy and light chain Ig sequences. 14,15 Results from preclinical and clinical studies suggest that both humoral and cellular immune responses may be important for the efficacy of Id vaccines. 7,11,12,16 Rituximab depletes malignant and normal B cells, hence prevents generation of humoral immune responses after active immunization.…”