Abstract
Vaccination with proteins mimicking GD2 that is highly expressed on neuroblastoma (NB) cells is a promising strategy in treatment of NB, a pediatric malignancy with poor prognosis. We previously showed efficacy of ganglidiomab in vivo, a murine anti-idiotype (anti-Id) IgG1. In order to tailor immune responses to variable regions, we generated a new human/mouse chimeric anti-Id antibody (Ab) ganglidiximab by replacing murine constant fragments with corresponding human IgG1 regions. DNA sequences encoding for variable regions of heavy (VH) and light chains (VL) were synthesized by RT-PCR from total RNA of ganglidiomab-producing hybridoma cells and further ligated into mammalian expression plasmids with coding sequences for constant regions of human IgG1 heavy and light chains, respectively. We established a stable production cell line using Chinese hamster ovarian (CHO) cells co-transfected with two expression plasmids driving the expression of either ganglidiximab heavy or light chain. After purification from supernatants, anti-idiotypic characteristics of ganglidiximab were demonstrated. Binding of ganglidiximab to anti-GD2 Abs of the 14.18 family as well as to NK-92tr cells expressing a GD2-specific chimeric antigen receptor (scFv(ch14.18)-zeta) was shown using standard ELISA and flow cytometry analysis, respectively. Ganglidiximab binding affinities to anti-GD2 Abs were further determined by surface plasmon resonance technique. Moreover, binding of anti-GD2 Abs to the nominal antigen GD2 as well as GD2-specific Ab-mediated cytotoxicity (ADCC, CDC) was competitively inhibited by ganglidiximab. Finally, ganglidiximab was successfully used as a protein vaccine in vivo to induce a GD2-specific humoral immune response. In summary, we report generation and characterization of a new human/mouse chimeric anti-Id Ab ganglidiximab for active immunotherapy against NB. This Ab may be useful to tailor immune responses to the paratope regions mimicking GD2 overexpressed in NB.
Highlights
NB is the most common extracranial solid tumor in early childhood
Since passive immunotherapy does not induce a long lasting immune response, there is a considerable interest in extending these studies into active immunotherapy
The newly generated chimeric anti-Id Ab ganglidiximab is composed of murine variable regions (VH, VL) derived from previously reported anti-Id ganglidiomab [17] and human instead of mouse IgG1 constant regions
Summary
NB is the most common extracranial solid tumor in early childhood. About 50% of patients show a high-risk NB phenotype, characterized by wide spread dissemination and poor longterm survival despite intensive multimodal treatments [1,2,3]. TAA-mimicking anti-Id Abs are used for protein vaccine development and successfully applied in a number of preclinical and clinical studies for a variety of solid tumors [14, 15]. For treatment of high-risk NB patients, an anti-Id Ab 1A7 bearing the internal image of GD2 was developed [16] and used as protein vaccine [1]. To provide unrestricted access for clinical development in Europe, we recently generated and characterized a murine anti-Id Ab ganglidiomab which paratopes mimic GD2. Vaccination of mice resulted in an induction of a GD2-specific humoral immunity [17] To further tailor this immune response induced by ganglidiomab to GD2-mimicking paratopes in prospective clinical trials, we generated a chimeric human/ mouse anti-Id Ab ganglidiximab by replacing murine constant regions with corresponding fragments of human IgG1
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
