Humoral response to vaccination with interleukin-2-expressing allogeneic neuroblastoma cells after primary therapy

Background. Immunotherapy using cytokine-expressing tumor cells has shown p romise as an anticancer strategy. We have recently begun a trial of interle ukin-2 (IL-2) gene-modified allogeneic neuroblastoma cells administered in a sequence of eight injections to patients with high-risk neuroblastoma fol lowing completion of primary therapy. Six patients to date have completed t reatment. Procedure. We examined humoral responses to the immunizing cell l ine and, when available, to the patients' autologous tumor cells using an i n vitro binding assay. Results. Five of six patients developed a rise in an titumor antibodies to the immunizing neuroblastoma cell line following vacc ination. Two of these patients had autologous tumor available; both demonst rated a humoral response to these cells as well. Conclusions. Our results d emonstrate that vaccination with IL-2-expressing allogeneic tumor cells aft er intensive primary therapy can elicit a humoral response to the immunizin g line. These antibodies are cross-reactive with the patients' own tumor ce lls in the two cases in which autologous cells were available. This suggest s that different patients' tumors may share common antigens that can be exp loited in immunotherapy strategies and supports the continued exploration o f allogeneic tumor cells as tumor vaccines. Med. Pediatr. Oncol. 35: 712-71 5, 2000. (C) 2000 Wiley-Liss, Inc.