Immunity to B16 melanoma in mice immunized with IL‐2‐secreting allogeneic mouse fibroblasts expressing melanoma‐associated antigens

Abstract

Co-presentation of weak tumour-associated antigens along with strongly immunogenic determinants leads to the development of an anti-tumour immune response in recipients syngeneic with the tumour. Tumour immunity develops in mice immunized with tumour cells modified by the introduction of cDNA for interleukin-2 (IL-2). Here, we report the anti-tumour response following immunization with an IL-2-secreting cell construct that expresses tumour-associated antigens, along with allogeneic major histocompatibility antigens. The construct was prepared by transfecting LM(TK-) mouse fibroblasts (H-2k) with genomic DNA from B16 melanoma cells syngeneic in C57BL/6J mice (H-2b). Transfectants expressing melanoma-associated antigens (MAA) were then infected with an expression-competent retroviral vector containing a cDNA specifying human IL-2. Cytotoxicity toward B16 cells was detected for as long as 5 months in both spleen and macrophage cell populations in C57BL/6J mice immunized with the IL-2-secreting cells. Mice immunized with non-IL-2-secreting, MAA-positive allogeneic cells developed melanoma immunity as well, but to a lesser extent. Immunity to 2 tumour-cell lines expressing the H-2d haplotype and to YAC-1 cells was detected in peritoneal macrophages, but not in spleen cells from C57BL/6J mice immunized with the cell construct, indicating that the response to B16 cells was only partially specific. C57BL/6J mice immunized with the IL-2-secreting cell construct survived significantly longer, following an injection of viable B16 cells, than mice in various control groups. The contribution of allogeneic antigens to the melanoma immunity was indicated by the failure of mice syngeneic with LM(TK-) cells to develop melanoma immunity following immunization with non-IL-2-secreting, MAA-positive cell constructs. The formation of IL-2 partially compensated for the lack of allogeneic antigens.

Anti-tumour activity against B16-F10 melanoma with a GM-CSF secreting allogeneic tumour cell vaccine

“…Allogeneic tumour cells vaccines have been investigated in pre-clinical models by several groups [13][14][15][16][17][18] with the finding that vaccination with completely allogeneic vaccine cells can induce a protective response against a subsequent challenge with live autologous tumour cells. So far the only evidence of T cell involvement in the response induced by the allogeneic vaccination was by in vitro CTL data [14][15][16] with the exception of Ashley and colleagues 13 who also demonstrated, as in the present study, that an allogeneic cell line (a pre-B cell line, 300.19), modified to express a specific model antigen (human epidermal growth factor receptor variant (EGFRvIII)), mediated anti-tumour activity against intracranial established tumours also expressing the model antigen (B16-F10 melanoma and 560 astrocytoma) through both CD4+ve and CD8+ve T cells.…”

“…So far the only evidence of T cell involvement in the response induced by the allogeneic vaccination was by in vitro CTL data [14][15][16] with the exception of Ashley and colleagues 13 who also demonstrated, as in the present study, that an allogeneic cell line (a pre-B cell line, 300.19), modified to express a specific model antigen (human epidermal growth factor receptor variant (EGFRvIII)), mediated anti-tumour activity against intracranial established tumours also expressing the model antigen (B16-F10 melanoma and 560 astrocytoma) through both CD4+ve and CD8+ve T cells. To our knowledge, there is no report of efficacy of GM-CSF secreting allogeneic whole tumour cell vaccine in both prevention and treatment of established tumours.…”

“…12 There are now several reports of allogeneic vaccine efficacy in animal models. [13][14][15][16][17][18] Morton and colleagues 19 have transferred this strategy to the clinic using unmodified allogeneic cells. However, early reports of allogeneic vaccines modified to secrete IL-2 have reported a limited response.…”

Application of interleukin-2–secreting syngeneic/allogeneic fibroblasts in the treatment of primary and metastatic brain tumors

“…The mice were maintained in the animal care facilities of the University Preparation of IL -2 -secreting mouse fibroblasts IL -2-secreting LM mouse fibroblasts (LM -IL -2 cells) were prepared as described previously. 12 In brief, the IL -2 gene was transduced into LM fibroblasts with the retroviral vector pZipNeoSVIL -2 (obtained originally from T. Taniguchi, Institute for Molecular and Cellular Biology, Osaka University, Osaka, Japan ). 18 The vector contained the human IL -2 gene and the neo r gene, both under control of the Moloney mouse leukemia virus long terminal repeat.…”

“…Human IL -2 has been found to be effective in this mouse model. 12 The neo r gene confers resistance to neomycin ( G418 ), an aminoglycoside antibiotic. 19 Helper-free stocks of recombinant retroviruses generated from the GP + env AM12 packaging cell line were used to transduce the LM cells.…”