Preclinical development of hybrid cell vaccines for multiple myeloma

Abstract

Immunotherapy may provide alternative or supplementary treatment of multiple myeloma (MM). We propose that hybrid cells, formed by fusing professional antigen-presenting cells with malignant plasma cells, would induce immune responses capable of mediating tumour regression. The human B-lymphoblastoid cell line, HMy2, was fused in vitro with CD138+ bead-separated myeloma plasma cells from five patients with MM. The hybrid cell lines generated in these studies grew stably in tissue culture, and maintained their phenotypic and functional characteristics, providing self-renewing cell lines with potential for therapeutic vaccination. The hybrid cells stimulated allogeneic and autologous T-cell proliferative responses in vitro to a considerably greater degree than their respective parent myeloma plasma cells, and directly activated both CD4+ and CD8+ T-cell responses. The enhanced T-cell stimulation correlated with expression of CD80 on the hybrid cells, and was inhibited by CTLA4-Ig fusion protein. The hybrid cell lines expressed several tumour-associated antigens known to be expressed in myeloma. These data show that self-replicating cell lines with enhanced immunostimulatory properties and potential for therapeutic vaccination can be generated by in vitro fusion of ex vivo myeloma cells and B-lymphoblastoid cell lines.

Immunity to Growth Factor Receptor–Bound Protein 10, a Signal Transduction Molecule, Inhibits the Growth of Breast Cancer in Mice

“…Allogeneic class I determinants are strong immune adjuvants (32,33). To stimulate uptake of the vaccine by dendritic cells of the tumor-bearing host, and to ensure rejection, the fibroblasts (H-2 k ) were modified to express H-2K b determinants, allogeneic in C3H/He mice (LM-IL-2K b cells), as described previously (34,35).…”

Long-lived fusions of human haematological tumour cells and B-lymphoblastoid cells induce tumour antigen-specific cytotoxic T-cell responses in vitro

“…The EBV-associated B-LCL, HMy2 (Edwards et al 1982; gift from Prof. Alan Rickinson, Birmingham, UK), was used to generate LCL/tumour hybrid cell lines (Table 1) by fusion in vitro with a range of human haematological tumour cells, as described previously (Dunnion et al 1999;Walewska et al 2007). Following fusion, HAT and ouabain (both from Sigma, UK) were added to the culture medium at concentrations that were lethal to non-fused parent HMy2 cells or tumour cells respectively.…”

“…We have previously reported that the chemically selectable Blymphoblastoid cell line, HMy2 (Edwards et al 1982), can be fused in vitro with a range of tumour cells to generate long-lived hybrid cell lines that replicate continuously in tissue culture, and survive repeated freeze/thaw cycles in liquid nitrogen. The hybrid cell lines were phenotypically and functionally stable, showed enhanced immunogenicity in allogeneic mixed lymphocyte/tumour cell cultures (MLTC) compared with the parent tumour cells, and these responses were inhibited by addition of CTLA4-Ig to the cultures, indicating a role of CD80/CD86 costimulation in the enhanced allo-immunogenicity of the hybrid cell lines (Dunnion et al 1999;Walewska et al 2007). In this study, we demonstrate for the first time that HMy2-derived LCL/tumour hybrid cell lines induce tumour antigen-specific cytotoxic T lymphocyte (CTL) responses to a range of tumour associated antigens (TAAs), including MAGE-A1, NY-ESO-1, WT-1 and survivin, following in vitro stimulation of peripheral blood lymphocytes (PBL) from healthy individuals.…”

Vaccination of multiple myeloma: Current strategies and future prospects

“…Moreover, DCs fused with myeloma cells not only induced anti-tumor humoral and cellular immune responses but also extended the survival of tumor-established mice [99][100][101][102].…”