ABSTRACT
Increasing evidence suggests a role for immunologic vaccination and therapy in the management of minimal residual myeloma. We have previously demonstrated a synergistic effect of combining the Th1 stimulating cytokine IL-12 with the co-stimulatory molecule CD80 in murine myeloma vaccination therapy. We reasoned that the efficacy of such treatment might be further improved by incorporating additional gene products which enhance the function of antigen presenting cells. Studies were therefore conducted with murine myeloma BM1 cells expressing Flt3L (membrane bound or soluble forms) or GM-CSF and the IL-12 x CD80 combination. Single agent and combined therapeutic approaches were explored. All gene-modified BM1 cells, except BM1/IL-12 x CD80, developed tumors when subcutaneously injected into BALB/c mice. As prophylactic tumor vaccines, the combined use of gene-modified BM1/sFlt3L+GM-CSF+IL-12 x CD80 was most effective, providing 100% protection against subsequent parental BM1 tumor challenge. By comparison, only partial protection was observed with any single gene-engineered tumor vaccine. Notably, IL-12 x CD80 coexpressing BM1 cell vaccines were the most effective therapeutic vaccine in a minimal disease model. Such protective vaccination was achieved by stimulation of lymphocyte proliferation and enhancement of cytotoxic lymphocyte activity.
Subject(s)
Cancer Vaccines/therapeutic use , Genetic Therapy , Immunotherapy , Multiple Myeloma/prevention & control , Adjuvants, Immunologic/metabolism , Adjuvants, Immunologic/therapeutic use , Animals , B7-1 Antigen/metabolism , B7-1 Antigen/therapeutic use , Cancer Vaccines/metabolism , Cell Division , Combined Modality Therapy , Cytotoxicity, Immunologic , Female , Gene Transfer Techniques , Granulocyte-Macrophage Colony-Stimulating Factor/metabolism , Granulocyte-Macrophage Colony-Stimulating Factor/therapeutic use , Humans , Interleukin-12/metabolism , Interleukin-12/therapeutic use , Ligands , Membrane Proteins/metabolism , Membrane Proteins/therapeutic use , Mice , Mice, Inbred BALB C , Mice, SCID , Multiple Myeloma/immunology , Multiple Myeloma/therapy , Retroviridae/genetics , Spleen/immunology , Survival Rate , T-Lymphocytes/immunology , T-Lymphocytes/metabolism , T-Lymphocytes, Cytotoxic/immunology , Tumor Cells, Cultured , VaccinationABSTRACT
SH3 and SAM domains are protein interaction motifs that are predominantly seen in signaling molecules, adaptors, and scaffold proteins. We have identified a novel family of putative adaptor genes that includes HACS1. HACS1 encodes a 441 amino acid protein that is differentially expressed in hematopoietic cells and has restricted expression in human tissues. Its SH3 domain is most similar to the same motif in Crk and its SAM domain shares homology with a family of uncharacterized putative scaffold and adaptor proteins. HACS1 maps to human chromosome 21q11.2 in a region that is frequently disrupted by translocation events in hematopoietic malignancies. Polyclonal antibodies against HACS1 recognized a 49.5 kDa protein whose mRNA is expressed in human immune tissues, bone marrow, heart, lung, placenta and brain. Cell lines and primary cells from acute myeloid leukemias and multiple myeloma patients express HACS1. Immunostaining and cellular fractionation studies localized the HACS1 protein predominantly to the cytoplasm.