V(L)IgMM transgene expression in DC via a GPI-anchor using a novel retroviral vector induces an in vitro autologous T-cell proliferation restricted to MHC class I molecules.
BACKGROUND
In order to improve the treatment and cure rate of multiple myeloma (MM), immunotherapy is a novel therapeutic approach. Since neoplastic plasma cells do not undergo further hypermutation, the variable region of the immunoglobulin light chain obtained from MM patients (V(L)IgMM) could serve as a tumor-specific antigen. In addition, dendritic cells (DC) have been identified as potent stimulators of an antigen-specific immune response. Here, we analyze in vitro autologous T-cell proliferation against the V(L)IgMM on presentation by retrovirally transduced dendritic cells.


METHODS
Expression of the tumor antigen in DC has been achieved using a novel retroviral vector containing NH(2)(34a.a)DAF-FLAG-V(L)IgMM-DAF(37a.a)COOH transgene. After cleavage of the amino- and carboxy-terminal hydrophobic domains of DAF, the FLAG-V(L)IgMM fusion gene is attached to the membrane via a GPI-anchor molecule. Thus, transduced cells can be detected using monoclonal anti-FLAG antibodies.


RESULTS
PI-PLC releases cell surface FLAG-antigen from transduced CD34(+) cells indicating that the vector directs the fusion protein to the cell surface via GPI-anchor. V(L)IgMM transgene expression in DC using our retroviral vector elicited an autologous T-cell proliferation restricted to MHC class I molecules. The proliferative response is more prominent in PMA-derived DC compared to cytokine-derived DC indicating that PMA-derived DC are more potent in activating autologous T-cell proliferation.


CONCLUSIONS
V(L)IgMM is an immunogenic peptide, which under certain conditions could provide a basis for a V(L)Ig-based immunotherapy in MM.
Department of Zoology, Faculty of Science, Ain Shams University, Cairo, Egypt.
Gamal
G
Ramadan
Reinhold E
RE
Schmidt
Jörg
J
Schubert
D000951:Antigens, Neoplasm / Q000235:genetics / Q000627:therapeutic use; D003713:Dendritic Cells / Q000276:immunology* / Q000378:metabolism / Q000637:transplantation; D005822:Genetic Vectors; D017261:Glycosylphosphatidylinositols; D015395:Histocompatibility Antigens Class I / Q000276:immunology; D006801:Humans; D007147:Immunoglobulin Light Chains / Q000235:genetics; D007135:Immunoglobulin Variable Region / Q000235:genetics; D016219:Immunotherapy, Adoptive / Q000379:methods; D008213:Lymphocyte Activation / Q000276:immunology*; D009101:Multiple Myeloma / Q000276:immunology / Q000628:therapy; D009194:Myeloma Proteins / Q000235:genetics* / Q000627:therapeutic use; D012190:Retroviridae / Q000235:genetics; D013601:T-Lymphocytes / Q000276:immunology; D014161:Transduction, Genetic; D019076:Transgenes
D000951:Antigens, Neoplasm; D017261:Glycosylphosphatidylinositols; D015395:Histocompatibility Antigens Class I; D007147:Immunoglobulin Light Chains; D007135:Immunoglobulin Variable Region; D009194:Myeloma Proteins