Passive immunity to murine plasmacytoma by rabbit antiidiotypic antibody to myeloma protein

Vaccination of multiple myeloma patients with idiotype-pulsed dendritic cells: immunological and clinical aspects

Multiple myeloma (MM) is characterized by a clonal proliferation of malignant plasma cells in the bone marrow secreting a monoclonal immunoglobulin (paraprotein) with specific antigenic determinants, the idiotype (Id), which can be regarded as a tumour-associated antigen (TAA). In order to analyse the impact of a dendritic cell (DC)-based vaccine, 11 patients with advanced MM were treated with CD34 stem cell-derived dendritic cells that were pulsed with Id peptides. Subsequently, the patients received three boost immunizations every other week with a combination of Id and granulocyte-macrophage colony-stimulating factor (GM-CSF) (nine patients) or with Id peptide-pulsed dendritic cells again (two patients). The treatment was well tolerated with no side-effects. The present clinical study was a proof of concept analysis of dendritic cell-based vaccines in MM. The capacity of the dendritic cells to activate idiotype-specific T cells was verified by in vitro stimulation experiments before the vaccination therapy. Immunological effects of the Id vaccination were analysed by monitoring changes in anti-idiotype antibody titres and idiotype-specific T-cell activity. After vaccination, three out of 10 analysed patients showed increased anti-idiotype antibody serum titres, indicating the induction of an idiotype-specific humoral immune response. The idiotype-specific T-cell response analysed by ELISpot was increased in four out of 10 analysed patients after vaccination, and one patient had a decreased plasma cell infiltration in the bone marrow. In conclusion, five out of 11 patients showed a biological response after vaccination. Thus, our data indicate that immunotherapy with Id-pulsed DCs in MM patients is feasible and safe. DC generated from CD34+ progenitor cells can serve as a natural adjuvant for the induction of clinically relevant humoral and cellular idiotype-specific immune responses in patients suffering from advanced MM.

Idiotype Immunization Combined With Granulocyte-Macrophage Colony-Stimulating Factor in Myeloma Patients Induced Type I, Major Histocompatibility Complex–Restricted, CD8- and CD4-Specific T-Cell Responses

Idiotypic structures expressed on the myeloma Ig protein might be regarded as a tumor-specific antigen. Five patients with IgG myeloma were immunized with the purified serum M-component by repeated intradermal injections together with soluble granulocyte-macrophage colony-stimulating factor (GM-CSF). All patients developed an idiotype (Id)-specific T-cell immunity, defined as blood T cells predominantly secreting interferon-γ (IFN-γ) and interleukin-2 (IL-2) (type I cells). Id-specific DNA synthesis was induced in one patient. Delayed-type hypersensitivity against the Id was not evoked. The specific IFN-γ/IL-2 T-cell response was inhibited (46% to 100%) by a major histocompatibility complex (MHC) class I monoclonal antibody (MoAb) in all five patients. A 5% to 37% inhibition by an MHC class II MoAb was seen in four patients. CD4+ as well as CD8+ T cells enriched by magnetic microbeads contained Id-specific cells. The T cells recognized peptides corresponding to the complementarity-determining regions 1, 2, and 3 of the heavy chain of the Id. There was a transient rise of B cells producing IgM anti-idiotypic antibodies in all patients. The results indicate that immunization of myeloma patients using the autologous M-component and soluble GM-CSF may evoke an Id-specific predominantly MHC class I–restricted type I T-cell response.

Idiotype Immunization Combined With Granulocyte-Macrophage Colony-Stimulating Factor in Myeloma Patients Induced Type I, Major Histocompatibility Complex–Restricted, CD8- and CD4-Specific T-Cell Responses

Idiotypic structures expressed on the myeloma Ig protein might be regarded as a tumor-specific antigen. Five patients with IgG myeloma were immunized with the purified serum M-component by repeated intradermal injections together with soluble granulocyte-macrophage colony-stimulating factor (GM-CSF). All patients developed an idiotype (Id)-specific T-cell immunity, defined as blood T cells predominantly secreting interferon-γ (IFN-γ) and interleukin-2 (IL-2) (type I cells). Id-specific DNA synthesis was induced in one patient. Delayed-type hypersensitivity against the Id was not evoked. The specific IFN-γ/IL-2 T-cell response was inhibited (46% to 100%) by a major histocompatibility complex (MHC) class I monoclonal antibody (MoAb) in all five patients. A 5% to 37% inhibition by an MHC class II MoAb was seen in four patients. CD4+ as well as CD8+ T cells enriched by magnetic microbeads contained Id-specific cells. The T cells recognized peptides corresponding to the complementarity-determining regions 1, 2, and 3 of the heavy chain of the Id. There was a transient rise of B cells producing IgM anti-idiotypic antibodies in all patients. The results indicate that immunization of myeloma patients using the autologous M-component and soluble GM-CSF may evoke an Id-specific predominantly MHC class I–restricted type I T-cell response.

Prospects for the treatment of B cell tumors using idiotypic vaccination

Manipulation of the immune system in order specifically to attack autologous tumor cell has been a distant goal, largely due to the poor definition of tumor-associated antigens. By focussing on B cell lymphomas which express a molecularly defined clonal marker, the idiotypic immunoglobulin, it has been possible to generate autologous anti-idiotypic responses which suppress individual tumors. Studies of the components of these responses are providing insight into host effector mechanisms which can be activated against tumors, and also into the many strategies adopted by the target cells in order to avoid such attack. Promising results in various animal models where tumor bearers can be treated by idiotypic immunization have led to the point where application of this approach to the treatment of certain categories of human B cell lymphoma can be considered.