Therapeutic vaccine for lymphoma

Impact of Immunotherapy on CD4 T Cell Phenotypes and Function in Cancer

Immunotherapy has become a standard treatment in many cancers and it is based on three main therapeutic axes: immune checkpoint blockade (ICB), vaccination and adoptive cell transfer (ACT). If originally these therapies mainly focused on exploiting CD8 T cells given their role in the direct elimination of tumor cells, increasing evidence highlights the crucial role CD4 T cells play in the antitumor immune response. Indeed, these cells can profoundly modulate the tumor microenvironment (TME) by secreting different types of cytokine or by directly eliminating cancer cells. In this review, we describe how different CD4 T cell subsets can contribute to tumor immune responses during immunotherapy and the novel high-throughput immune monitoring tools that are expected to facilitate the study of CD4 T cells, at antigen-specific and single cell level, thus accelerating bench-to-bed translational research in cancer.

Synergistic effect of dendritic cell vaccination and anti-CD20 antibody treatment in the therapy of murine lymphoma

Indolent B-cell lymphomas are characterized by repeated remissions and relapses with most patients eventually dying of the disease. Although combination treatments with chemotherapy and the anti-CD20 antibody rituximab improved duration of remissions and overall survival, the disease is essentially incurable. Thus, novel therapeutic approaches are needed. One such approach is active immunization with dendritic cells (DCs). Given that rituximab depletes patients of normal B cells, optimal vaccination strategies for rituximab-treated patients require induction of effector T cells. We have previously demonstrated in a murine model that idiotype (Id)-keyhole limpet hemocyanin-pulsed DCs induced Id-reactive CD8 T cells and protection against tumor challenge in the absence of anti-Id antibodies. On the basis of these results, we investigated vaccination in a therapeutic model, in which mice carrying advanced tumors of the highly aggressive 38C-13 lymphoma were treated with chemotherapy and anti-CD20 antibodies combined with a DC-based vaccine. As a rule, cytoreduction by cyclophosphamide was required in each regimen of combination treatment, and vaccination with tumor cell-loaded DCs was more effective than vaccination with Id-keyhole limpet hemocyanin-loaded DCs. We demonstrated that under conditions of large primary tumors that had already spread to lymph nodes, when anti-CD20 antibody treatment showed minimal effect and DC vaccination had no effect, synergism between anti-CD20 antibodies and DC vaccines resulted in significant long-term survival that did not involve active antitumor antibody production. Combination treatments including tumor cell-loaded DC vaccines may therefore provide a strategy for enhancing the potency of therapy in rituximab-treated patients.

Dendritic cell-based therapeutic vaccination against myeloma: vaccine formulation determines efficacy against light chain myeloma

Multiple myeloma is an incurable plasma cell malignancy. Immunotherapy in myeloma patients had limited success to date. We have previously demonstrated that dendritic cells (DCs) pulsed with autologous Ig Id induced Id-reactive CD8(+) T cells and protection against a myeloma tumor challenge. In this work, we studied the therapeutic efficacy of chemotherapy combined with different formulations of DC-based vaccines in mice bearing large plasma cell tumors. The comparative study demonstrated that s.c. injection of DCs loaded with Id coupled to keyhole limpet hemocyanin, s.c. injection of DCs loaded with irradiated tumor cells, and intratumoral injection of naive DCs were similarly effective in mediating tumor regression and long-term survival. However, whereas the Id-keyhole limpet hemocyanin-DC vaccine was inefficient against myeloma cells that lost expression of the Ig H chain, intratumoral injection of naive DCs and s.c. injection of DCs loaded with irradiated tumor cells were highly effective against cells producing L chains only. This may be of particular importance for patients with L chain myeloma. Given that T cells respond primarily to peptides derived from H chain CDRs, attempts to treat L chain disease with myeloma protein-pulsed DCs may be futile. Vaccination with tumor cell-loaded DCs may, however, induce an effective antitumor response.

Small molecules targeting histone H4 as potential therapeutics for chronic myelogenous leukemia

We recently identified a polyamide-chlorambucil conjugate, 1R-Chl, which alkylates and down-regulates transcription of the human histone H4c gene and inhibits the growth of several cancer cell lines in vitro and in a murine SW620 xenograft model, without apparent animal toxicity. In this study, we analyzed the effects of 1R-Chl in the chronic myelogenous leukemia cell line K562 and identified another polyamide conjugate, 6R-Chl, which targets H4 genes and elicits a similar cellular response. Other polyamide conjugates that do not target the H4 gene do not elicit this response. In a murine model, both 1R-Chl and 6R-Chl were found to be highly effective in blocking K562 xenograft growth with high-dose tolerance. Unlike conventional and distamycin-based alkylators, little or no cytotoxicities and animal toxicities were observed in mg/kg dosage ranges. These results suggest that these polyamide alkylators may be a viable treatment alternative for chronic myelogenous leukemia.