Antibody-mediated delivery of LIGHT to the tumor boosts natural killer cells and delays tumor progression

Targeting BTLA with the peptide inhibitor HVEM(14-39) - A new way to restore the activity of T cells in melanoma

The complex of B- and T-lymphocyte attenuator (BTLA) and herpes virus entry mediator (HVEM) plays a critical role in immune regulation and has emerged as a promising therapeutic target for cancer treatment. In this study, we investigated the potential of the peptide inhibitor HVEM(14-39) to restore peripheral T cell activity in patients with advanced melanoma. In these patients, CD8+ T cells downregulated BTLA expression and increased HVEM expression upon activation. The addition of HVEM(14-39) reduced the percentage of BTLA+ CD8+ T cells and increased the subpopulation of HVEM+ CD8+ T cells. Additionally, HVEM(14-39) enhanced T cell activation, proliferation, and the shift toward effector memory T cell subpopulations. Finally, this peptide affected the proliferation rate and late apoptosis of melanoma cell line in co-culture with T cells. These findings suggest that HVEM(14-39) can overcome T cell exhaustion and improve antitumor responses. Peptide-based immunotherapy targeting the BTLA-HVEM complex offers a promising alternative to monoclonal antibody-based therapies, with the potential for fewer side effects and higher treatment efficacy.

[Bispecific antibodies: An old story with a bright future… with CAR-T cells!]

CAR-T cells originate from two different approaches, cellular immunotherapy based on tumor immunosurveillance by T lymphocytes, combined with molecular engineering of bispecific antibodies and antibody fragments. The latter makes it possible to retarget immune effector cytotoxic cells (such as NK cells and T lymphocytes) to tumor cells through the binding to tumor-associated antigens. We present herein the history of bispecific antibodies, highlighting how such antibodies played a major role in CAR-T cell development. We will first evoke how antibody engineering led to the construction of various bispecific formats, in particular using the single chain Fv fragment (scFv) which has been used as the initial building block to generate chimeric bi-, tri- or multifunctional molecules. We will also describe how bispecific antibodies, either full IgG or as scFv or F(ab')₂ format, directed against Fcγ receptors or CD3ɛ and against tumor-associated antigens, induce a potent anti-tumor cytotoxicity following the recruitment and activation of immune effector cells, including CD3⁺ T lymphocytes. These anti-tumor effects have been translated into the clinics, especially to treat malignant hemopathies. At last, recently generated bispecific CAR-T cells suggest that the embrace between cell therapy and bispecific antibodies is not over and that we are yet to witness further discoveries enabling these cells to be even more efficient.

Cancer therapy in mice using a pure population of CD8+ T cell specific to the AH1 tumor rejection antigen

There is a growing interest in the use of patient-derived T cells for the treatment of various types of malignancies. The expansion of a polyclonal and polyspecific population of tumor-reactive T cells, with a subsequent infusion into the same donor patient, has been implemented, sometimes with positive results. It is not known, however, whether a set of T cells with a single antigen specificity may be sufficient for an effective therapy. To gain more insights in this matter, we used naturally occurring T cells recognizing a retroviral peptide (AH1), which is endogenous in many tumor cell lines of BALB/c origin and which serves as potent tumor rejection antigen. We were able to isolate and expand this rare population of T cells to numbers suitable for therapy experiments in mice (i.e., up to 30 × 10⁶ cells/mouse). After the expansion process, T cells efficiently killed antigen-positive tumor cells in vitro and demonstrated tumor growth inhibition in two syngeneic murine models of cancer. However, AH1-specific T cells failed to induce complete regressions of established tumors. The incomplete activity was associated with a failure of injected T cells to survive in vivo, as only a very limited amount of T cells was found in tumor or secondary lymphoid organs 72 h after injection. These data suggest that future therapeutic strategies based on autologous T cells may require the potentiation of tumor-homing and survival properties of cancer-specific T cells.