10 research outputs found
Cancer immunotherapy with immunomodulatory anti-CD137 and anti-PD-1 monoclonal antibodies requires Batf3-dependent dendritic cells
Weak and ineffective antitumor cytotoxic T lymphocyte (CTL) responses can be rescued by immunomodulatory mAbs targeting PD-1 or CD137. Using Batf3â/â mice, which are defective for cross-presentation of cell-associated antigens, we show that BATF3-dependent dendritic cells (DC) are essential for the response to therapy with anti-CD137 or antiâPD-1 mAbs. Batf3â/â mice failed to prime an endogenous CTL-mediated immune response toward tumor-associated antigens, including neoantigens. As a result, the immunomodulatory mAbs could not amplify any therapeutically functional immune response in these mice. Moreover, administration of systemic sFLT3L and local poly-ICLC enhanced DC-mediated cross-priming and synergized with antiâCD137- and antiâPD-1âmediated immunostimulation in tumor therapy against B16-ovalbuminâderived melanomas, whereas this function was lost in Batf3â/â mice. These experiments show that cross-priming of tumor antigens by FLT3L- and BATF3-dependent DCs is crucial to the efficacy of immunostimulatory mAbs and represents a very attractive point of intervention to enhance their clinical antitumor effects
Short-term local expression of a PD-L1 blocking antibody from a self-replicating RNA vector induces potent antitumor responses
Immune checkpoint blockade has shown anti-cancer efficacy, but requires systemic administration of monoclonal antibodies (mAbs), often leading to adverse effects. To avoid toxicity, mAbs could be expressed locally in tumors. We developed adeno-associated virus (AAV) and Semliki Forest virus (SFV) vectors expressing anti-programmed death ligand 1 (aPDL1) mAb. When injected intratumorally in MC38 tumors, both viral vectors led to similar local mAb expression at 24 h, diminishing quickly in SFV-aPDL1-treated tumors. However, SFV-aPDL1 induced >40% complete regressions and was superior to AAV-aPDL1, as well as to aPDL1 mAb given systemically or locally. SFV-aPDL1 induced abscopal effects and was also efficacious against B16-ovalbumin (OVA). The higher SFV-aPDL1 antitumor activity could be related to local upregulation of interferon-stimulated genes because of SFV RNA replication. This was confirmed by combining local SFV-LacZ administration and systemic aPDL1 mAb, which provided higher antitumor effects than each separated agent. SFVaPDL1 promoted tumor-specific CD8 T cells infiltration in both tumor models. In MC38, SFV-aPDL1 upregulated co-stimulatory markers (CD137/OX40) in tumor CD8 T cells, and its combination with anti-CD137 mAb showed more pronounced antitumor effects than each single agent. These results indicate that local transient expression of immunomodulatory mAbs using non-propagative RNA vectors inducing type I interferon (IFN-I) responses represents a potent and
Repurposing the yellow fever vaccine for intratumoral immunotherapy
Abstract Live 17D is widely used as a prophylactic vaccine strain for yellow fever virus that induces potent neutralizing humoral and cellular immunity against the wildâtype pathogen. 17D replicates and kills mouse and human tumor cell lines but not nonâtransformed human cells. Intratumoral injections with viable 17D markedly delay transplanted tumor progression in a CD8 Tâcellâdependent manner. In mice bearing bilateral tumors in which only one is intratumorally injected, contralateral therapeutic effects are observed consistent with more prominent CD8 Tâcell infiltrates and a treatmentârelated reduction of Tregs. Additive efficacy effects were observed upon coâtreatment with intratumoral 17D and systemic antiâCD137 and antiâPDâ1 immunostimulatory monoclonal antibodies. Importantly, when mice were preimmunized with 17D, intratumoral 17D treatment achieved better local and distant antitumor immunity. Such beneficial effects of prevaccination are in part explained by the potentiation of CD4 and CD8 Tâcell infiltration in the treated tumor. The repurposed use of a GMPâgrade vaccine to be given via the intratumoral route in prevaccinated patients constitutes a clinically feasible and safe immunotherapy approach
DNGR-1 limits Flt3L-mediated antitumor immunity by restraining tumor-infiltrating type I conventional dendritic cells
Background Conventional type 1 dendritic cells (cDC1s) are central to antitumor immunity and their presence in the tumor microenvironment associates with improved outcomes in patients with cancer. DNGR-1 (CLEC9A) is a dead cell-sensing receptor highly restricted to cDC1s. DNGR-1 has been involved in both cross-presentation of dead cell-associated antigens and processes of disease tolerance, but its role in antitumor immunity has not been clarified yet.Methods B16 and MC38 tumor cell lines were inoculated subcutaneously into wild-type (WT) and DNGR-1-deficient mice. To overexpress Flt3L systemically, we performed gene therapy through the hydrodynamic injection of an Flt3L-encoding plasmid. To characterize the immune response, we performed flow cytometry and RNA-Seq of tumor-infiltrating cDC1s.Results Here, we found that cross-presentation of tumor antigens in the steady state was DNGR-1-independent. However, on Flt3L systemic overexpression, tumor growth was delayed in DNGR-1-deficient mice compared with WT mice. Of note, this protection was recapitulated by anti-DNGR-1-blocking antibodies in mice following Flt3L gene therapy. This improved antitumor immunity was associated with Batf3-dependent enhanced accumulation of CD8+ T cells and cDC1s within tumors. Mechanistically, the deficiency in DNGR-1 boosted an Flt3L-induced specific inflammatory gene signature in cDC1s, including Ccl5 expression. Indeed, the increased infiltration of cDC1s within tumors and their protective effect rely on CCL5/CCR5 chemoattraction. Moreover, FLT3LG and CCL5 or CCR5 gene expression signatures correlate with an enhanced cDC1 signature and a favorable overall survival in patients with cancer. Notably, cyclophosphamide elevated serum Flt3L levels and, in combination with the absence of DNGR-1, synergized against tumor growth.Conclusion DNGR-1 limits the accumulation of tumor-infiltrating cDC1s promoted by Flt3L. Thus, DNGR-1 blockade may improve antitumor immunity in tumor therapy settings associated to high Flt3L expression
Cancer immunotherapy with immunomodulatory anti-CD137 and anti-PD-1 monoclonal antibodies requires Batf3-dependent dendritic cells
Weak and ineffective antitumor cytotoxic T lymphocyte (CTL) responses can be rescued by immunomodulatory mAbs targeting PD-1 or CD137. Using Batf3â/â mice, which are defective for cross-presentation of cell-associated antigens, we show that BATF3-dependent dendritic cells (DC) are essential for the response to therapy with anti-CD137 or antiâPD-1 mAbs. Batf3â/â mice failed to prime an endogenous CTL-mediated immune response toward tumor-associated antigens, including neoantigens. As a result, the immunomodulatory mAbs could not amplify any therapeutically functional immune response in these mice. Moreover, administration of systemic sFLT3L and local poly-ICLC enhanced DC-mediated cross-priming and synergized with antiâCD137- and antiâPD-1âmediated immunostimulation in tumor therapy against B16-ovalbuminâderived melanomas, whereas this function was lost in Batf3â/â mice. These experiments show that cross-priming of tumor antigens by FLT3L- and BATF3-dependent DCs is crucial to the efficacy of immunostimulatory mAbs and represents a very attractive point of intervention to enhance their clinical antitumor effects
Repurposing the yellow fever vaccine for intratumoral immunotherapy
Live 17D is widely used as a prophylactic vaccine strain for yellow
fever virus that induces potent neutralizing humoral and cellular
immunity against the wild-type pathogen. 17D replicates and kills
mouse and human tumor cell lines but not non-transformed
human cells. Intratumoral injections with viable 17D markedly
delay transplanted tumor progression in a CD8 T-cell-dependent
manner. In mice bearing bilateral tumors in which only one is
intratumorally injected, contralateral therapeutic effects are
observed consistent with more prominent CD8 T-cell infiltrates
and a treatment-related reduction of Tregs. Additive efficacy
effects were observed upon co-treatment with intratumoral 17D
and systemic anti-CD137 and anti-PD-1 immunostimulatory monoclonal antibodies. Importantly, when mice were preimmunized
with 17D, intratumoral 17D treatment achieved better local and
distant antitumor immunity. Such beneficial effects of prevaccination are in part explained by the potentiation of CD4 and CD8
T-cell infiltration in the treated tumor. The repurposed use of a
GMP-grade vaccine to be given via the intratumoral route in
prevaccinated patients constitutes a clinically feasible and safe
immunotherapy approach
Repurposing the yellow fever vaccine for intratumoral immunotherapy
Live 17D is widely used as a prophylactic vaccine strain for yellow
fever virus that induces potent neutralizing humoral and cellular
immunity against the wild-type pathogen. 17D replicates and kills
mouse and human tumor cell lines but not non-transformed
human cells. Intratumoral injections with viable 17D markedly
delay transplanted tumor progression in a CD8 T-cell-dependent
manner. In mice bearing bilateral tumors in which only one is
intratumorally injected, contralateral therapeutic effects are
observed consistent with more prominent CD8 T-cell infiltrates
and a treatment-related reduction of Tregs. Additive efficacy
effects were observed upon co-treatment with intratumoral 17D
and systemic anti-CD137 and anti-PD-1 immunostimulatory monoclonal antibodies. Importantly, when mice were preimmunized
with 17D, intratumoral 17D treatment achieved better local and
distant antitumor immunity. Such beneficial effects of prevaccination are in part explained by the potentiation of CD4 and CD8
T-cell infiltration in the treated tumor. The repurposed use of a
GMP-grade vaccine to be given via the intratumoral route in
prevaccinated patients constitutes a clinically feasible and safe
immunotherapy approach
Cellular cytotoxicity is a form of immunogenic cell death
Background The immune response to cancer is often
conceptualized with the cancer immunity cycle. An essential
step in this interpretation is that antigens released by dying
tumors are presented by dendritic cells to naive or memory
T cells in the tumor-draining lymph nodes. Whether tumor
cell death resulting from cytotoxicity, as mediated by T cells
or natural killer (NK) lymphocytes, is actually immunogenic
currently remains unknown.
Methods In this study, tumor cells were killed by antigenspecific T-cell receptor (TCR) transgenic CD8 T cells or
activated NK cells. Immunogenic cell death was studied
analyzing the membrane exposure of calreticulin and the
release of high mobility group box 1 (HMGB1) by the dying
tumor cells. Furthermore, the potential immunogenicity of the
tumor cell debris was evaluated in immunocompetent mice
challenged with an unrelated tumor sharing only one tumorassociated antigen and by class I major histocompatibility
complex (MHC)-multimer stainings. Mice deficient in
Batf3, Ifnar1 and Sting1 were used to study mechanistic
requirements.
Results We observe in cocultures of tumor cells and effector
cytotoxic cells, the presence of markers of immunogenic
cell death such as calreticulin exposure and soluble HMGB1
protein. Ovalbumin (OVA)-transfected MC38 colon cancer
cells, exogenously pulsed to present the gp100 epitope are
killed in culture by mouse gp100-specific TCR transgenic
CD8 T cells. Immunization of mice with the resulting
destroyed cells induces epitope spreading as observed by
detection of OVA-specific T cells by MHC multimer staining
and rejection of OVA+
EG7 lymphoma cells. Similar results
were observed in mice immunized with cell debris generated
by NK-cell mediated cytotoxicity. Mice deficient in Batf3-
dependent dendritic cells (conventional dendritic cells type 1,
cDC1) fail to develop an anti-OVA response when immunized
with tumor cells killed by cytotoxic lymphocytes. In line with
this, cultured cDC1 dendritic cells uptake and can readily
cross-present antigen from cytotoxicity-killed tumor cells to
cognate CD8+
T lymphocytes.
Conclusion These results support that an ongoing
cytotoxic antitumor immune response can lead to
immunogenic tumor cell death
Short-term local expression of a PD-L1 blocking antibody from a self-replicating RNA vector induces potent antitumor responses
Immune checkpoint blockade has shown anti-cancer efficacy, but requires systemic administration of monoclonal antibodies (mAbs), often leading to adverse effects. To avoid toxicity, mAbs could be expressed locally in tumors. We developed adeno-associated virus (AAV) and Semliki Forest virus (SFV) vectors expressing anti-programmed death ligand 1 (aPDL1) mAb. When injected intratumorally in MC38 tumors, both viral vectors led to similar local mAb expression at 24 h, diminishing quickly in SFV-aPDL1-treated tumors. However, SFV-aPDL1 induced >40% complete regressions and was superior to AAV-aPDL1, as well as to aPDL1 mAb given systemically or locally. SFV-aPDL1 induced abscopal effects and was also efficacious against B16-ovalbumin (OVA). The higher SFV-aPDL1 antitumor activity could be related to local upregulation of interferon-stimulated genes because of SFV RNA replication. This was confirmed by combining local SFV-LacZ administration and systemic aPDL1 mAb, which provided higher antitumor effects than each separated agent. SFVaPDL1 promoted tumor-specific CD8 T cells infiltration in both tumor models. In MC38, SFV-aPDL1 upregulated co-stimulatory markers (CD137/OX40) in tumor CD8 T cells, and its combination with anti-CD137 mAb showed more pronounced antitumor effects than each single agent. These results indicate that local transient expression of immunomodulatory mAbs using non-propagative RNA vectors inducing type I interferon (IFN-I) responses represents a potent and