RESUMO
Therapeutic vaccines that elicit cytotoxic T cell responses targeting tumor-specific neoantigens hold promise for providing long-term clinical benefit to patients with cancer. Here we evaluated safety and tolerability of a therapeutic vaccine encoding 20 shared neoantigens derived from selected common oncogenic driver mutations as primary endpoints in an ongoing phase 1/2 study in patients with advanced/metastatic solid tumors. Secondary endpoints included immunogenicity, overall response rate, progression-free survival and overall survival. Eligible patients were selected if their tumors expressed one of the human leukocyte antigen-matched tumor mutations included in the vaccine, with the majority of patients (18/19) harboring a mutation in KRAS. The vaccine regimen, consisting of a chimp adenovirus (ChAd68) and self-amplifying mRNA (samRNA) in combination with the immune checkpoint inhibitors ipilimumab and nivolumab, was shown to be well tolerated, with observed treatment-related adverse events consistent with acute inflammation expected with viral vector-based vaccines and immune checkpoint blockade, the majority grade 1/2. Two patients experienced grade 3/4 serious treatment-related adverse events that were also dose-limiting toxicities. The overall response rate was 0%, and median progression-free survival and overall survival were 1.9 months and 7.9 months, respectively. T cell responses were biased toward human leukocyte antigen-matched TP53 neoantigens encoded in the vaccine relative to KRAS neoantigens expressed by the patients' tumors, indicating a previously unknown hierarchy of neoantigen immunodominance that may impact the therapeutic efficacy of multiepitope shared neoantigen vaccines. These data led to the development of an optimized vaccine exclusively targeting KRAS-derived neoantigens that is being evaluated in a subset of patients in phase 2 of the clinical study. ClinicalTrials.gov registration: NCT03953235 .
Assuntos
Vacinas Anticâncer , Neoplasias , Vacinas , Humanos , Antígenos de Neoplasias , Vacinas Anticâncer/efeitos adversos , Antígenos HLA , Inibidores de Checkpoint Imunológico/uso terapêutico , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Proteínas Proto-Oncogênicas p21(ras)/genética , Vacinas/uso terapêuticoRESUMO
Checkpoint inhibitor (CPI) therapies provide limited benefit to patients with tumors of low immune reactivity. T cell-inducing vaccines hold promise to exert long-lasting disease control in combination with CPI therapy. Safety, tolerability and recommended phase 2 dose (RP2D) of an individualized, heterologous chimpanzee adenovirus (ChAd68) and self-amplifying mRNA (samRNA)-based neoantigen vaccine in combination with nivolumab and ipilimumab were assessed as primary endpoints in an ongoing phase 1/2 study in patients with advanced metastatic solid tumors (NCT03639714). The individualized vaccine regimen was safe and well tolerated, with no dose-limiting toxicities. Treatment-related adverse events (TRAEs) >10% included pyrexia, fatigue, musculoskeletal and injection site pain and diarrhea. Serious TRAEs included one count each of pyrexia, duodenitis, increased transaminases and hyperthyroidism. The RP2D was 1012 viral particles (VP) ChAd68 and 30 µg samRNA. Secondary endpoints included immunogenicity, feasibility of manufacturing and overall survival (OS). Vaccine manufacturing was feasible, with vaccination inducing long-lasting neoantigen-specific CD8 T cell responses. Several patients with microsatellite-stable colorectal cancer (MSS-CRC) had improved OS. Exploratory biomarker analyses showed decreased circulating tumor DNA (ctDNA) in patients with prolonged OS. Although small study size limits statistical and translational analyses, the increased OS observed in MSS-CRC warrants further exploration in larger randomized studies.
Assuntos
Neoplasias Colorretais , Pan troglodytes , Adenoviridae/genética , Animais , Neoplasias Colorretais/tratamento farmacológico , Febre , Humanos , RNA Mensageiro/uso terapêuticoRESUMO
Although CD8+ T cells are critical for controlling tumors, how they are recruited and home to primary and metastatic lesions is incompletely understood. We characterized the homing receptor (HR) ligands on tumor vasculature to determine what drives their expression and their role in T-cell entry. The anatomic location of B16-OVA tumors affected the expression of E-selectin, MadCAM-1, and VCAM-1, whereas the HR ligands CXCL9 and ICAM-1 were expressed on the vasculature regardless of location. VCAM-1 and CXCL9 expression was induced by IFNγ-secreting adaptive immune cells. VCAM-1 and CXCL9/10 enabled CD8+ T-cell effectors expressing α4ß1 integrin and CXCR3 to enter both subcutaneous and peritoneal tumors, whereas E-selectin enabled E-selectin ligand+ effectors to enter subcutaneous tumors. However, MadCAM-1 did not mediate α4ß7+ effector entry into peritoneal tumors due to an unexpected lack of luminal expression. These data establish the relative importance of certain HRs expressed on activated effectors and certain HR ligands expressed on tumor vasculature in the effective immune control of tumors. Cancer Immunol Res; 5(12); 1062-73. ©2017 AACR.
Assuntos
Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Regulação Neoplásica da Expressão Gênica , Neoplasias/etiologia , Neoplasias/patologia , Neovascularização Patológica/genética , Neovascularização Patológica/imunologia , Imunidade Adaptativa , Animais , Biomarcadores , Linhagem Celular Tumoral , Quimiocina CXCL9/genética , Selectina E/genética , Selectina E/metabolismo , Integrina alfa4beta1/genética , Ligantes , Melanoma Experimental , Camundongos , Modelos Biológicos , Receptores de Retorno de Linfócitos/metabolismo , Molécula 1 de Adesão de Célula Vascular/genéticaRESUMO
Previous work from this laboratory showed that generation of memory CD8 T cells by different immunization routes correlates with control of tumors growing in distinct sites. We hypothesized that effector CD8 T cell expression of adhesion proteins and chemokine receptors would be influenced by activation in different secondary lymphoid organs. In this report, CD8 T cells were activated by immunization with bone marrow-derived dendritic cells via i.p., i.v., or s.c. routes. Three distinct populations of activated CD8 T cells arise in mesenteric, axillary/brachial, and mediastinal lymph nodes and spleen based on differential expression of alpha4beta7 integrin, E-selectin ligand, and alpha4beta1 integrin, respectively. In contrast, three subsets of CD8 T cells defined by differential expression of P-selectin ligand and chemokine receptors were induced irrespective of activation site. The majority of activated CD8 T cells expressed CXCR3, with one subset additionally expressing P-selectin ligand, and another subset additionally expressing CCR3, CCR4, CCR5, CCR6, and CCR9. In the mesenteric lymph node, a fourth subset expressed CCR9 and CXCR3 in the absence of CCR5. Similar homing receptor profiles were induced in the same sites after localized vaccinia immunization. Homing receptor expression on CD8 T cells activated in vitro was distinct, revealing influences of both dendritic cells and the lymphoid microenvironment. Collectively, these results identify previously undescribed populations of activated CD8 T cells based on adhesion protein expression and coexpression of chemokine receptors that arise after activation in distinct secondary lymphoid organs.
Assuntos
Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Linfonodos/imunologia , Ativação Linfocitária/imunologia , Receptores de Quimiocinas/biossíntese , Baço/imunologia , Animais , Linfócitos T CD8-Positivos/patologia , Linfócitos T CD8-Positivos/virologia , Regulação da Expressão Gênica/imunologia , Inflamação/imunologia , Inflamação/metabolismo , Inflamação/virologia , Mediadores da Inflamação/metabolismo , Mediadores da Inflamação/fisiologia , Linfonodos/metabolismo , Linfonodos/patologia , Linfonodos/virologia , Ativação Linfocitária/genética , Glicoproteínas de Membrana/biossíntese , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Receptores de Quimiocinas/genética , Baço/metabolismo , Baço/patologia , Baço/virologia , Vaccinia virus/imunologiaRESUMO
Exogenous dendritic cells display restricted trafficking when injected in vivo and stimulate CD8 T cell responses that are localized to a small number of lymphoid compartments. By examining these responses in the presence and absence of FTY720, a drug that causes sequestration of T cells in lymph nodes, we demonstrate that a significant fraction of divided CD8 T cells redistribute into Ag-free lymph nodes within 3 days of activation. Despite variation in the level of expression of CD62L, redistribution of these cells is CD62L-dependent. Redistributed CD8 T cells exhibit characteristics of differentiated effectors. However, when re-isolated from Ag-free lymph nodes 3 days after activation and transferred into naive mice, they persist for at least 3 wk and expand upon Ag challenge. Thus, CD8 T cells that redistribute to Ag-free lymph nodes 3 days after immunization contain memory precursors. We suggest that this redistribution process represents an important mechanism for establishment of lymph node resident central memory, and that redistribution to Ag-free nodes is an additional characteristic to be added to those that distinguish memory precursors from terminal effectors.
Assuntos
Linfócitos T CD8-Positivos/imunologia , Memória Imunológica/imunologia , Linfonodos/imunologia , Ativação Linfocitária/imunologia , Animais , Antígenos/imunologia , Medula Óssea/imunologia , Diferenciação Celular/imunologia , Células Cultivadas , Células Dendríticas/citologia , Células Dendríticas/imunologia , Camundongos , FenótipoRESUMO
The ability of CD8+ T cells to recognize melanoma tumors has led to the development of immunotherapeutic approaches that use the antigens CD8+ T cells recognize. However, clinical response rates have been disappointing. Here we summarize our work to understand the mechanisms of self-tolerance that limit responses to currently utilized antigens and our approach to identify new antigens directly tied to malignancy. We also explore several aspects of the anti-tumor immune response induced by peptide-pulsed dendritic cells (DCs). DCs differentially augment the avidity of recall T cells specific for self-antigens and overcome a process of aberrant CD8+ T-cell differentiation that occurs in tumor-draining lymph nodes. DC migration is constrained by injection route, resulting in immune responses in localized lymphoid tissue, and differential control of tumors depending on their location in the body. We demonstrate that CD8+ T-cell differentiation in different lymphoid compartments alters the expression of homing receptor molecules and leads to the presence of systemic central memory cells. Our studies highlight several issues that must be addressed to improve the efficacy of tumor immunotherapy.
Assuntos
Antígenos de Neoplasias/imunologia , Linfócitos T CD8-Positivos/imunologia , Melanoma Experimental/imunologia , Receptores de Retorno de Linfócitos/imunologia , Tolerância a Antígenos Próprios/imunologia , Animais , Apresentação de Antígeno , Antígenos de Neoplasias/análise , Vacinas Anticâncer , Diferenciação Celular/imunologia , Apresentação Cruzada , Células Dendríticas/imunologia , Humanos , Memória Imunológica , Imunoterapia/métodos , Ativação Linfocitária , Melanoma/imunologia , Melanoma/terapia , Melanoma Experimental/terapia , Camundongos , Camundongos Transgênicos , Monofenol Mono-Oxigenase/deficiência , Monofenol Mono-Oxigenase/imunologia , Estadiamento de Neoplasias , Fosfopeptídeos/imunologia , Fosfopeptídeos/metabolismo , Receptores de Retorno de Linfócitos/biossínteseRESUMO
BACKGROUND: Marginal zone (MZ) B cells play important roles in the early phases of humoral immune responses. In addition to possessing an inherent capacity to rapidly differentiate into antibody secreting cells, MZ B cells also help to regulate the fate of both T-independent and T-dependent blood-borne antigens in the spleen. For T-dependent antigens, MZ B cells bind IgM-antigen complexes in a complement-dependent manner. Once MZ B cells bind IgM-containing immune complexes (IgM-IC), they transport them into B cell follicles for deposition onto follicular dendritic cells (FDCs), an important component of secreted IgM's ability to enhance adaptive immune responses. To further define the requirement for MZ B cells in IgM-IC deposition, mice deficient in the NF-kappaB protein p50, which have been reported to lack MZ B cells, were analyzed for their ability to trap IgM-IC onto FDCs. RESULTS: Mice (2 months of age) deficient in p50 (p50-/-) had small numbers of MZ B cells, as determined by cell surface phenotype and localization in the splenic MZ. These cells bound high levels of IgM-IC both in vivo and in vitro. Subsequent to the binding of IgM-IC by the MZ B cells in p50-/- mice, small amounts of IgM-IC were found localized on FDCs, suggesting that the MZ B cells retained their ability to transport these complexes into splenic follicles. Strikingly, MZ B cells accumulated with age in p50-/- mice. By 6 months of age, p50-/- mice contained normal numbers of these cells as defined by CD21/CD23 profile and high level expression of CD1d, CD9, and IgM, and by their positioning around the marginal sinus. However, FDCs from these older p50-/- mice exhibited a reduced capacity to trap IgM-IC and retain complement components. CONCLUSION: These results demonstrate that while the p50 component of the NF-kappaB transcription complex plays an important role in the early development of MZ B cells, MZ B cells can develop and accumulate in mice lacking this protein. These results highlight the interface between genetic deficiencies and age, and suggest that different transcription factors may play distinct roles in the development and maintenance of cell populations at different ages.
Assuntos
Envelhecimento/imunologia , Subpopulações de Linfócitos B/citologia , Células Dendríticas Foliculares/citologia , Imunoglobulina M/imunologia , Síndromes de Imunodeficiência/patologia , Subunidade p50 de NF-kappa B/fisiologia , Baço/patologia , Animais , Complexo Antígeno-Anticorpo/metabolismo , Progressão da Doença , Imunoglobulina M/administração & dosagem , Síndromes de Imunodeficiência/genética , Síndromes de Imunodeficiência/imunologia , Injeções Intravenosas , Contagem de Linfócitos , Camundongos , Camundongos Knockout , Subunidade p50 de NF-kappa B/deficiência , Subunidade p50 de NF-kappa B/genética , Baço/imunologiaRESUMO
Agents that extract or sequester membrane cholesterol stimulate IkappaB degradation and lead to NF-kappaB activation in a subset of B cells. Although the extraction of cholesterol by methyl-beta-cyclodextrin is the most potent stimulus of NF-kappaB, other agents that sequester cholesterol have similar effects. B cells and B cell lines with an immature phenotype are significantly more sensitive to the effects of cholesterol perturbation than their mature B cell counterparts. NF-kappaB activation does not involve signaling from the B cell receptor complex. Instead, the disruption of membrane cholesterol activates NF-kappaB through a MyD88-dependent pathway involving the pattern recognition receptor, Toll-like receptor 4. We suggest that lipid raft microdomains may serve not only to orchestrate receptor signaling, but to sequester signaling components one from one another, which serves to prevent receptor-mediated signaling from occurring. A role for this process during B cell development is suggested.