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Blocking PD-1/PD-L1 signaling transforms cancer therapy and is assumed to unleash exhausted tumor-reactive CD8+ T cells in the tumor microenvironment (TME). However, recent studies have also indicated that the systemic tumor-reactive CD8+ T cells may respond to PD-1/PD-L1 immunotherapy. These discrepancies highlight the importance of further defining tumor-specific CD8+ T cell responders to PD-1/PD-L1 blockade. Here, using multiple preclinical tumor models, we revealed that a subset of tumor-specific CD8+ cells in the tumor draining lymph nodes (TdLNs) was not functionally exhausted but exhibited canonical memory characteristics. TdLN-derived tumor-specific memory (TTSM) cells established memory-associated epigenetic program early during tumorigenesis. More importantly, TdLN-TTSM cells exhibited superior anti-tumor therapeutic efficacy after adoptive transfer and were characterized as bona fide responders to PD-1/PD-L1 blockade. These findings highlight that TdLN-TTSM cells could be harnessed to potentiate anti-tumor immunotherapy.
Assuntos
Antígeno B7-H1 , Neoplasias , Humanos , Receptor de Morte Celular Programada 1 , Linfócitos T CD8-Positivos , Inibidores de Checkpoint Imunológico , Microambiente Tumoral , Neoplasias/terapia , Neoplasias/patologia , Linfonodos/patologiaRESUMO
Antigen-specific memory CD4+ T cells can persist and confer rapid and efficient protection from microbial reinfection. However, the mechanisms underlying the long-term maintenance of the memory CD4+ T cell pool remain largely unknown. Here, using a mouse model of acute infection with lymphocytic choriomeningitis virus (LCMV), we found that the serine/threonine kinase complex mammalian target of rapamycin complex 2 (mTORC2) is critical for the long-term persistence of virus-specific memory CD4+ T cells. The perturbation of mTORC2 signaling at memory phase led to an enormous loss of virus-specific memory CD4+ T cells by a unique form of regulated cell death (RCD), ferroptosis. Mechanistically, mTORC2 inactivation resulted in the impaired phosphorylation of downstream AKT and GSK3ß kinases, which induced aberrant mitochondrial reactive oxygen species (ROS) accumulation and ensuing ferroptosis-causative lipid peroxidation in virus-specific memory CD4+ T cells; furthermore, the disruption of this signaling cascade also inhibited glutathione peroxidase 4 (GPX4), a major scavenger of lipid peroxidation. Thus, the mTORC2-AKT-GSK3ß axis functions as a key signaling hub to promote the longevity of virus-specific memory CD4+ T cells by preventing ferroptosis.
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Linfócitos T CD4-Positivos/imunologia , Ferroptose/imunologia , Memória Imunológica/imunologia , Longevidade/imunologia , Coriomeningite Linfocítica/imunologia , Vírus da Coriomeningite Linfocítica/imunologia , Alvo Mecanístico do Complexo 2 de Rapamicina/imunologia , Animais , Glicogênio Sintase Quinase 3 beta/imunologia , Peroxidação de Lipídeos/imunologia , Ativação Linfocitária/imunologia , Contagem de Linfócitos/métodos , Camundongos Endogâmicos C57BL , Proteínas Proto-Oncogênicas c-akt/imunologiaRESUMO
Induction of the transcriptional repressor Bcl-6 in CD4(+) T cells is critical for the differentiation of follicular helper T cells (T(FH) cells), which are essential for B cell-mediated immunity. In contrast, the transcription factor Blimp1 (encoded by Prdm1) inhibits T(FH) differentiation by antagonizing Bcl-6. Here we found that the transcription factor TCF-1 was essential for both the initiation of T(FH) differentiation and the effector function of differentiated T(FH) cells during acute viral infection. Mechanistically, TCF-1 bound directly to the Bcl6 promoter and Prdm1 5' regulatory regions, which promoted Bcl-6 expression but repressed Blimp1 expression. TCF-1-null T(FH) cells upregulated genes associated with non-T(FH) cell lineages. Thus, TCF-1 functions as an important hub upstream of the Bcl-6-Blimp1 axis to initiate and secure the differentiation of T(FH) cells during acute viral infection.
Assuntos
Diferenciação Celular/imunologia , Proteínas de Ligação a DNA/imunologia , Fator 1-alfa Nuclear de Hepatócito/imunologia , Infecções por Orthomyxoviridae/imunologia , Linfócitos T Auxiliares-Indutores/imunologia , Fatores de Transcrição/imunologia , Animais , Diferenciação Celular/genética , Proteínas de Ligação a DNA/genética , Centro Germinativo/imunologia , Centro Germinativo/metabolismo , Fator 1-alfa Nuclear de Hepatócito/genética , Vírus da Influenza A , Camundongos , Camundongos Knockout , Fator 1 de Ligação ao Domínio I Regulador Positivo , Proteínas Proto-Oncogênicas c-bcl-6 , Linfócitos T Auxiliares-Indutores/metabolismo , Fatores de Transcrição/genéticaRESUMO
Follicular regulatory T (Tfr) cells differentiate from conventional regulatory T (Treg) cells and suppress excessive germinal center (GC) responses by acting on both GC B cells and T follicular helper (Tfh) cells. Here, we examined the impact of mTOR, a serine/threonine protein kinase that senses and integrates diverse environmental cues, on the differentiation and functional competency of Tfr cells in response to protein immunization or viral infection. By genetically deleting Rptor or Rictor, essential components for mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2), respectively, we found that mTORC1 but not mTORC2 is essential for Tfr differentiation. Mechanistically, mTORC1-mediated phosphorylation of the transcription factor STAT3 induced the expression of the transcription factor TCF-1 by promoting STAT3 binding to the Tcf7 5'-regulatory region. Subsequently, TCF-1 bound to the Bcl6 promoter to induce Bcl6 expression, which launched the Tfr cell differentiation program. Thus, mTORC1 initiates Tfr cell differentiation by activating the TCF-1-Bcl-6 axis during immunization or infection.
Assuntos
Imunomodulação , Complexos Multiproteicos/metabolismo , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Animais , Biomarcadores , Diferenciação Celular/imunologia , Análise por Conglomerados , Perfilação da Expressão Gênica , Fator 1-alfa Nuclear de Hepatócito/metabolismo , Imunização , Imunofenotipagem , Alvo Mecanístico do Complexo 1 de Rapamicina , Camundongos , Camundongos Transgênicos , Complexos Multiproteicos/genética , Proteínas Proto-Oncogênicas c-bcl-6/metabolismo , Fator de Transcrição STAT3/metabolismo , Transdução de Sinais , Linfócitos T Reguladores/citologia , Serina-Treonina Quinases TOR/genéticaRESUMO
BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern (VOCs), especially the Delta and Omicron variants, have been reported to show significant resistance to approved neutralizing monoclonal antibodies (mAbs) and vaccines. We previously identified a mAb named 35B5 that harbors broad neutralization to SARS-CoV-2 VOCs. Herein, we explored the protection efficacy of a 35B5-based nasal spray against SARS-CoV-2 VOCs in a small-scale clinical trial. METHODS: We enrolled 30 healthy volunteers who were nasally administered the modified 35B5 formulation. At 12, 24, 48, and 72 hours after nasal spray, the neutralization efficacy of nasal mucosal samples was assayed with pseudoviruses coated with SARS-CoV-2 spike protein of the wild-type strain or the Alpha, Beta, Delta, or Omicron variants. RESULTS: The nasal mucosal samples collected within 24 hours after nasal spray effectively neutralized SARS-CoV-2 VOCs (including Delta and Omicron). Meanwhile, the protection efficacy was 60% effective and 20% effective at 48 and 72 hours after nasal spray, respectively. CONCLUSIONS: A single nasal spray of 35B5 formation conveys 24-hour effective protection against SARS-CoV-2 VOCs, including the Alpha, Beta, Delta, or Omicron variants. Thus, 35B5 nasal spray might be potential in strengthening SARS-CoV-2 prevention, especially in high-risk populations. CLINICAL TRIALS REGISTRATION: 2022-005-02-KY.
Assuntos
COVID-19 , Humanos , Anticorpos Monoclonais/uso terapêutico , Anticorpos Neutralizantes , Anticorpos Antivirais , COVID-19/prevenção & controle , Sprays Nasais , SARS-CoV-2/genéticaRESUMO
Most cartilaginous tumors are formed during skeletal development in locations adjacent to growth plates, suggesting that they arise from disordered endochondral bone growth. Fibroblast growth factor receptor (FGFR)3 signaling plays essential roles in this process; however, the role of FGFR3 in cartilaginous tumorigenesis is not known. In this study, we found that postnatal chondrocyte-specific Fgfr3 deletion induced multiple chondroma-like lesions, including enchondromas and osteochondromas, adjacent to disordered growth plates. The lesions showed decreased extracellular signal-regulated kinase (ERK) activity and increased Indian hedgehog (IHH) expression. The same was observed in Fgfr3-deficient primary chondrocytes, in which treatment with a mitogen-activated protein kinase (MEK) inhibitor increased Ihh expression. Importantly, treatment with an inhibitor of IHH signaling reduced the occurrence of chondroma-like lesions in Fgfr3-deficient mice. This is the first study reporting that the loss of Fgfr3 function leads to the formation of chondroma-like lesions via downregulation of MEK/ERK signaling and upregulation of IHH, suggesting that FGFR3 has a tumor suppressor-like function in chondrogenesis.
Assuntos
Condroma/metabolismo , Proteínas Hedgehog/metabolismo , Receptor Tipo 3 de Fator de Crescimento de Fibroblastos/metabolismo , Regulação para Cima , Animais , Linhagem Celular , Células Cultivadas , Condrócitos/metabolismo , Condroma/genética , Proteínas Hedgehog/genética , Sistema de Sinalização das MAP Quinases , Camundongos , Camundongos Endogâmicos C57BL , Receptor Tipo 3 de Fator de Crescimento de Fibroblastos/deficiência , Receptor Tipo 3 de Fator de Crescimento de Fibroblastos/genéticaRESUMO
The mammalian target of rapamycin (mTOR) is a serine-threonine kinase that has been shown to be essential for the differentiation and function of various immune cells. Earlier in vitro studies showed that mTOR signalling regulates B-cell biology by supporting their activation and proliferation. However, how mTOR signalling temporally regulates in vivo germinal centre B (GCB) cell development and differentiation into short-lived plasma cells, long-lived plasma cells and memory cells is still not well understood. In this study, we used a combined conditional/inducible knock-out system to investigate the temporal regulation of mTOR complex 1 (mTORC1) in the GCB cell response to acute lymphocytic choriomeningitis virus infection by deleting Raptor, a main component of mTORC1, specifically in B cells in pre- and late GC phase. Early Raptor deficiency strongly inhibited GCB cell proliferation and differentiation and plasma cell differentiation. Nevertheless, late GC Raptor deficiency caused only decreases in the size of memory B cells and long-lived plasma cells through poor maintenance of GCB cells, but it did not change their differentiation. Collectively, our data revealed that mTORC1 signalling supports GCB cell responses at both early and late GC phases during viral infection but does not regulate GCB cell differentiation into memory B cells and plasma cells at the late GC stage.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Linfócitos B/enzimologia , Centro Germinativo/enzimologia , Coriomeningite Linfocítica/enzimologia , Vírus da Coriomeningite Linfocítica/imunologia , Complexos Multiproteicos/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/deficiência , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/imunologia , Animais , Linfócitos B/imunologia , Linfócitos B/transplante , Linfócitos B/virologia , Transplante de Medula Óssea , Diferenciação Celular , Proliferação de Células , Modelos Animais de Doenças , Predisposição Genética para Doença , Centro Germinativo/imunologia , Centro Germinativo/virologia , Interações Hospedeiro-Patógeno , Imunidade Humoral , Memória Imunológica , Ativação Linfocitária , Coriomeningite Linfocítica/genética , Coriomeningite Linfocítica/imunologia , Coriomeningite Linfocítica/virologia , Vírus da Coriomeningite Linfocítica/patogenicidade , Alvo Mecanístico do Complexo 1 de Rapamicina , Camundongos Endogâmicos C57BL , Camundongos Knockout , Complexos Multiproteicos/deficiência , Complexos Multiproteicos/genética , Complexos Multiproteicos/imunologia , Fenótipo , Plasmócitos/enzimologia , Plasmócitos/imunologia , Plasmócitos/virologia , Proteína Regulatória Associada a mTOR , Transdução de Sinais , Serina-Treonina Quinases TOR/deficiência , Serina-Treonina Quinases TOR/genética , Serina-Treonina Quinases TOR/imunologia , Fatores de Tempo , Quimeras de TransplanteRESUMO
Tumor antigen-specific CD8+ T cells from draining lymph nodes gain an accumulating importance in mounting anti-tumor immune response during tumorigenesis. However, in many cases, cancer cells form metastatic loci in lymph nodes before further metastasizing to distant organs. To what extent the local and systematic CD8+ T cell responses were influenced by LN metastasis remains obscure. To this end, we set up a murine LN metastasis model combined with a B16F10-GP melanoma cell line expressing the surrogate neoantigen derived from lymphocytic choriomeningitis virus (LCMV), glycoprotein (GP), and P14 transgenic mice harboring T cell receptors (TCRs) specific to GP-derived peptide GP33-41 presented by the class I major histocompatibility complex (MHC) molecule H-2Db. This protocol enables the study of antigen-specific CD8+ T cell responses during LN metastasis. In this protocol, C57BL/6J mice were subcutaneously implanted with B16F10-GP cells, followed by adoptive transfer with naive P14 cells. When the subcutaneous tumor grew to approximately 5 mm in diameter, the primary tumor was excised, and B16F10-GP cells were directly injected into the tumor draining lymph node (TdLN). Then, the dynamics of CD8+ T cells were monitored during the process of LN metastasis. Collectively, this model has provided an approach to precisely investigate the antigen-specific CD8+ T cell immune responses during LN metastasis.
Assuntos
Antígenos , Linfócitos T CD8-Positivos , Camundongos , Animais , Metástase Linfática , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Antígenos/metabolismo , Vírus da Coriomeningite Linfocítica , Glicoproteínas/metabolismo , Carcinogênese/metabolismo , LinfonodosRESUMO
Tumor-specific T cells are crucial in anti-tumor immunity and act as targets for cancer immunotherapies. However, these cells are numerically scarce and functionally exhausted in the tumor microenvironment (TME), leading to inefficacious immunotherapies in most patients with cancer. By contrast, emerging evidence suggested that tumor-irrelevant bystander T (TBYS) cells are abundant and preserve functional memory properties in the TME. To leverage TBYS cells in the TME to eliminate tumor cells, we engineered oncolytic virus (OV) encoding TBYS epitopes (OV-BYTE) to redirect the antigen specificity of tumor cells to pre-existing TBYS cells, leading to effective tumor inhibition in multiple preclinical models. Mechanistically, OV-BYTE induced epitope spreading of tumor antigens to elicit more diverse tumor-specific T cell responses. Remarkably, the OV-BYTE strategy targeting human severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific T cell memory efficiently inhibited tumor progression in a human tumor cell-derived xenograft model, providing important insights into the improvement of cancer immunotherapies in a large population with a history of SARS-CoV-2 infection or coronavirus disease 2019 (COVID-19) vaccination.
Assuntos
Epitopos de Linfócito T , Imunoterapia , Neoplasias , Vírus Oncolíticos , SARS-CoV-2 , Microambiente Tumoral , Humanos , Animais , Camundongos , Vírus Oncolíticos/imunologia , Imunoterapia/métodos , Epitopos de Linfócito T/imunologia , Microambiente Tumoral/imunologia , SARS-CoV-2/imunologia , Neoplasias/terapia , Neoplasias/imunologia , Terapia Viral Oncolítica/métodos , Linhagem Celular Tumoral , COVID-19/imunologia , COVID-19/terapia , Ensaios Antitumorais Modelo de Xenoenxerto , Feminino , Antígenos de Neoplasias/imunologia , Linfócitos T/imunologiaRESUMO
Reversible chemical delithiation/lithiation of LiFePO(4) was successfully demonstrated using ferrocene derivatives, based on which a novel energy storage system--the redox flow lithium-ion battery (RFLB), was devised by integrating the operation flexibility of a redox flow battery and high energy density of a lithium-ion battery. Distinct from the recent semi-solid lithium rechargeable flow battery, the energy storage materials of RFLB stored in separate energy tanks remain stationary upon operation, giving us a fresh perspective on building large-scale energy storage systems with higher energy density and improved safety.
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Human monkeypox is a viral zoonotic smallpox-like disease caused by the monkeypox virus (MPXV) and has become the greatest public health threat in the genus Orthopoxvirus after smallpox was eradicated. The host immune response to MPXV plays an essential role in disease pathogenesis and clinical manifestations. MPXV infection leads to skin lesions with the genital area as the main feature in the current outbreak and triggers a strong immune response that results in sepsis, deep tissue abscess, severe respiratory disease, and injuries to multiple immune organs. Emerging evidence shows that the immunopathogenesis of MPXV infection is closely associated with impaired NK-cell function, lymphopenia, immune evasion, increased antibodies, increased blood monocytes and granulocytes, cytokine storm, inhibition of the host complement system, and antibody-dependent enhancement. In this overview, we discuss the immunopathology and immunopathogenesis of monkeypox to aid the development of novel immunotherapeutic strategies against monkeypox.
Assuntos
Mpox , Varíola , Humanos , Monkeypox virus/fisiologia , Mpox/epidemiologia , Mpox/patologia , ImunidadeRESUMO
The COVID-19 vaccinations are crucial in protecting against the global pandemic. However, accumulating studies revealed the severely blunted COVID-19 vaccine effectiveness in cancer patients. The PD-1/PD-L1 immune checkpoint blockade (ICB) therapy leads to durable therapeutic responses in a subset of cancer patients and has been approved to treat a wide spectrum of cancers in the clinic. In this regard, it is pivotal to explore the potential impact of PD-1/PD-L1 ICB therapy on COVID-19 vaccine effectiveness during ongoing malignancy. In this study, using preclinical models, we found that the tumor-suppressed COVID-19 vaccine responses are largely reverted in the setting of PD-1/PD-L1 ICB therapy. We also identified that the PD-1/PD-L1 blockade-directed restoration of COVID-19 vaccine effectiveness is irrelevant to anti-tumor therapeutic outcomes. Mechanistically, the restored COVID-19 vaccine effectiveness is entwined with the PD-1/PD-L1 blockade-driven preponderance of follicular helper T cell and germinal center responses during ongoing malignancy. Thus, our findings indicate that PD-1/PD-L1 blockade will greatly normalize the responses of cancer patients to COVID-19 vaccination, while regardless of its anti-tumor efficacies on these patients.
Assuntos
COVID-19 , Neoplasias , Humanos , Vacinas contra COVID-19 , Inibidores de Checkpoint Imunológico/uso terapêutico , Antígeno B7-H1 , Receptor de Morte Celular Programada 1 , COVID-19/prevenção & controle , Neoplasias/terapia , ImunoterapiaRESUMO
Follicular regulatory T cells (Tfrs), a specialized subset of regulatory T cells (Tregs), have a particular role in the control of follicular helper T cell-driven germinal center (GC) responses. Following differentiation signals similar to those received by follicular helper T cells (Tfhs), Tfrs gain expression of characteristic chemokine receptors and transcription factors, such as CXCR5 and Bcl-6, allowing them to migrate into the B-cell follicle and perform in situ suppression. Thus, together with Tfhs, Tfrs help maintaining an optimized GC-reaction. However, the mechanism underlying the Treg-to-Tfr transition remains obscure. Here, we established a highly reproducible protocol for investigating the differentiation of Tregs into Tfrs by constructing spleen-chimeric mice combined with retrovirus transduction. We demonstrated that using this strategy, over 4 folds of Tregs could differentiate into Tfrs in Bcl-6 overexpression group compared to control counterparts (Migr1), and Bcl-6 could efficiently promote Tfr differentiation during acute viral infection. Hence, this method provides us an easy access to investigate the factors that regulate the differentiation program that converts Tregs into Tfrs, which will enhance our understanding of the networks regulating GC-reaction and shed new light on the molecular basis of immune homeostasis.
Assuntos
Linfócitos T Reguladores , Viroses , Animais , Linfócitos B , Centro Germinativo , Camundongos , Receptores CXCR5/metabolismo , Linfócitos T Auxiliares-Indutores , Viroses/metabolismoRESUMO
Cytotoxic CD8+ T cells are the main focus of efforts to understand anti-tumor immunity and immunotherapy. The adoptive transfer of tumor-reactive cytotoxic CD8+ T lymphocytes expanded and differentiated in vitro has long been considered the primary strategy in adaptive anti-tumor immunity, however, the majority of the transferred tumor antigen-specific CD8+ T cells differentiated into CD39+CD69+ exhausted progenies, limiting its effects in repressing tumor growth. Contrarily, less attention has been addressed to the role of CD4+ T cells during tumorigenesis. Using a mouse model of metastatic melanoma, we found that transferring tumor-specific CD4+ T cells into recipients induces substantial regression of the established metastatic tumors. Notably, in vitro activated CD4+ T cells developed into cytotoxic CD4- T cells in vivo and get exhausted gradually. The blockade of PD-L1 signaling resulted in an expansion of tumor specific CD4+ T cells, which could better control the established metastatic melanoma. Moreover, the tumor-specific memory CD4+ T cell can prevent mice from tumor metastasis, and the tumor-specific effector CD4+ T cells can also mitigate the established metastatic tumor. Overall, our findings suggest a novel mechanism of CD4+ T cells in curtailing tumor metastasis and confirm their therapeutic role in combination with PD-L1 blockade in cancer immunotherapy. Hence, a better understanding of cytotoxic CD4- T cell-mediated tumor regression could provide an alternative choice for patients exhibiting suboptimal or no response to CD8+ T cell-based immunotherapies.
Assuntos
Antineoplásicos , Melanoma , Segunda Neoplasia Primária , Antígeno B7-H1 , Linfócitos T CD4-Positivos , Linfócitos T CD8-Positivos , HumanosRESUMO
Exhausted CD8+ T (Tex) cells are caused by persistent antigenic stimulation during chronic viral infection or tumorigenesis. Tex cells upregulate and sustain the expressions of multiple immune inhibitory receptors (IRs). Blocking IRs of Tex cells, exemplified by PD-1, can partially restore their effector functions and thus lead to viral suppression or tumor remission. Tex cells derived from chronic viral infections share the expression spectrum of IRs with Tex cells derived from tumors; however, whether any IRs are selectively expressed by tumor-derived Tex cells or virus-derived Tex cells remains to be learnt. In the study, we found that Tex cells upregulate IR natural killer cell lectin-like receptor isoform A (NKG2A) specifically in the context of tumor but not chronic viral infection. Moreover, the NKG2A expression is attributed to tumor antigen recognition and thus bias expressed by tumor-specific Tex cells in the tumor microenvironment instead of their counterparts in the periphery. Such dichotomous NKG2A expression further dictates the differential responsiveness of Tex cells to NKG2A immune checkpoint blockade. Therefore, our study highlighted NKG2A as a disease-dependent IR and provided novel insights into the distinct regulatory mechanisms underlying T cell exhaustion between tumor and chronic viral infection.
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BACKGROUND: Antitumor therapeutic vaccines are generally based on antigenic epitopes presented by major histocompatibility complex (MHC-I) molecules to induce tumor-specific CD8+ T cells. Paradoxically, continuous T cell receptor (TCR) stimulation from tumor-derived CD8+ T-cell epitopes can drive the functional exhaustion of tumor-specific CD8+ T cells. Tumor-specific type-I helper CD4+ T (TH1) cells play an important role in the population maintenance and cytotoxic function of exhausted tumor-specific CD8+ T cells in the tumor microenvironment. Nonetheless, whether the vaccination strategy targeting MHC-II-restricted CD4+ T-cell epitopes to induce tumor-specific TH1 responses can confer effective antitumor immunity to restrain tumor growth is not well studied. Here, we developed a heterologous prime-boost vaccination strategy to effectively induce tumor-specific TH1 cells and evaluated its antitumor efficacy and its capacity to potentiate PD-1/PD-L1 immunotherapy. METHODS: Listeria monocytogenes vector and influenza A virus (PR8 strain) vector stably expressing lymphocytic choriomeningitis virus (LCMV) glycoprotein-specific I-Ab-restricted CD4+ T cell epitope (GP61-80) or ovalbumin-specific CD4+ T cell epitope (OVA323-339) were constructed and evaluated their efficacy against mouse models of melanoma and colorectal adenocarcinoma expressing lymphocytic choriomeningitis virus glycoprotein and ovalbumin. The impact of CD4+ T cell epitope-based heterologous prime-boost vaccination was detected by flow-cytometer, single-cell RNA sequencing and single-cell TCR sequencing. RESULTS: CD4+ T cell epitope-based heterologous prime-boost vaccination efficiently suppressed both mouse melanoma and colorectal adenocarcinoma. This vaccination primarily induced tumor-specific TH1 response, which in turn enhanced the expansion, effector function and clonal breadth of tumor-specific CD8+ T cells. Furthermore, this vaccination strategy synergized PD-L1 blockade mediated tumor suppression. Notably, prime-boost vaccination extended the duration of PD-L1 blockade induced antitumor effects by preventing the re-exhaustion of tumor-specific CD8+ T cells. CONCLUSION: CD4+ T cell epitope-based heterologous prime-boost vaccination elicited potent both tumor-specific TH1 and CTL response, leading to the efficient tumor control. This strategy can also potentiate PD-1/PD-L1 immune checkpoint blockade (ICB) against cancer.
Assuntos
Adenocarcinoma , Neoplasias Colorretais , Melanoma , Animais , Antígeno B7-H1/farmacologia , Linfócitos T CD4-Positivos , Linfócitos T CD8-Positivos , Epitopos de Linfócito T , Glicoproteínas , Humanos , Inibidores de Checkpoint Imunológico , Imunoterapia , Camundongos , Ovalbumina , Receptor de Morte Celular Programada 1 , Receptores de Antígenos de Linfócitos T , Microambiente Tumoral , VacinaçãoRESUMO
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a global pandemic of novel coronavirus disease (COVID-19). The neutralizing monoclonal antibodies (mAbs) targeting the receptor-binding domain (RBD) of SARS-CoV-2 are among the most promising strategies to prevent and treat COVID-19. However, SARS-CoV-2 variants of concern (VOCs) profoundly reduced the efficacies of most of mAbs and vaccines approved for clinical use. Herein, we demonstrated mAb 35B5 efficiently neutralizes both wild-type (WT) SARS-CoV-2 and VOCs, including B.1.617.2 (delta) variant, in vitro and in vivo. Cryo-electron microscopy (cryo-EM) revealed that 35B5 neutralizes SARS-CoV-2 by targeting a unique epitope that avoids the prevailing mutation sites on RBD identified in circulating VOCs, providing the molecular basis for its pan-neutralizing efficacy. The 35B5-binding epitope could also be exploited for the rational design of a universal SARS-CoV-2 vaccine.
Assuntos
Anticorpos Monoclonais , Anticorpos Antivirais , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus , Anticorpos Monoclonais/química , Anticorpos Antivirais/química , COVID-19 , Microscopia Crioeletrônica , Humanos , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/imunologiaRESUMO
The adaptive immunity that protects patients from coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is not well characterized. In particular, the asymptomatic patients have been found to induce weak and transient SARS-CoV-2 antibody responses, but the underlying mechanisms remain unknown; meanwhile, the protective immunity that guide the recovery of these asymptomatic patients is elusive. Here, we characterized SARS-CoV-2-specific B-cell and T-cell responses in 10 asymptomatic patients and 64 patients with other disease severity (mild, n = 10, moderate, n = 32, severe, n = 12) and found that asymptomatic or mild symptomatic patients failed to mount virus-specific germinal center (GC) B cell responses that result in robust and prolonged humoral immunity, assessed by GC response indicators including follicular helper T (TFH) cell and memory B cell responses as well as serum CXCL13 levels. Alternatively, these patients mounted potent virus-specific TH1 and CD8+ T cell responses. In sharp contrast, patients of moderate or severe disease induced vigorous virus-specific GC B cell responses and associated TFH responses; however, the virus-specific TH1 and CD8+ T cells were minimally induced in these patients. These results, therefore, uncovered the protective immunity in asymptomatic patients and also revealed the strikingly dichotomous and incomplete humoral and cellular immune responses in COVID-19 patients with different disease severity, providing important insights into rational design of effective COVID-19 vaccines.
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Imunidade Adaptativa , Linfócitos B/imunologia , Linfócitos T CD8-Positivos/imunologia , COVID-19/imunologia , SARS-CoV-2/imunologia , Células Th1/imunologia , Adulto , Linfócitos B/patologia , Linfócitos T CD8-Positivos/patologia , COVID-19/patologia , Feminino , Humanos , Masculino , Índice de Gravidade de Doença , Células Th1/patologiaRESUMO
T cell-mediated immunity plays a crucial role in immune responses against tumors, with cytotoxic T lymphocytes (CTLs) playing the leading role in eradicating cancerous cells. However, the origins and replenishment of tumor antigen-specific CD8+ T cells within the tumor microenvironment (TME) remain obscure. This protocol employs the B16F10-OVA melanoma cell line, which stably expresses the surrogate neoantigen, ovalbumin (OVA), and TCR transgenic OT-I mice, in which over 90% of CD8+ T cells specifically recognize the OVA-derived peptide OVA257-264 (SIINFEKL) bound to the class I major histocompatibility complex (MHC) molecule H2-Kb. These features enable the study of antigen-specific T cell responses during tumorigenesis. Combining this model with tumor transplantation surgery, tumor tissues from donors were transplanted into tumor-matched syngeneic recipient mice to precisely trace the influx of recipient-derived immune cells into transplanted donor tissues, allowing the analysis of the immune responses of tumor-inherent and periphery-originated antigen-specific CD8+ T cells. A dynamic transition was found to occur between these two populations. Collectively, this experimental design has provided another approach to precisely investigate the immune responses of CD8+ T cells in TME, which will shed new light on tumor immunology.
Assuntos
Linfócitos T CD8-Positivos , Neoplasias , Animais , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Ovalbumina , Linfócitos T Citotóxicos , Microambiente TumoralRESUMO
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a global pandemic of novel coronavirus disease (COVID-19). Though vaccines and neutralizing monoclonal antibodies (mAbs) have been developed to fight COVID-19 in the past year, one major concern is the emergence of SARS-CoV-2 variants of concern (VOCs). Indeed, SARS-CoV-2 VOCs such as B.1.1.7 (UK), B.1.351 (South Africa), P.1 (Brazil), and B.1.617.1 (India) now dominate the pandemic. Herein, we found that binding activity and neutralizing capacity of sera collected from convalescent patients in early 2020 for SARS-CoV-2 VOCs, but not non-VOC variants, were severely blunted. Furthermore, we observed evasion of SARS-CoV-2 VOCs from a VH3-30 mAb 32D4, which was proved to exhibit highly potential neutralization against wild-type (WT) SARS-CoV-2. Thus, these results indicated that SARS-CoV-2 VOCs might be able to spread in convalescent patients and even harbor resistance to medical countermeasures. New interventions against these SARS-CoV-2 VOCs are urgently needed.