技术资料

Killer cell lectin-like receptor F1 (KLRF1) is an activating C-type lectin-like receptor expressed on human NK cells and subsets of T cells. In this study,we show that activation-induced C-type lectin (AICL) is a unique KLRF1 ligand expressed on tumor cell lines of hematopoietic and non-hematopoietic origins. We screened a panel of human tumor cell lines using the KLRF1 reporter cells and found that several tumor lines expressed KLRF1 ligands. We characterized a putative KLRF1 ligand expressed on the U937 cell line. The molecular mass for the deglycosylated ligand was 28 kDa under non-reducing condition and 17 kDa under reducing condition,suggesting that the KLRF1 ligand is a homodimer. By expression cloning from a U937 cDNA library,we identified AICL as a KLRF1 ligand. We generated mAbs against AICL to identify the KLRF1 ligands on non-hematopoietic tumor lines. The anti-AICL mAbs stained the tumor lines that express the KLRF1 ligands and importantly the interaction of KLRF1 with the KLRF1 ligand on non-hematopoietic tumors was completely blocked by the two anti-AICL mAbs. Moreover,NK cell degranulation triggered by AICL-expressing targets was partially inhibited by the anti-AICL mAb. Finally,we demonstrate that AICL is expressed in human primary liver cancers. These results suggest that AICL is expressed on tumor cells of non-hematopoietic origins and raise the possibility that AICL may contribute to NK cell surveillance of tumor cells. View Publication

Two critical concerns in clinical cord blood transplantation are the initial time to engraftment and the subsequent restoration of immune function. These studies measured the impact of progenitor cell dose on both the pace and strength of hematopoietic reconstitution by transplanting nonobese diabetic/severe combined immunodeficiency/interleukin-2 receptor-gamma-null (NSγ) mice with lineage-depleted aldehyde dehydrogenase-bright CD34(+) human cord blood progenitors. The progress of each transplant was monitored over an extended time course by repeatedly analyzing the peripheral blood for human hematopoietic cells. In vivo human hematopoietic development was complete. After long-term transplantation assays (≥ 19 weeks),human T-cell development was documented within multiple tissues in 16 of 32 NSγ mice. Human T-cell differentiation was active within NSγ thymuses,as documented by the presence of CD4(+) CD8(+) T-cell progenitors as well as T-cell receptor excision circles. It is important to note that although myeloid and B-cell engraftment was detected as early as 4 weeks after transplantation,human T-cell development was exclusively late onset. High progenitor cell doses were associated with a robust human hematopoietic chimerism that accelerated both initial time to engraftment and subsequent T-cell development. At lower progenitor cell doses,the chimerism was weak and the human hematopoietic lineage development was frequently incomplete. View Publication

Improving effector T-cell functions is highly desirable for preventive or therapeutic interventions of diverse diseases. Signal transducer and activator of transcription 3 (Stat3) in the myeloid compartment constrains Th1-type immunity,dampening natural and induced antitumor immune responses. We have recently developed an in vivo small interfering RNA (siRNA) delivery platform by conjugating a Toll-like receptor 9 agonist with siRNA that efficiently targets myeloid and B cells. Here,we show that either CpG triggering combined with the genetic Stat3 ablation in myeloid/B cell compartments or administration of the CpG-Stat3siRNA drastically augments effector functions of adoptively transferred CD8+ T cells. Specifically,we show that both approaches are capable of increasing dendritic cell and CD8(+) T-cell engagement in tumor-draining lymph nodes. Furthermore,both approaches can significantly activate the transferred CD8(+) T cells in vivo,upregulating effector molecules such as perforin,granzyme B,and IFN-γ. Intravital multiphoton microscopy reveals that Stat3 silencing combined with CpG triggering greatly increases killing activity and tumor infiltration of transferred T cells. These results suggest the use of CpG-Stat3siRNA,and possibly other Stat3 inhibitors,as a potent adjuvant to improve T-cell therapies. View Publication

Immunostimulatory agents such as agonistic anti-CD137 and interleukin (IL)-2 generate effective anti-tumor immunity but also elicit serious toxicities,hampering their clinical application. Here we show that combination therapy with anti-CD137 and an IL-2-Fc fusion achieves significant initial anti-tumor activity,but also lethal immunotoxicity deriving from stimulation of circulating leukocytes. To overcome this toxicity,we demonstrate that anchoring IL-2 and anti-CD137 on the surface of liposomes allows these immune agonists to rapidly accumulate in tumors while lowering systemic exposure. In multiple tumor models,immunoliposome delivery achieves anti-tumor activity equivalent to free IL-2/anti-CD137 but with the complete absence of systemic toxicity. Immunoliposomes stimulated tumor infiltration by cytotoxic lymphocytes,cytokine production,and granzyme expression,demonstrating equivalent immunostimulatory effects to the free drugs in the local tumor microenvironment. Thus,surface-anchored particle delivery may provide a general approach to exploit the potent stimulatory activity of immune agonists without debilitating systemic toxicities. View Publication

During adaptive immune responses,CD8(+) T cells with low TCR affinities are released early into the circulation before high-affinity clones become dominant at later time points. How functional avidity maturation is orchestrated in lymphoid tissue and how low-affinity cells contribute to host protection remains unclear. In this study,we used intravital imaging of reactive lymph nodes (LNs) to show that T cells rapidly attached to dendritic cells irrespective of TCR affinity,whereas one day later,the duration of these stable interactions ceased progressively with lowering peptide major histocompatibility complex (pMHC) affinity. This correlated inversely BATF (basic leucine zipper transcription factor,ATF-like) and IRF4 (interferon-regulated factor 4) induction and timing of effector differentiation,as low affinity-primed T cells acquired cytotoxic activity earlier than high affinity-primed ones. After activation,low-affinity effector CD8(+) T cells accumulated at efferent lymphatic vessels for egress,whereas high affinity-stimulated CD8(+) T cells moved to interfollicular regions in a CXCR3-dependent manner for sustained pMHC stimulation and prolonged expansion. The early release of low-affinity effector T cells led to rapid target cell elimination outside reactive LNs. Our data provide a model for affinity-dependent spatiotemporal orchestration of CD8(+) T cell activation inside LNs leading to functional avidity maturation and uncover a role for low-affinity effector T cells during early microbial containment. View Publication

Spatial organization of the genome plays a central role in gene expression,DNA replication,and repair. But current epigenomic approaches largely map DNA regulatory elements outside of the native context of the nucleus. Here we report assay of transposase-accessible chromatin with visualization (ATAC-see),a transposase-mediated imaging technology that employs direct imaging of the accessible genome in situ,cell sorting,and deep sequencing to reveal the identity of the imaged elements. ATAC-see revealed the cell-type-specific spatial organization of the accessible genome and the coordinated process of neutrophil chromatin extrusion,termed NETosis. Integration of ATAC-see with flow cytometry enables automated quantitation and prospective cell isolation as a function of chromatin accessibility,and it reveals a cell-cycle dependence of chromatin accessibility that is especially dynamic in G1 phase. The integration of imaging and epigenomics provides a general and scalable approach for deciphering the spatiotemporal architecture of gene control. View Publication

In several clinical contexts,the measurement of ATP concentration in T lymphocytes has been proposed as a biomarker of immune status,predictive of secondary infections. However,the use of such biomarker in lymphopenic patients requires some adaptations in the ATP dosage protocol. We used blood from healthy volunteers to determine the optimal experimental settings. We investigated technical aspects such as the type of anticoagulant for blood sampling,the effect of freeze and thaw cycles,the reagent and sample mixing sequence,and the optimal dilution buffer. We also shortened the incubation time to 8h,and even showed that a 30min incubation may be sufficient. To evaluate the ATP rise upon lymphocyte activation,the optimal dose of stimulant was defined to be 4μg/mL of phytohaemagglutinin. Lastly,we determined that the number of T cells needed for this measurement was as low as 50,000,which is compatible with the existing lymphopenia in clinical settings. This optimized protocol appears ready to be assessed in lymphopenic patients to further investigate the interconnection between T lymphocyte metabolism and impaired phenotype and functions. View Publication

Redirecting T cells to attack cancer using engineered chimeric receptors provides powerful new therapeutic capabilities. However,the effectiveness of therapeutic T cells is constrained by the endogenous T cell response: certain facets of natural response programs can be toxic,whereas other responses,such as the ability to overcome tumor immunosuppression,are absent. Thus,the efficacy and safety of therapeutic cells could be improved if we could custom sculpt immune cell responses. Synthetic Notch (synNotch) receptors induce transcriptional activation in response to recognition of user-specified antigens. We show that synNotch receptors can be used to sculpt custom response programs in primary T cells: they can drive a la carte cytokine secretion profiles,biased T cell differentiation,and local delivery of non-native therapeutic payloads,such as antibodies,in response to antigen. SynNotch T cells can thus be used as a general platform to recognize and remodel local microenvironments associated with diverse diseases. View Publication

Regions of the normal arterial intima predisposed to atherosclerosis are sites of ongoing monocyte trafficking and also contain resident myeloid cells with features of dendritic cells. However,the pathophysiological roles of these cells are poorly understood. Here we found that intimal myeloid cells underwent reverse transendothelial migration (RTM) into the arterial circulation after systemic stimulation of pattern-recognition receptors (PRRs). This process was dependent on expression of the chemokine receptor CCR7 and its ligand CCL19 by intimal myeloid cells. In mice infected with the intracellular pathogen Chlamydia muridarum,blood monocytes disseminated infection to the intima. Subsequent CCL19-CCR7-dependent RTM was critical for the clearance of intimal C. muridarum. This process was inhibited by hypercholesterolemia. Thus,RTM protects the normal arterial intima,and compromised RTM during atherogenesis might contribute to the intracellular retention of pathogens in atherosclerotic lesions. View Publication

The T-cell surface molecule TIGIT is an immune checkpoint molecule that inhibits T-cell responses,but its roles in cancer are little understood. In this study,we evaluated the role TIGIT checkpoint plays in the development and progression of gastric cancer. We show that the percentage of CD8 T cells that are TIGIT+ was increased in gastric cancer patients compared with healthy individuals. These cells showed functional exhaustion with impaired activation,proliferation,cytokine production,and metabolism,all of which were rescued by glucose. In addition,gastric cancer tissue and cell lines expressed CD155,which bound TIGIT receptors and inactivated CD8 T cells. In a T cell-gastric cancer cell coculture system,gastric cancer cells deprived CD8 T cells of glucose and impaired CD8 T-cell effector functions; these effects were neutralized by the additional glucose or by TIGIT blockade. In gastric cancer tumor cells,CD155 silencing increased T-cell metabolism and IFNγ production,whereas CD155 overexpression inhibited T-cell metabolism and IFNγ production; this inhibition was neutralized by TIGIT blockade. Targeting CD155/TIGIT enhanced CD8 T-cell reaction and improved survival in tumor-bearing mice. Combined targeting of TIGIT and PD-1 further enhanced CD8 T-cell activation and improved survival in tumor-bearing mice. Our results suggest that gastric cancer cells inhibit CD8 T-cell metabolism through CD155/TIGIT signaling,which inhibits CD8 T-cell effector functions,resulting in hyporesponsive antitumor immunity. These findings support the candidacy of CD155/TIGIT as a potential therapeutic target in gastric cancer. Cancer Res; 77(22); 6375-88. textcopyright2017 AACR. View Publication

Current antiretroviral therapy (ART) for HIV/AIDS slows disease progression by reducing viral loads and increasing CD4 counts. Yet ART is not curative due to the persistence of CD4+ T-cell proviral reservoirs that chronically resupply active virus. Elimination of these reservoirs through the administration of synergistic combinations of latency reversing agents (LRAs),such as histone deacetylase (HDAC) inhibitors and protein kinase C (PKC) modulators,provides a promising strategy to reduce if not eradicate the viral reservoir. Here,we demonstrate that largazole and its analogues are isoform-targeted histone deacetylase inhibitors and potent LRAs. Significantly,these isoform-targeted HDAC inhibitors synergize with PKC modulators,namely bryostatin-1 analogues (bryologs). Implementation of this unprecedented LRA combination induces HIV-1 reactivation to unparalleled levels and avoids global T-cell activation within resting CD4+ T-cells. View Publication

Natural T regulatory cells (nTregs) play a key role in inducing and maintaining immunological tolerance. Cell-based therapy using purified nTregs is under consideration for several conditions,but procedures employed to date have resulted in cell populations that are contaminated with cytokine secreting effector cells. We have established a method for isolation and ex vivo expansion of human nTregs from healthy blood donors for cellular therapy aimed at preventing allograft rejection in organ transplants. The Robosep instrument was used for initial nTreg isolation and rapamycin was included in the expansion phase of cell cultures. The resulting cell population exhibited a stable CD4(+)CD25(++bright)Foxp3(+) phenotype,had potent functional ability to suppress CD4(+)CD25(negative) T cells without evidence of conversion to effector T cells including TH17 cells,and manifested little to no production of pro-inflammatory cytokines upon in vitro stimulation. Boolean gating analysis of cytokine-expressing cells by flow cytometry for 32 possible profile end points revealed that 96% of expanded nTregs did not express any cytokine. From a single buffy coat,approximately 80 million pure nTregs were harvested after expansion under cGMP conditions; these cell numbers are adequate for infusion of approximately one million cells kg�?�¹ for cell therapy in clinical trials. View Publication