技术资料

B cells play an important role in type 1 diabetes (T1D) development. However,the role of B cell activation-induced cytidine deaminase (AID) in diabetes development is not clear. We hypothesized that AID is important in the immunopathogenesis of T1D. To test this hypothesis,we generated AID-deficient (AID-/-) NOD mice. We found that AID-/-NOD mice developed accelerated T1D,with worse insulitis and high levels of anti-insulin autoantibody in the circulation. Interestingly,neither maternal IgG transferred through placenta,nor IgA transferred through milk affected the accelerated diabetes development. AID-/-NOD mice showed increased activation and proliferation of B and T cells. We found enhanced T-B cell interactions in AID-/-NOD mice,with increased T-bet and IFN-γ expression in CD4+ T cells in the presence of AID-/- B cells. Moreover,excessive lymphoid expansion was observed in AID-/-NOD mice. Importantly,antigen-specific BDC2.5 CD4+ T cells caused more rapid onset of diabetes when cotransferred with AID-/- B cells than when cotransferred with AID+/+ B cells. Thus,our study provides insights into the role of AID in T1D. Our data also suggest that AID is a negative regulator of immune tolerance and ablation of AID can lead to exacerbated islet autoimmunity and accelerated T1D development. View Publication

Improved understanding of expression of immune checkpoint receptors (ICR) on tumor-infiltrating lymphocytes (TIL) may facilitate more effective immunotherapy in head and neck cancer (HNC) patients. A higher frequency of PD-1+ TIL has been reported in human papillomavirus (HPV)+ HNC patients,despite the role of PD-1 in T-cell exhaustion. This discordance led us to hypothesize that the extent of PD-1 expression more accurately defines T-cell function and prognostic impact,because PD-1high T cells may be more exhausted than PD-1low T cells and may influence clinical outcome and response to anti-PD-1 immunotherapy. In this study,PD-1 expression was indeed upregulated on HNC patient TIL,and the frequency of these PD-1+ TIL was higher in HPV+ patients (P = 0.006),who nonetheless experienced significantly better clinical outcome. However,PD-1high CD8+ TILs were more frequent in HPV- patients and represented a more dysfunctional subset with compromised IFN-γ secretion. Moreover,HNC patients with higher frequencies of PD-1high CD8+ TIL showed significantly worse disease-free survival and higher hazard ratio for recurrence (P < 0.001),while higher fractions of PD-1low T cells associated with HPV positivity and better outcome. In a murine HPV+ HNC model,anti-PD-1 mAb therapy differentially modulated PD-1high/low populations,and tumor rejection associated with loss of dysfunctional PD-1high CD8+ T cells and a significant increase in PD-1low TIL. Thus,the extent of PD-1 expression on CD8+ TIL provides a potential biomarker for anti-PD-1-based immunotherapy. Cancer Res; 77(22); 6353-64. textcopyright2017 AACR. View Publication

Dendritic cells (DCs) are a heterogeneous population of professional antigen-presenting cells and are key cells of the immune system,acquiring different phenotypes in accordance with their localization during the immune response. A subset of inflammatory DCs is derived from circulating monocytes (Mo) and has a key role in inflammation and infection. The pathways controlling Mo-DC differentiation are not fully understood. Our objective was to investigate the possible role of nicotinamide adenine dinucleotide phosphate reduced form oxidases (NOXs) in Mo-DC differentiation. In this study,we revealed that Mo-DC differentiation was inhibited by NOX inhibitors and reactive oxygen species scavengers. We show that the Mo-DC differentiation was dependent on p22phox,and not on gp91phox/NOX2,as shown by the reduced Mo-DC differentiation observed in chronic granulomatous disease patients lacking p22phox. Moreover,we revealed that NOX5 expression was strongly increased during Mo-DC differentiation,but not during Mo-macrophage differentiation. NOX5 was expressed in circulating myeloid DC,and at a lower level in plasmacytoid DC. Interestingly,NOX5 was localized at the outer membrane of the mitochondria and interacted with p22phox in Mo-DC. Selective inhibitors and small interfering RNAs for NOX5 indicated that NOX5 controlled Mo-DC differentiation by regulating the JAK/STAT/MAPK and NFκB pathways. These data demonstrate that the NOX5-p22phox complex drives Mo-DC differentiation,and thus could be critical for immunity and inflammation. View Publication

The maintenance of peripheral naive T lymphocytes in humans is dependent on their homeostatic division,not continuing emigration from the thymus,which undergoes involution with age. However,postthymic maintenance of naive T cells is still poorly understood. Previously we reported that recent thymic emigrants (RTEs) are contained in CD31+CD25- naive T cells as defined by their levels of signal joint T cell receptor rearrangement excision circles (sjTRECs). Here,by differential gene expression analysis followed by protein expression and functional studies,we define that the naive T cells having divided the least since thymic emigration express complement receptors (CR1 and CR2) known to bind complement C3b- and C3d-decorated microbial products and,following activation,produce IL-8 (CXCL8),a major chemoattractant for neutrophils in bacterial defense. We also observed an IL-8-producing memory T cell subpopulation coexpressing CR1 and CR2 and with a gene expression signature resembling that of RTEs. The functions of CR1 and CR2 on T cells remain to be determined,but we note that CR2 is the receptor for Epstein-Barr virus,which is a cause of T cell lymphomas and a candidate environmental factor in autoimmune disease. View Publication

Inhibition of cytosolic DNA sensing represents a strategy that tumor cells use for immune evasion,but the underlying mechanisms are unclear. Here we have shown that CD47-signal regulatory protein α (SIRPα) axis dictates the fate of ingested DNA in DCs for immune evasion. Although macrophages were more potent in uptaking tumor DNA,increase of DNA sensing by blocking the interaction of SIRPα with CD47 preferentially occurred in dendritic cells (DCs) but not in macrophages. Mechanistically,CD47 blockade enabled the activation of NADPH oxidase NOX2 in DCs,which in turn inhibited phagosomal acidification and reduced the degradation of tumor mitochondrial DNA (mtDNA) in DCs. mtDNA was recognized by cyclic-GMP-AMP synthase (cGAS) in the DC cytosol,contributing to type I interferon (IFN) production and antitumor adaptive immunity. Thus,our findings have demonstrated how tumor cells inhibit innate sensing in DCs and suggested that the CD47-SIRPα axis is critical for DC-driven antitumor immunity. 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

The adaptive immune response involves T cell differentiation and migration to sites of inflammation. T cell trafficking is initiated by rolling on inflamed endothelium. Tethers and slings,discovered in neutrophils,facilitate cell rolling at high shear stress. Here,we demonstrate that the ability to form tethers and slings during rolling is highly inducible in T helper 1 (Th1),Th17,and regulatory T (Treg) cells but less in Th2 cells. In vivo,endogenous Treg cells rolled stably in cremaster venules at physiological shear stress. Quantitative dynamic footprinting nanoscopy of Th1,Th17,and Treg cells uncovered the formation of multiple tethers per cell. Human Th1 cells also showed tethers and slings. RNA sequencing (RNA-seq) revealed the induction of cell migration and cytoskeletal genes in sling-forming cells. We conclude that differentiated CD4 T cells stabilize rolling by inducible tether and sling formation. These phenotypic changes approximate the adhesion phenotype of neutrophils and support CD4 T cell access to sites of inflammation. View Publication