技术资料

Sialic acids are negatively charged carbohydrates that cap the glycans of glycoproteins and glycolipids. Sialic acids are involved in various biological processes including cell-cell adhesion and immune recognition. In dendritic cells (DCs),the major antigen-presenting cells of the immune system,sialic acids emerge as important regulators of maturation and interaction with other lymphocytes including T cells. Many aspects of how sialic acids regulate DC functions are not well understood and tools and model systems to address these are limited. Here,we have established cultures of murine bone marrow-derived DCs (BMDCs) that lack sialic acid expression using a sialic acid-blocking mimetic Ac53FaxNeu5Ac. Ac53FaxNeu5Ac treatment potentiated BMDC activation via toll-like receptor (TLR) stimulation without affecting differentiation and viability. Sialic acid blockade further increased the capacity of BMDCs to induce antigen-specific CD8+ T cell proliferation. Transcriptome-wide gene expression analysis revealed that sialic acid mimetic treatment of BMDCs induces differential expression of genes involved in T cell activation,cell-adhesion,and cell-cell interactions. Subsequent cell clustering assays and single cell avidity measurements demonstrated that BMDCs with reduced sialylation form higher avidity interactions with CD8+ T cells. This increased avidity was detectable in the absence of antigens,but was especially pronounced in antigen-dependent interactions. Together,our data show that sialic acid blockade in BMDCs ameliorates maturation and enhances both cognate T cell receptor-MHC-dependent and independent T cell interactions that allow for more robust CD8+ T cell responses. View Publication

A subset of antibodies found in cattle comprises ultralong CDR-H3 regions of up to 70 amino acids. Interestingly,this type of immunoglobulin usually pairs with the single germline VL gene,V30 that is typically very conserved in sequence. In this work,we have engineered ultralong CDR-H3 common light chain bispecific antibodies targeting Epidermal Growth Factor Receptor (EGFR) on tumor cells as well as Natural Cytotoxicity Receptor NKp30 on Natural Killer (NK) cells. Antigen-specific common light chain antibodies were isolated by yeast surface display by means of pairing CDR-H3 diversities following immunization with a single V30 light chain. After selection,EGFR-targeting paratopes as well as NKp30-specific binders were combined into common light chain bispecific antibodies by exploiting the strand-exchange engineered domain (SEED) technology for heavy chain heterodimerization. Biochemical characterization of resulting bispecifics revealed highly specific binding to the respective antigens as well as simultaneous binding to both targets. Most importantly,engineered cattle-derived bispecific common light chain molecules elicited potent NK cell redirection and consequently tumor cell lysis of EGFR-overexpressing cells as well as robust release of proinflammatory cytokine interferon-$\gamma$. Taken together,this data is giving clear evidence that bovine bispecific ultralong CDR-H3 common light chain antibodies are versatile for biotechnological applications. View Publication

Oncogenic activated RAS mutations have been detected in 50% of de novo and 70% of relapsed multiple myeloma (MM) patients. Translocation t(11;14) involving IgH/CCDN1 and overexpression of cyclin-Ds are early events in MM pathogenesis,enhancing uncontrolled MM cell growth. We hypothesized that targeting both RAS/MAPK pathway molecules including Erk1/2 along with cyclin-Ds enhances MM cytotoxicity and minimizes side effects. Recent studies have demonstrated the high potency of Erk1/2 and CDK4/6 inhibitors in metastatic relapsed cancers,and here we tested anti-MM effects of the Erk1/2??+??CDK4/6 inhibitor combination. Our studies showed strong synergistic (IC?? View Publication

Solid tumor cells have an altered metabolism that can protect them from cytotoxic lymphocytes. The anti-diabetic drug metformin modifies tumor cell metabolism and several clinical trials are testing its effectiveness for the treatment of solid cancers. The use of metformin in hematologic cancers has received much less attention,although allogeneic cytotoxic lymphocytes are very effective against these tumors. We show here that metformin induces expression of Natural Killer G2-D (NKG2D) ligands (NKG2DL) and intercellular adhesion molecule-1 (ICAM-1),a ligand of the lymphocyte function-associated antigen 1 (LFA-1). This leads to enhance sensitivity to cytotoxic lymphocytes. Overexpression of anti-apoptotic Bcl-2 family members decrease both metformin effects. The sensitization to activated cytotoxic lymphocytes is mainly mediated by the increase on ICAM-1 levels,which favors cytotoxic lymphocytes binding to tumor cells. Finally,metformin decreases the growth of human hematological tumor cells in xenograft models,mainly in presence of monoclonal antibodies that recognize tumor antigens. Our results suggest that metformin could improve cytotoxic lymphocyte-mediated therapy. View Publication

HLA-DQ donor-specific antibodies (DSA) are the most prevalent type of DSA after renal transplantation and have been associated with eplet mismatches between donor and recipient HLA. Eplets are theoretically defined configurations of surface exposed amino acids on HLA molecules that require verification to confirm that they can be recognized by alloantibodies and are therefore clinically relevant. In this study,we isolated HLA-DQ specific memory B cells from immunized individuals by using biotinylated HLA-DQ monomers to generate 15 recombinant human HLA-DQ specific monoclonal antibodies (mAb) with six distinct specificities. Single antigen bead reactivity patterns were analyzed with HLA-EMMA to identify amino acids that were uniquely shared by the reactive HLA alleles to define functional epitopes which were mapped to known eplets. The HLA-DQB1*03:01-specific mAb LB_DQB0301_A and the HLA-DQB1*03-specific mAb LB_DQB0303_C supported the antibody-verification of eplets 45EV and 55PP respectively,while mAbs LB_DQB0402_A and LB_DQB0602_B verified eplet 55R on HLA-DQB1*04/05/06. For three mAbs,multiple uniquely shared amino acid configurations were identified,warranting further studies to define the inducing functional epitope and corresponding eplet. Our unique set of HLA-DQ specific mAbs will be further expanded and will facilitate the in-depth analysis of HLA-DQ epitopes,which is relevant for further studies of HLA-DQ alloantibody pathogenicity in transplantation. View Publication

Our previous studies have shown that ethanol intoxication combined with burn injury increases intestinal bacterial growth,disrupts the intestinal barrier,and enhances bacterial translocation. Additionally,studies show that Th17 effector cytokines IL-17 and IL-22,which are dependent on IL-23,play important roles in maintaining intestine mucosal barrier integrity. Recent findings suggest neutrophils are a significant source of IL-17 and IL-22. We determined the effect of ethanol and burn injury on neutrophil IL-17 and IL-22 production,as well as their ability to phagocytose and in bacterial clearance,and whether these effects are modulated by IL-23. Mice were given ethanol 4 h prior to receiving ˆ¼12.5% total body surface area burn and were euthanized day 1 after injury. We observed that intoxication combined with burn injury significantly decreases blood neutrophil phagocytosis and bacteria killing,as well as their ability to produce IL-17 and IL-22,compared with sham vehicle mice. The treatment of neutrophils with rIL-23 significantly increases IL-22 and IL-17 release and promotes expression of IL-23R,retinoic acid-related orphan receptor $\gamma$t,Lipocalin2,and Nod-like receptor 2 following ethanol and burn injury. Furthermore,IL-22- and IL-17-producing neutrophils have enhanced neutrophil extracellular trap formation and bacterial killing ability,which are dependent on IL-23. Finally,although we observed that peritoneal neutrophils harvested after casein treatment are functionally different from blood neutrophils,both blood and peritoneal neutrophils exhibited the same response to rIL-23 treatment. Together these findings suggest that IL-23 promotes neutrophil IL-22 and IL-17 production and their ability to kill bacteria following ethanol and burn injury. View Publication

Chimeric antigen receptor (CAR) T cells targeting CD19 mediate potent antitumor effects in B-cell malignancies including acute lymphoblastic leukemia (ALL),but antigen loss remains the major cause of treatment failure. To mitigate antigen escape and potentially improve the durability of remission,we developed a dual-targeting approach using an optimized,bispecific CAR construct that targets both CD19 and BAFF-R. CD19/BAFF-R dual CAR T cells exhibited antigen-specific cytokine release,degranulation,and cytotoxicity against both CD19-/- and BAFF-R-/- variant human ALL cells in vitro. Immunodeficient mice engrafted with mixed CD19-/- and BAFF-R-/- variant ALL cells and treated with a single dose of CD19/BAFF-R dual CAR T cells experienced complete eradication of both CD19-/- and BAFF-R-/- ALL variants,whereas mice treated with monospecific CD19 or BAFF-R CAR T cells succumbed to outgrowths of CD19-/BAFF-R+ or CD19+/BAFF-R- tumors,respectively. Further,CD19/BAFF-R dual CAR T cells showed prolonged in vivo persistence,raising the possibility that these cells may have the potential to promote durable remissions. Together,our data support clinical translation of BAFF-R/CD19 dual CAR T cells to treat ALL. View Publication

Cystic fibrosis (CF) is an inherited life-threatening disease accompanied by repeated lung infections and multiorgan inflammation that affects tens of thousands of people worldwide. The causative gene,cystic fibrosis transmembrane conductance regulator (CFTR),is mutated in CF patients. CFTR functions in epithelial cells have traditionally been thought to cause the disease symptoms. Recent work has shown an additional defect: monocytes from CF patients show a deficiency in integrin activation and adhesion. Because monocytes play critical roles in controlling infections,defective monocyte function may contribute to CF progression. In this study,we demonstrate that monocytes from CFTR$\Delta$F508 mice (CF mice) show defective adhesion under flow. Transplanting CF mice with wild-type (WT) bone marrow after sublethal irradiation replaced most (60-80%) CF monocytes with WT monocytes,significantly improved survival,and reduced inflammation. WT/CF mixed bone marrow chimeras directly demonstrated defective CF monocyte recruitment to the bronchoalveolar lavage and the intestinal lamina propria in vivo. WT mice reconstituted with CF bone marrow also show lethality,suggesting that the CF defect in monocytes is not only necessary but also sufficient to cause disease. We also show that monocyte-specific knockout of CFTR retards weight gains and exacerbates dextran sulfate sodium-induced colitis. Our findings show that providing WT monocytes by bone marrow transfer rescues mortality in CF mice,suggesting that similar approaches may mitigate disease in CF patients. View Publication

Low-density neutrophils (LDNs) have been described in tumors and various autoimmune diseases,where they exhibit immune dysfunction and alter disease progression. Nevertheless,LDNs have been rarely reported in sepsis. We studied sepsis patients admitted to the intensive care unit. Wright-Giemsa stain assay and Transmission electron microscopy were performed to detect the morphology of neutrophils. Flow cytometry was used to analyze the number and function of LDNs. Concentration of cytokines was measured using ELISA. Neutrophil chemotaxis was examined using an under-agarose chemotaxis model. We found that LDNs were significantly elevated in patients with sepsis. Phenotypes and morphological characteristics suggest that LDNs may be formed by mixtures of neutrophils at various maturation stages. In vitro experiments showed that LDN formation was closely associated with neutrophil degranulation. We preliminarily discussed changes in immune function in LDNs. Compared with high-density neutrophils,expression levels of CXC chemokine receptor 4 on LDN surfaces were increased,phagocytotic capacity was decreased,and life span was prolonged. The chemotactic ability of LDNs was significantly reduced,possibly related to the increased expression of P2X1. These data suggest that LDNs are essential components of neutrophils in sepsis. To clarify the source and dysfunction mechanism of LDN in sepsis may be helpful for the diagnosis and treatment of sepsis in the future. View Publication

BACKGROUND Adoptive T-cell transfer has become an attractive therapeutic approach for hematological malignancies but shows poor activity against large and heterogeneous solid tumors. Interleukin-12 (IL-12) exhibits potent antitumor efficacy against solid tumors,but its clinical application has been stalled because of toxicity. Here,we aimed to develop a safe approach to IL-12 T-cell therapy for eliminating large solid tumors. METHODS We generated a cell membrane-anchored IL-12 (aIL12),a tumor-targeted IL-12 (ttIL12),and a cell membrane-anchored and ttIL-12 (attIL12) and a cell membrane-anchored and tumor-targeted ttIL-12 (attIL12) armed T cells,chimeric antigen receptor-T cells,and T cell receptor-T (TCR-T) cells with each. We compared the safety and efficacy of these armed T cells in treating osteosarcoma patient-derived xenograft tumors and mouse melanoma tumors after intravenous infusions of the armed T cells. RESULTS attIL12-T cell infusion showed remarkable antitumor efficacy in human and mouse large solid tumor models. Mechanistically,attIL12-T cells targeted tumor cells expressing cell-surface vimentin,enriching effector T cell and interferon $\gamma$ production in tumors,which in turn stimulates dendritic cell maturation for activating secondary T-cell responses and tumor antigen spreading. Both attIL12- and aIL12-T-cell transfer eliminated peripheral cytokine release and the associated toxic effects. CONCLUSIONS This novel approach sheds light on the safe application of IL-12-based T-cell therapy for large and heterogeneous solid tumors. View Publication

Early erythroid progenitors are transit-amplifying cells with high proliferative capacity committed to undergoing red cell differentiation. CD71/CD24low progenitors are less mature and have greater proliferative capacity than CD71/CD24high. We present protocols for isolation of CD71/CD24low progenitors from mouse fetal liver using both fluorescence-activated cell sorting (FACS) and immunomagnetic enrichment. CD71/CD24low progenitors isolated with both approaches show similar transcriptomes at single-cell resolution and exhibit characteristic proliferative responses to glucocorticoids. For complete details on the use and execution of this protocol,please refer to Li et al. (2019). View Publication

MicroRNAs (miRNAs/miRs) are small,endogenous noncoding RNAs that are important post-transcriptional regulators with clear roles in the development of the immune system and immune responses. Using miRNA microarray profiling,we characterized the expression profile of naive and in vivo generated murine effector antiviral CD8+ T cells. We observed that out of 362 measurable mature miRNAs,120 were differentially expressed by at least 2-fold in influenza-specific effector CD8+ CTLs compared with naive CD8+ T cells. One miRNA found to be highly downregulated on both strands in effector CTLs was miR-139. Because previous studies have indicated a role for miR-139-mediated regulation of CTL effector responses,we hypothesized that deletion of miR-139 would enhance antiviral CTL responses during influenza virus infection. We generated miR-139-/- mice or overexpressed miR-139 in T cells to assess the functional contribution of miR-139 expression in CD8+ T cell responses. Our study demonstrates that the development of naive T cells and generation or differentiation of effector or memory CD8+ T cell responses to influenza virus infection are not impacted by miR-139 deficiency or overexpression; yet,miR-139-/- CD8+ T cells are outcompeted by wild-type CD8+ T cells in a competition setting and demonstrate reduced responses to Listeria monocytogenes Using an in vitro model of T cell exhaustion,we confirmed that miR-139 expression similarly does not impact the development of T cell exhaustion. We conclude that despite significant downregulation of miR-139 following in vivo and in vitro activation,miR-139 expression is dispensable for influenza-specific CTL responses. View Publication