技术资料

Lipoproteins modulate innate and adaptive immune responses. In the chronic inflammatory disease multiple sclerosis (MS),reports on lipoprotein level alterations are inconsistent and it is unclear whether lipoprotein function is affected. Using nuclear magnetic resonance (NMR) spectroscopy,we analysed the lipoprotein profile of relapsing-remitting (RR) MS patients,progressive MS patients and healthy controls (HC). We observed smaller LDL in RRMS patients compared to healthy controls and to progressive MS patients. Furthermore,low-BMI (BMI ≤ 23 kg/m(2)) RRMS patients show increased levels of small HDL (sHDL),accompanied by larger,triglyceride (TG)-rich VLDL,and a higher lipoprotein insulin resistance (LP-IR) index. These alterations coincide with a reduced serum capacity to accept cholesterol via ATP-binding cassette (ABC) transporter G1,an impaired ability of HDL3 to suppress inflammatory activity of human monocytes,and modifications of HDL3's main protein component ApoA-I. In summary,lipoprotein levels and function are altered in RRMS patients,especially in low-BMI patients,which may contribute to disease progression in these patients. View Publication

OBJECTIVE Vitamin D deficiency has been linked to increased risk of multiple sclerosis (MS) and poor outcome. However,the specific role that vitamin D plays in MS still remains unknown. In order to identify potential mechanisms underlying vitamin D effects in MS,we profiled epigenetic changes in vitamin D receptor (VDR) gene to identify genomic regulatory elements relevant to MS pathogenesis. METHODS Human T cells derived from whole blood by negative selection were isolated in a set of 23 relapsing-remitting MS (RRMS) patients and 12 controls matched by age and gender. DNA methylation levels were assessed by bisulfite cloning sequencing in two regulatory elements of VDR. mRNA levels were measured by RT-qPCR to assess changes in VDR expression between patients and controls. RESULTS An alternative VDR promoter placed at exon 1c showed increased DNA methylation levels in RRMS patients (median 30.08%,interquartile range 19.2%) compared to controls (18.75%,9.5%),p-valuetextless0.05. Moreover,a 6.5-fold increase in VDR mRNA levels was found in RRMS patients compared to controls (p-valuetextless0.001). CONCLUSIONS An alternative promoter of the VDR gene shows altered DNA methylation levels in patients with multiple sclerosis,and it is associated with VDR mRNA upregulation. This locus may represent a candidate regulatory element in the genome relevant to MS pathogenesis. View Publication

Affinity- and stability-engineered variants of CTLA4-Ig fusion molecules with enhanced pharmacokinetic profiles could yield improved therapies with the potential of higher efficacy and greater convenience to patients. In this study,to our knowledge,we have,for the first time,used in vitro evolution to simultaneously optimize CTLA4 affinity and stability. We selected for improved binding to both ligands,CD80 and CD86,and screened as dimeric Fc fusions directly in functional assays to identify variants with stronger suppression of in vitro T cell activation. The majority of CTLA4 molecules showing the largest potency gains in primary in vitro and ex vivo human cell assays,using PBMCs from type 1 diabetes patients,had significant improvements in CD80,but only modest gains in CD86 binding. We furthermore observed different potency rankings between our lead molecule MEDI5265,abatacept,and belatacept,depending on which type of APC was used,with MEDI5265 consistently being the most potent. We then created fusions of both stability- and potency-optimized CTLA4 moieties with human Fc variants conferring extended plasma t1/2 In a cynomolgus model of T cell-dependent Ab response,the CTLA4-Ig variant MEDI5265 could be formulated at textgreater100 mg/ml for s.c. administration and showed superior efficacy and significantly prolonged serum t1/2 The combination of higher stability and potency with prolonged pharmacokinetics could be compatible with very infrequent,s.c. dosing while maintaining a similar level of immune suppression to more frequently and i.v. administered licensed therapies. View Publication

While a third of the world carries the burden of tuberculosis,disease control has been hindered by a lack of tools,including a rapid,point-of-care diagnostic and a protective vaccine. In many infectious diseases,antibodies (Abs) are powerful biomarkers and important immune mediators. However,in Mycobacterium tuberculosis (Mtb) infection,a discriminatory or protective role for humoral immunity remains unclear. Using an unbiased antibody profiling approach,we show that individuals with latent tuberculosis infection (Ltb) and active tuberculosis disease (Atb) have distinct Mtb-specific humoral responses,such that Ltb infection is associated with unique Ab Fc functional profiles,selective binding to FcγRIII,and distinct Ab glycosylation patterns. Moreover,compared to Abs from Atb,Abs from Ltb drove enhanced phagolysosomal maturation,inflammasome activation,and,most importantly,macrophage killing of intracellular Mtb. Combined,these data point to a potential role for Fc-mediated Ab effector functions,tuned via differential glycosylation,in Mtb control. View Publication

Type 1 diabetes (T1D) is characterized by a chronic,progressive autoimmune attack against pancreas-specific antigens,effecting the destruction of insulin-producing β-cells. Here we show interleukin-2 (IL-2) is a non-pancreatic autoimmune target in T1D. Anti-IL-2 autoantibodies,as well as T cells specific for a single orthologous epitope of IL-2,are present in the peripheral blood of non-obese diabetic (NOD) mice and patients with T1D. In NOD mice,the generation of anti-IL-2 autoantibodies is genetically determined and their titre increases with age and disease onset. In T1D patients,circulating IgG memory B cells specific for IL-2 or insulin are present at similar frequencies. Anti-IL-2 autoantibodies cloned from T1D patients demonstrate clonality,a high degree of somatic hypermutation and nanomolar affinities,indicating a germinal centre origin and underscoring the synergy between cognate autoreactive T and B cells leading to defective immune tolerance. View Publication

New genetic tools are needed to understand the functional interactions between HIV and human host factors in primary cells. We recently developed a method to edit the genome of primary CD4(+) T cells by electroporation of CRISPR/Cas9 ribonucleoproteins (RNPs). Here,we adapted this methodology to a high-throughput platform for the efficient,arrayed editing of candidate host factors. CXCR4 or CCR5 knockout cells generated with this method are resistant to HIV infection in a tropism-dependent manner,whereas knockout of LEDGF or TNPO3 results in a tropism-independent reduction in infection. CRISPR/Cas9 RNPs can furthermore edit multiple genes simultaneously,enabling studies of interactions among multiple host and viral factors. Finally,in an arrayed screen of 45 genes associated with HIV integrase,we identified several candidate dependency/restriction factors,demonstrating the power of this approach as a discovery platform. This technology should accelerate target validation for pharmaceutical and cell-based therapies to cure HIV infection. View Publication

The extrafollicular (EF) plasmablast response to self-antigens that contain Toll-like receptor (TLR) ligands is prominent in murine lupus models and some bacterial infections,but the inhibitors and activators involved have not been fully delineated. Here,we used two conventional dendritic cell (cDC) depletion systems to investigate the role of cDCs on a classical TLR-dependent autoreactive EF response elicited in rheumatoid-factor B cells by DNA-containing immune complexes. Contrary to our hypothesis,cDC depletion amplified rather than dampened the EF response in Fas-intact but not Fas-deficient mice. Further,we demonstrated that cDC-dependent regulation requires Fas and Fas ligand (FasL) expression by T cells,but not Fas expression by B cells. Thus,cDCs activate FasL-expressing T cells that regulate Fas-expressing extrafollicular helper T (Tefh) cells. These studies reveal a regulatory role for cDCs in B cell plasmablast responses and provide a mechanistic explanation for the excess autoantibody production observed in Fas deficiency. View Publication

BACKGROUND/AIM Live attenuated vaccines confer partial protection in pigs before the appearance of neutralizing antibodies,suggesting the contribution of cell-mediated immunity (CMI). However,PRRSV-specific T-lymphocyte responses and protective mechanisms need to be further defined. To this end,the hypothesis was tested that PRRSV-specific T-lymphocytes induced by exposure to type-2 PRRSV can recognize diverse isolates. METHODS An IFN-gamma ELISpot assay was used to enumerate PRRSV-specific T-lymphocytes from PRRSVSD23983-infected gilts and piglets born after in utero infection against 12 serologically and genetically distinct type-1 and -2 PRRSV isolates. The IFN-gamma ELISpot assay using synthetic peptides spanning all open reading frames of PRRSVSD23983 was utilized to localize epitopes recognized by T-lymphocytes. Virus neutralization tests were carried out using the challenge strain (type-2 PRRSVSD23983) and another strain (type-2 PRRSVVR2332) with high genetic similarity to evaluate cross-reactivity of neutralizing antibodies in gilts after PRRSVSD23983 infection. RESULTS At 72 days post infection,T-lymphocytes from one of three PRRSVSD23983-infected gilts recognized all 12 diverse PRRSV isolates,while T-lymphocytes from the other two gilts recognized all but one isolate. Furthermore,five of nine 14-day-old piglets infected in utero with PRRSVSD23983 had broadly reactive T-lymphocytes,including one piglet that recognized all 12 isolates. Overlapping peptides encompassing all open reading frames of PRRSVSD23983 were used to identify ≥28 peptides with T-lymphocyte epitopes from 10 viral proteins. This included one peptide from the M protein that was recognized by T-lymphocytes from all three gilts representing two completely mismatched MHC haplotypes. In contrast to the broadly reactive T-lymphocytes,neutralizing antibody responses were specific to the infecting PRRSVSD23983 isolate. CONCLUSION These results demonstrated that T-lymphocytes recognizing antigenically and genetically diverse isolates were induced by infection with a type 2 PRRSV strain (SD23983). If these reponses have cytotoxic or other protective functions,they may help overcome the suboptimal heterologous protection conferred by conventional vaccines. View Publication

Dendritic cells (DCs) are antigen presenting cells of the immune system that play a crucial role in lymphocyte responses,host defense mechanisms,and pathogenesis of inflammation. Isolation and study of DCs have been important in biological research because of their distinctive features. Although they are essential key mediators of the immune system,DCs are very rare in blood,accounting for approximately 0.1 - 1% of total blood mononuclear cells. Therefore,alternatives for isolation methods rely on the differentiation of DCs from monocytes isolated from peripheral blood mononuclear cells (PBMCs). The utilization of proper isolation techniques that combine simplicity,affordability,high purity,and high yield of cells is imperative to consider. In the current study,two distinct methods for the generation of DCs will be compared. Monocytes were selected by adherence or negatively enriched using magnetic separation procedure followed by differentiation into DCs with IL-4 and GM-CSF. Monocyte and MDDC viability,proliferation,and phenotype were assessed using viability dyes,MTT assay,and CD11c/ CD14 surface marker analysis by imaging flow cytometry. Although the magnetic separation method yielded a significant higher percentage of monocytes with higher proliferative capacity when compared to the adhesion method,the findings have demonstrated the ability of both techniques to simultaneously generate monocytes that are capable of proliferating and differentiating into viable CD11c+ MDDCs after seven days in culture. Both methods yielded textgreater 70% CD11c+ MDDCs. Therefore,our results provide insights that contribute to the development of reliable methods for isolation and characterization of human DCs. View Publication

Autologous platelet rich plasma (PRP) is clinically used to induce repair of different tissues through the release of bioactive molecules. In some patients,the production of an efficient autologous PRP is unfeasible due to their compromised health. We developed an allogeneic PRP mismatched for AB0 and Rh antigens. To broadcast its clinical applications avoiding side effects the outcome of allogeneic PRP on immune response should be defined. Thus,we investigated whether PRP affected the differentiation of peripheral blood monocytes to dendritic cells upon stimulation with granulocyte monocyte colony stimulating factor and interleukin-4. Indeed,these cells are the main players of immune response and tissue repair. PRP inhibited the differentiation of monocytes to CD1a(+) dendritic cells and favored the expansion of phagocytic CD163(+) CD206(+) fibrocyte-like cells. These cells produced inteleukin-10 and prostaglandin-E2,but not interferon-γ,upon stimulation with lipopolysaccharides. Moreover,they promoted the expansion of regulatory CD4(+) CD25(+) FoxP3(+) T cells upon allostimulation or antigen specific priming. Finally,the conditioned medium harvested from monocytes differentiated with PRP triggered a strong chemotactic effect on mesenchymal cells in both scratch and transwell migration assays. These results strongly suggest that allogeneic PRP can foster the differentiation of monocytes to a regulatory anti-inflammatory population possibly favoring wound healing. View Publication

The ability of a cancer cell to migrate through the dense extracellular matrix (ECM) within and surrounding the solid tumor is a critical determinant of metastasis. Macrophages enhance invasion and metastasis in the tumor microenvironment but the basis for their effects are not fully understood. Using a microfluidic 3D cell migration assay,we found that the presence of macrophages enhanced the speed and persistence of cancer cell migration through a 3D extracellular matrix in a matrix metalloproteinases (MMP)-dependent fashion. Mechanistic investigations revealed that macrophage-released TNFα and TGFβ1 mediated the observed behaviors by two distinct pathways. These factors synergistically enhanced migration persistence through a synergistic induction of NF-κB-dependent MMP1 expression in cancer cells. In contrast,macrophage-released TGFβ1 enhanced migration speed primarily by inducing MT1-MMP expression. Taken together,our results reveal new insights into how macrophages enhance cancer cell metastasis,and they identify TNFα and TGFβ1 dual blockade as an anti-metastatic strategy in solid tumors. View Publication

Increasing amounts of pathogen replication usually lead to a proportionate increase in size and effector differentiation of the CD8(+) T cell response,which is attributed to increased Ag and inflammation. Using a murine CMV that is highly sensitive to the antiviral drug famciclovir to modulate virus replication,we found that increased virus replication drove increased effector CD8(+) T cell differentiation,as expected. Paradoxically,however,increased virus replication dramatically decreased the size of the CD8(+) T cell response to two immunodominant epitopes. The decreased response was due to type I IFN-dependent depletion of conventional dendritic cells and could be reproduced by specific depletion of dendritic cells from day 2 postinfection or by sterile induction of type I IFN. Increased virus replication and type I IFN specifically inhibited the response to two immunodominant epitopes that are known to be dependent on Ag cross-presented by DCs,but they did not inhibit the response to inflationary" epitopes whose responses can be sustained by infected nonhematopoietic cells. Our results show that type I IFN can suppress CD8(+) T cell responses to cross-presented Ag by depleting cross-presenting conventional dendritic cells." View Publication