搜索结果: 'methocult media formulations for human hematopoietic cells serum containing'

Specific antibody opsonization significantly enhances the level of phagocytosis of Candida in the absence of complement. Furthermore,we have described a system using a recombinant human antibody single-chain variable fragment that allows a comparative study of phagocytosis of multiple Candida species opsonized via a common antigen. View Publication

The presence of interleukin-2 (IL-2)-producing human immunodeficiency virus type 1 (HIV-1)-specific CD4(+) T-cell responses has been associated with the immunological control of HIV-1 replication; however,the causal relationship between these factors remains unclear. Here we show that IL-2-producing HIV-1-specific CD4(+) T cells can be cloned from acutely HIV-1-infected individuals. Despite the early presence of these cells,each of the individuals in the present study exhibited progressive disease,with one individual showing rapid progression. In this rapid progressor,three IL-2-producing HIV-1 Gag-specific CD4(+) T-cell responses were identified and mapped to the following optimal epitopes: HIVWASRELER,REPRGSDIAGT,and FRDYVDRFYKT. Responses to these epitopes in peripheral blood mononuclear cells were monitored longitudinally to textgreater1 year postinfection,and contemporaneous circulating plasma viruses were sequenced. A variant of the FRDYVDRFYKT epitope sequence,FRDYVDQFYKT,was observed in 1/21 plasma viruses sequenced at 5 months postinfection and 1/10 viruses at 7 months postinfection. This variant failed to stimulate the corresponding CD4(+) T-cell clone and thus constitutes an escape mutant. Responses to each of the three Gag epitopes were rapidly lost,and this loss was accompanied by a loss of antigen-specific cells in the periphery as measured by using an FRDYVDRFYKT-presenting major histocompatibility complex class II tetramer. Highly active antiretroviral therapy was associated with the reemergence of FRDYVDRFYKT-specific cells by tetramer. Thus,our data support that IL-2-producing HIV-1-specific CD4(+) T-cell responses can exert immune pressure during early HIV-1 infection but that the inability of these responses to enforce enduring control of viral replication is related to the deletion and/or dysfunction of HIV-1-specific CD4(+) T cells rather than to the fixation of escape mutations at high frequencies. View Publication

CD4 and CD8 T lymphocyte activation requires the generation of sufficient energy to support new biosynthetic demands. Following T cell receptor (TCR) engagement,these requirements are met by an increased glycolysis,due,at least in part,to induction of the Glut1 glucose transporter. As Glut1 is upregulated on tumor cells in response to hypoxia,we assessed whether surface Glut1 levels regulate the antigen responsiveness of human T lymphocytes in both hypoxic and atmospheric oxygen conditions. Notably,Glut1 upregulation in response to TCR stimulation was significantly higher in T lymphocytes activated under hypoxic as compared to atmospheric oxygen conditions. Furthermore,TCR-stimulated human T lymphocytes sorted on the basis of Glut1-Lo and Glut1-Hi profiles maintained distinct characteristics,irrespective of the oxygen tension. While T cells activated in hypoxia divided less than those activated in atmospheric oxygen,Glut1-Hi lymphocytes exhibited increased effector phenotype acquisition,augmented proliferation,and an inverted CD4/CD8 ratio in both oxygen conditions. Moreover,Glut1-Hi T lymphocytes exhibited a significantly enhanced ability to produce IFN-γ and this secretion potential was completely dependent on continued glycolysis. Thus,Glut1 surface levels identify human T lymphocytes with distinct effector functions in both hypoxic and atmospheric oxygen tensions. View Publication

CD8(+) T cells have a central role in antitumour immunity,but their activity is suppressed in the tumour microenvironment. Reactivating the cytotoxicity of CD8(+) T cells is of great clinical interest in cancer immunotherapy. Here we report a new mechanism by which the antitumour response of mouse CD8(+) T cells can be potentiated by modulating cholesterol metabolism. Inhibiting cholesterol esterification in T cells by genetic ablation or pharmacological inhibition of ACAT1,a key cholesterol esterification enzyme,led to potentiated effector function and enhanced proliferation of CD8(+) but not CD4(+) T cells. This is due to the increase in the plasma membrane cholesterol level of CD8(+) T cells,which causes enhanced T-cell receptor clustering and signalling as well as more efficient formation of the immunological synapse. ACAT1-deficient CD8(+) T cells were better than wild-type CD8(+) T cells at controlling melanoma growth and metastasis in mice. We used the ACAT inhibitor avasimibe,which was previously tested in clinical trials for treating atherosclerosis and showed a good human safety profile,to treat melanoma in mice and observed a good antitumour effect. A combined therapy of avasimibe plus an anti-PD-1 antibody showed better efficacy than monotherapies in controlling tumour progression. ACAT1,an established target for atherosclerosis,is therefore also a potential target for cancer immunotherapy. View Publication

Langerhans cells (LC) are a unique subset of dendritic cells (DC),present in the epidermis and serving as the first line of defense against pathogens invading the skin. To investigate the role of human LCs in innate immune responses,we examined TLR expression and function of LC-like DCs derived from CD34+ progenitor cells and compared them to DCs derived from peripheral blood monocytes (monocyte-derived DC; Mo-DC). LC-like DCs and Mo-DCs expressed TLR1-10 mRNAs at comparable levels. Although many of the TLR-induced cytokine patterns were similar between the two cell types,stimulation with the TLR3 agonist poly(I:C) triggered significantly higher amounts of the IFN-inducible chemokines CXCL9 (monokine induced by IFN-gamma) and CXCL11 (IFN-gamma-inducible T cell alpha chemoattractant) in LC-like DCs as compared with Mo-DCs. Supernatants from TLR3-activated LC-like DCs reduced intracellular replication of vesicular stomatitis virus in a type I IFN-dependent manner. Finally,CXCL9 colocalized with LCs in skin biopsy specimens from viral infections. Together,our data suggest that LCs exhibit a direct antiviral activity that is dependent on type I IFN as part of the innate immune system. View Publication

The presence of persistent,latent HIV reservoirs in CD4+ T cells obstructs current efforts to cure infection. The so-called kick-and-kill paradigm proposes to purge these reservoirs by combining latency-reversing agents with immune effectors such as cytotoxic T lymphocytes. Support for this approach is largely based on success in latency models,which do not fully reflect the makeup of latent reservoirs in individuals on long-term antiretroviral therapy (ART). Recent studies have shown that CD8+ T cells have the potential to recognize defective proviruses,which comprise the vast majority of all infected cells,and that the proviral landscape can be shaped over time due to in vivo clonal expansion of infected CD4+ T cells. Here,we have shown that treating CD4+ T cells from ART-treated individuals with combinations of potent latency-reversing agents and autologous CD8+ T cells consistently reduced cell-associated HIV DNA,but failed to deplete replication-competent virus. These CD8+ T cells recognized and potently eliminated CD4+ T cells that were newly infected with autologous reservoir virus,ruling out a role for both immune escape and CD8+ T cell dysfunction. Thus,our results suggest that cells harboring replication-competent HIV possess an inherent resistance to CD8+ T cells that may need to be addressed to cure infection. View Publication

Primary systemic amyloidosis (AL) is a rare monoclonal plasma cell (PC) disorder characterized by the deposition of misfolded immunoglobulin (Ig) light chains (LC) in vital organs throughout the body. To our knowledge,no cell lines have ever been established from AL patients. Here we describe the establishment of the ALMC-1 and ALMC-2 cell lines from an AL patient. Both cell lines exhibit a PC phenotype and display cytokine-dependent growth. Using a comprehensive genetic approach,we established the genetic relationship between the cell lines and the primary patient cells,and we were also able to identify new genetic changes accompanying tumor progression that may explain the natural history of this patient's disease. Importantly,we demonstrate that free lambda LC secreted by both cell lines contained a beta structure and formed amyloid fibrils. Despite absolute Ig LC variable gene sequence identity,the proteins show differences in amyloid formation kinetics that are abolished by the presence of Na(2)SO(4). The formation of amyloid fibrils from these naturally secreting human LC cell lines is unprecedented. Moreover,these cell lines will provide an invaluable tool to better understand AL,from the combined perspectives of amyloidogenic protein structure and amyloid formation,genetics,and cell biology. View Publication

Plant lectins displaying similar single sugar-binding specificity and identical molecular structure might present various biological effects. To explore this possibility,the effects on human lymphocytes of two mannose-specific and structurally closely related lectins,Morniga M from Morus nigra and artocarpin from Artocarpus integrifolia were investigated. In silico analysis revealed that Morniga M presents a more largely open carbohydrate-binding cavity than artocarpin,probably allowing interactions with a broader spectrum of carbohydrate moieties. In vitro,Morniga M interacted strongly with the lymphocyte surface and was uptaken quickly by cells. Morniga M and artocarpin triggered the proliferation and activation of human T and NK lymphocytes. A minority of B lymphocytes was activated in artocarpin-treated culture,whereas Morniga M favored the emergence of CD4+ CD8+ T lymphocytes. Moreover,cell death occurred in activated PBMC,activated T lymphocytes,and Jurkat T leukemia cells incubated with Morniga M only. The biological effects of both lectins were dependent on carbohydrate recognition. The Morniga M-induced cell death resulted,at least in part,from caspase-dependent apoptosis and FADD-dependent receptor-mediated cell death. Finally,Morniga M,but not artocarpin,triggered AICD of T lymphocytes. In conclusion,both lectins trigger lymphocyte activation,but only Morniga M induces cell death. In spite of similar in vitro mannose-binding specificities and virtually identical structure,only Morniga M probably interacts with carbohydrate moieties bound to molecules able to induce cell death. The present data suggest that subtle alterations in N-glycans can distinguish activation and cell death molecules at the lymphocyte surface. View Publication

New vaccines against pertussis are needed to evoke full protection and long-lasting immunological memory starting from the first administration in neonates--the major target of the life-threatening pertussis infection. A novel live attenuated Bordetella pertussis vaccine strain,BPZE1,has been developed by eliminating or detoxifying three important B. pertussis virulence factors: pertussis toxin,dermonecrotic toxin,and tracheal cytotoxin. We used a human preclinical ex vivo model based on monocyte-derived dendritic cells (MDDCs) to evaluate BPZE1 immunogenicity. We studied the effects of BPZE1 on MDDC functions,focusing on the impact of Bordetella-primed dendritic cells in the regulation of Th and suppressor T cells (Ts). BPZE1 is able to activate human MDDCs and to promote the production of a broad spectrum of proinflammatory and regulatory cytokines. Moreover,conversely to its parental wild-type counterpart BPSM,BPZE1-primed MDDCs very efficiently migrate in vitro in response to the lymphatic chemokine CCL21,due to the inactivation of pertussis toxin enzymatic activity. BPZE1-primed MDDCs drove a mixed Th1/Th17 polarization and also induced functional Ts. Experiments performed in a Transwell system showed that cell contact rather than the production of soluble factors was required for suppression activity. Overall,our findings support the potential of BPZE1 as a novel live attenuated pertussis vaccine,as BPZE1-challenged dendritic cells might migrate from the site of infection to the lymph nodes,prime Th cells,mount an adaptive immune response,and orchestrate Th1/Th17 and Ts responses. View Publication

The effector potential of NK cells is counterbalanced by their sensitivity to inhibition by self" MHC class I molecules in a process called "education." In humans� View Publication