Search results for "Immunomagnetic Separation"
showing 10 items of 15 documents
Development of an RNA-based kit for easy generation of TCR-engineered lymphocytes to control T-cell assay performance.
2018
Cell-based assays to monitor antigen-specific T-cell responses are characterized by their high complexity and should be conducted under controlled conditions to lower multiple possible sources of assay variation. However, the lack of standard reagents makes it difficult to directly compare results generated in one lab over time and across institutions. Therefore TCR-engineered reference samples (TERS) that contain a defined number of antigen-specific T cells and continuously deliver stable results are urgently needed. We successfully established a simple and robust TERS technology that constitutes a useful tool to overcome this issue for commonly used T-cell immuno-assays. To enable users t…
Cytomegalovirus Misleads Its Host by Priming of CD8 T Cells Specific for an Epitope Not Presented in Infected Tissues
2003
Cytomegaloviruses (CMVs) code for several proteins that inhibit the presentation of antigenic peptides to CD8 T cells. Although the molecular mechanisms of CMV interference with the major histocompatibility complex class I pathway are long understood, surprisingly little evidence exists to support a role in vivo. Here we document the first example of the presentation of an antigenic peptide being blocked by a CMV immune evasion protein in organs relevant to CMV disease. Although this Db-restricted peptide, which is derived from the antiapoptotic protein M45 of murine CMV (mCMV), is classified as an immunodominant peptide based on response magnitude and long-term memory, adoptive transfer of…
Depletion of naive T cells using clinical grade magnetic CD45RA beads: a new approach for GVHD prophylaxis
2013
Depletion of naive T cells from donor leukapheresis products (LPs) aims at the reduction of alloreactivity, while preserving memory T-cell reactivity (for example, to pathogens). This study established the immunomagnetic depletion procedure under clean room conditions using CD45RA beads and analyzed LPs of six donors for cell composition and functional immune responses. CD45RA depletion resulted in 3.4-4.7 log (median 4.4) reduction of CD45RA(+) T cells, thereby eliminating naive and late effector T cells. B cells were also completely removed, whereas significant proportions of NK cells, monocytes and granulocytes persisted. CD45RA-depleted LPs contained effector and central memory CD4(+) a…
Prophylactic transfer of CD8-depleted donor lymphocytes after T-cell–depleted reduced-intensity transplantation
2006
AbstractAllogeneic hematopoietic stem cell transplantation (SCT) regimens incorporating the lymphocytotoxic CD52 antibody alemtuzumab demonstrate efficient engraftment and reduced graft-versus-host disease (GVHD). However, these protocols substantially impair posttransplantation antiviral and antitumor immunity. To accelerate immune reconstitution after alemtuzumab-based reduced-intensity SCT, we administered prophylactic CD8-depleted donor lymphocyte infusions (DLIs) starting on days 60 and 120 after transplantation. DLIs were processed in an immunomagnetic good manufacturing practice depletion procedure resulting in a 2.5- to 6-log reduction in CD8 T cells. Of 23 high-risk patients with h…
Binding of monocytes from normolipidemic hyperglycemic patients with type 1 diabetes to endothelial cells is increased in vitro.
2009
Increased endothelial binding and emigration of monocytes play a dominant role in the pathogenesis of atherosclerosis in diabetes mellitus. Previous studies revealed that hyperlipidemia correlates with monocyte binding in vitro. The aim of this study was to characterize the monocyte-endothelial interaction of leucocytes of hyperglycemic patients with type 1 diabetes but lacking hyperlipidemia. We isolated monocytes from healthy controls and normolipidemic type 1 diabetes patients with elevated levels of HbA1c and quantified monocyte binding by an immunoilluminometric cell adhesion assay. Purity of isolated monocytes was at least 98%. Endothelial binding of monocytes from patients with type …
Immunelectronmicroscopic characterization of T4 and T8 lymphocytes and natural killer cells in neuronal ceroid-lipofuscinosis.
1995
CD4+, CD8+, and CD56+ cells were isolated with the immunomagnetic separation technique from peripheral blood mononuclear cells (PBMC) of 3 patients with neuronal ceroid-lipofuscinosis : one patient each with infantile (INCL), late infantile (LINCL), and juvenile (JNCL) neuronal ceroid-lipofuscinoses, all studied by light (LM) and electron (EM) microscopy. To compare the pathology of these cells with affected cells in other types of lysosomal diseases, the separation was also performed with PBMC of 1 patient with mucolipidosis (ML) type II, 2 patients with mucopolysaccharidosis (MPS) type I, and 4 patients with MPS type III. Disease-specific lysosomal inclusions were identified in CD4+, CD8+…
Rapid identification and sorting of viable virus-reactive CD4+ and CD8+ T cells based on antigen-triggered CD137 expression
2008
Abstract Current methods for the detection and isolation of antigen-specific CD4 + and CD8 + T cells require the availability of peptide/MHC multimers or are restricted to cells that produce cytokines after antigen contact. Here we show that de novo cell surface expression of the TNF-receptor family member CD137 (4-1BB) identifies recently activated, but not resting, human CD4 + and CD8 + memory T cells. Maximum CD137 expression level is uniformly observed in both T-cell subsets at 24h after stimulation with antigen. In experiments with CMV and EBV-reactive T cells, we confirmed the specificity of CD137 expression by co-staining with peptide/HLA tetramers. Substantial proportions of CD137 +…
Targeting the activation-induced antigen CD137 can selectively deplete alloreactive T cells from antileukemic and antitumor donor T-cell lines.
2006
AbstractIn HLA-incompatible hematopoietic stem cell transplantation, alloreactive donor T cells recognizing recipient mismatch HLA cause severe graft-versus-host disease (GVHD). Strategies allowing the selective depletion of alloreactive T cells as well as the enhancement of graft-versus-malignancy immunity would be beneficial. We generated donor CD8 T-cell lines in vitro using allogeneic recipient cells mismatched at a single HLA class I allele or haplotype as stimulators. Recipient cells were obtained from acute myeloid leukemias, renal-cell carcinomas, and CD40L-induced B lymphoblasts. Resulting alloreactive T cells were activated by incubating day 21 T-cell cultures with HLA-mismatch tr…
Adoptive transfer of protective immunity from Cryptosporidium parvum-infected interferon-gamma and interleukin-12-deficient mice to naive recipients.
2008
We investigated the possibility of transfer immunity from Cryptosporidium parvum-infected interferon-gamma (GKO) and interleukin-12p40 (IL-12KO) deficient C57BL/6 mice to naive mice by transfer of intraepithelial lymphocytes (IELs) and CD4(+) T cells from spleen and mesenteric lymph nodes (MLNs). Three days after the transfer recipients were infected with C. parvum. IELs isolated from GKO donor mice after resolution of infection (day 15) but not at the peak of infection (day 8) significantly reduced the parasite load in recipient mice. In IL-12KO mice, IELs and also CD4(+) T cells isolated from the spleen and MLNs of donor mice at the peak of infection (day 5) and after resolution (day 15) …
HBV viral load within subpopulations of peripheral blood mononuclear cells in HBV infection using limiting dilution PCR.
1999
Abstract Extrahepatic viral load in peripheral blood mononuclear cells (PBMCs) of patients with hepatitis B virus (HBV) is still under debate. In this study, HBV infection rates and viral titers were examined within all PBMC subpopulations using limiting dilution-PCR (LD-PCR). PBMCs of patients with acute or chronic hepatitis B were separated by magnetic beads in monocytes, B-cells, CD4+ T-cells, CD8+ T-cells, and NK cells. Using two-round nested PCR, HBV-DNA sequences were detected in all patients examined within each PBMC subpopulation. The frequencies of HBV-positive cells and viral loads were calculated by Poisson analysis of HBV PCR results from serial dilutions of cells and cell lysat…