32 research outputs found
Antigen Availability Determines CD8(+) T Cell-Dendritic Cell Interaction Kinetics and Memory Fate Decisions
No full textAbstract P5-01-06: Remodeling the tumor immune microenvironment via intratumoral administration of immunomodulatory agents
No full textGeneration of gut-homing IgA-secreting B cells by intestinal dendritic cells
No full textNormal intestinal mucosa contains abundant immunoglobulin A (IgA)-secreting cells, which are generated from B cells in gut-associated lymphoid tissues (GALT). We show that dendritic cells (DC) from GALT induce T cell-independent expression of IgA and gut-homing receptors on B cells. GALT-DC-derived retinoic acid (RA) alone conferred gut tropism but could not promote IgA secretion. However, RA potently synergized with GALT-DC-derived interleukin-6 (IL-6) or IL-5 to induce IgA secretion. Consequently, mice deficient in the RA precursor vitamin A lacked IgA-secreting cells in the small intestine. Thus, GALT-DC shape mucosal immunity by modulating B cell migration and effector activity through synergistically acting mediators
Abstract P4-06-02: Chemoimmunotherapy with cyclophosphamide plus a toll-like receptor 9 (TLR9) agonist eradicates triple negative breast cancer in a murine model
No full textUsing the R Package crlmm for Genotyping and Copy Number Estimation
No full textGenotyping platforms such as Affymetrix can be used to assess genotype-phenotype as well as copy number-phenotype associations at millions of markers. While genotyping algorithms are largely concordant when assessed on HapMap samples, tools to assess copy number changes are more variable and often discordant. One explanation for the discordance is that copy number estimates are susceptible to systematic differences between groups of samples that were processed at different times or by different labs. Analysis algorithms that do not adjust for batch effects are prone to spurious measures of association. The R package crlmm implements a multilevel model that adjusts for batch effects and provides allele-specific estimates of copy number. This paper illustrates a workflow for the estimation of allele-specific copy number and integration of the marker-level estimates with complimentary Bioconductor software for inferring regions of copy number gain or loss. All analyses are performed in the statistical environment R.
Can one written word mean many things? Prereaders’ assumptions about the stability of written words’ meanings
No full textResults of three experiments confirmed previous findings that in a moving word task, prereaders 3 to 5 years of age judge as if the meaning of a written word changes when it moves from a matching to a nonmatching toy (e.g., when the word “dog” moves from a dog to a boat). We explore under what circumstances children make such errors, we identify new conditions under which children were more likely correctly to treat written words’ meanings as stable: when the word was placed alongside a nonmatching toy without having been alongside a matching toy previously, when two words were moved from a matching toy to a nonmatching toy, and when children were asked to change what the print said. Under these conditions, children more frequently assumed that physical forms had stable meanings as they do with other forms of external representation
Intravital Multiphoton Microscopy Analysis of Spatial Relationships in Murine Skull Bone Marrow
No full textThe BM is a key organ of hematopoiesis and also has an important role in the immune system. The BM microenvironment is a complex, highly vascularized 3D structure composed of different cell types and extracellular matrix. Intense cellular traffic takes place from the peripheral blood to the BM and vice versa. However, the precise arrangement and microscopic dimensions of this environment have only been inferred so far from static imaging of sectioned tissue. We developed a new model to characterize and analyze the 3D microanatomy of murine skull BM in its physiological state using intravital MPM. This technology offers deep tissue penetration, low phototoxicity, superior image contrast and 3D resolution compared to other microscopy techniques. This makes MPM a powerful tool to investigate the BM, overcoming its anatomic inaccessibility. To quantify the dimensions of the BM compartment, we used high molecular weight FITC-dextran and Rhodamine 6G, which delineated the intra- and extravascular space, respectively. Measurements were generated using the 3D visualization and measurement software VoxBlast 3.1 after using a thresholding technique carried out by Adobe Photoshop 6.0. Results were expressed as the ratio of intravascular to extravascular space for different microvascular segments. Moreover, we performed adoptive transfer experiments with isolated naïve B-cells and TCM and studied their location within the BM compartment. The new approach presented here will be a useful tool for further in vivo investigations of cell behavior, trafficking and interactions in the BM
Killer cell immunoglobulin-like receptors and their ligands : assessment of potential diagnostic and immunotherapeutic value
No full textHuman natural killer (NK) cells constitute an important arm of the innate immune system, which participates in protection against viral infections and elimination of malignant diseases. They carry variegated receptors on their surface, with killer cell immunoglobulin-like receptors (KIR) playing a main role in the regulation of their activity. The KIR family involves inhibitory and activating members. The former interact with HLA class I molecules. Decreased or absent HLA class I expression abrogates inhibition. Binding specificities of activating members are mostly unknown (except for KIR2DS1 and KIR2DS4). However, there are abundant clinical data indirectly indicating a role for activating KIRs in antiviral and antileukemic NK cell activity.
Our studies aimed to dissect the role of activating KIRs in antiviral and antileukemic activity, and to assess their potential diagnostic and immunotherapeutic value. They were performed on the level of genotype associations, by evaluation of KIR repertoire after infectious challenge, and by assessing functionality in vitro.
In the first part, we searched for predictive markers allowing identification of HIV-infected patients able to control viral replication after structured treatment interruption (STI). Candidate factors were genes known to associate with HIV viral load in untreated patients. Therefore we studied the correlation of KIR3DL1 and its ligand HLA-Bw4, but also KIR3DS1 and SNPs (HLA-C-35 and HCP5) with the evolution of viral load after STI. Only the presence of HLA-Bw4 was significantly associated with control of viral replication. However, the predictive power of this genotype was modest.
In further studies we investigated differences of KIR expression in resting NK cells in CMV-seronegative and Ðseropositive individuals, and changes in KIR repertoire after challenging NK cells with CMV-infected fibroblasts in vitro. While resting NK cells did not differ in their KIR expression, in vitro exposure to CMV caused expansion of KIR2DL1, KIR2DL3, and KIR3DS1 uniquely in CMV seropositive donors. For KIR2DL1 and KIR2DL3, expansion occurred only in patients carrying the respective KIR ligands. The expansion of KIR3DS1 positive NK cells confirmed participation of the telomeric part of KIR haplotype B in anti-CMV activity, but was unrelated to presence of its putative ligand - HLA-Bw4.
These results encouraged us to broader studies of the function of activating KIRs. We therefore expressed a selected panel of activating KIRs separately in the NK cell line NKL, generated soluble forms of each activating KIR by connecting their extracellular domains to IgG-Fc fragments, and using these reagents to control specificity, we established a novel staining method for KIR2DS5 using commercially available antibodies. Despite functionality of expressed receptors against a mouse cell line, the presence of the KIR for which some HLA class I ligands are known did produce no detectable enhancement of cytotoxicity in cytotoxicity experiments against 721.221 cells transfected with these HLA class I ligands. Soluble forms of KIR-Fc were used to screen a panel of leukemic cell lines for the presence of potential KIR ligands by flow cytometry. The HLA class I deficient cell line K562 bound KIR2DS3-Fc and KIR2DS5-Fc, and the HLA class I expressing cell lines HEL and Namalwa bound also both these KIR-Fc on their surfaces. The binding of the latter was blockable by anti-HLA antibodies and - based on the HLA configuration of both cell lines - was independent on HLA-C. The participation of the KIR2DS5 receptor in killing of K562 cells by primary NK cells was indirectly confirmed, but requires a further investigation.
Collectively, these data suggest a potential antiviral effect of KIR3DS1 and a possible antileukemic effect of KIR2DS5. Their presence could predict individual immune responses, and taking into account their function could be beneficial in immunotherapeutic settings
Activation of natural killer cells during microbial infections.
No full textNatural killer (NK) cells are large granular lymphocytes that express a diverse array of germline encoded inhibitory and activating receptors for MHC Class I and Class I-like molecules, classical co-stimulatory ligands, and cytokines. The ability of NK cells to be very rapidly activated by inflammatory cytokines, to secrete effector cytokines, and to kill infected or stressed host cells, suggests that they may be among the very early responders during infection. Recent studies have also identified a small number of pathogen-derived ligands that can bind to NK cell surface receptors and directly induce their activation. Here we review recent studies that have begun to elucidate the various pathways by which viral, bacterial, and parasite pathogens activate NK cells. We also consider two emerging themes of NK cell-pathogen interactions, namely their contribution to adaptive immune responses and their potential to take on regulatory and immunomodulatory functions
T cell sensing of antigen dose governs interactive behavior with dendritic cells and sets a threshold for T cell activation
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