Local chemotherapy is increasingly used, either in combination with surgery or as monotherapy, for management of ocular tumors. Yet many of the local chemotherapeutic agents used for ocular tumors are cytotoxic drugs that are frequently associated with toxicities in normal ocular tissues. Understanding and managing these side effects are important because they affect treatment tolerability, outcome and quality of vision.
View Article and Find Full Text PDFResolution of inflammation is an active process that leads to tissue homeostasis and involves multiple cellular and molecular mechanisms. Myeloid-derived suppressor cells (MDSCs) have recently emerged as important cellular components in the resolution of inflammation because of their activities to suppress T cell activation. In this article, we show that HLA-DRCD11bCD33CD14 human MDSCs and CD11bLy6GLy6C mouse MDSCs markedly increased in patients and mice during and before the resolution phase of autoimmune uveoretinitis.
View Article and Find Full Text PDFMesenchymal stromal cells (MSCs) have therapeutic potential for various diseases because of their anti-inflammatory and immunosuppressive properties. However, the immunosuppressive microenvironment allows tumor cells to evade immune surveillance, whereas maintenance of inflammation is required for tumor development and progression. Hence, MSCs may promote or suppress tumors in a context-dependent manner.
View Article and Find Full Text PDFSelection and maturation of B cells into plasma cells producing high-affinity antibodies occur in germinal centers (GC). GCs form transiently in secondary lymphoid organs upon antigen challenge, and the GC reaction is a highly regulated process. TGF-β is a potent negative regulator, but the influence of other family members including bone morphogenetic proteins (BMPs) is less known.
View Article and Find Full Text PDFExcessive and prolonged activation of macrophages underlies many inflammatory and autoimmune diseases. To regulate activation and maintain homeostasis, macrophages have multiple intrinsic mechanisms, one of which is modulation through autophagy. Here we demonstrate that autophagy induction by rapamycin suppressed the production of IL-1β and IL-18 in lipopolysaccharide- and adenosine triphosphate-activated macrophages at the post-transcriptional level by eliminating mitochondrial ROS (mtROS) and pro-IL1β in a p62/SQSTM1-dependent manner.
View Article and Find Full Text PDFHypoxia and infiltration of tumor-associated macrophages (TAM) are intrinsic features of the tumor microenvironment. Tumor cells that remain viable in hypoxic conditions often possess an increased survival potential and tend to grow aggressively. TAM also respond to a variety of signals in the hypoxic tumor microenvironment and express a more M2-like phenotype.
View Article and Find Full Text PDFIntravenously administered mesenchymal stem/stromal cells (MSCs) engraft only transiently in recipients, but confer long-term therapeutic benefits in patients with immune disorders. This suggests that MSCs induce immune tolerance by long-lasting effects on the recipient immune regulatory system. Here, we demonstrate that i.
View Article and Find Full Text PDFExogenously administered mesenchymal stem/stromal cells (MSCs) suppress autoimmunity despite transient engraftment. However, the mechanism is unclear. In this study, we report a novel mechanism by which MSCs modulate the immune system by recruiting myeloid-derived suppressor cells in a mouse model of experimental autoimmune uveitis (EAU).
View Article and Find Full Text PDFActivating mutations in the NOTCH1 gene are found in over 50 % of T-ALL cases. Since Notch signaling contributes to the leukemia cell survival and growth, targeting Notch signaling using γ-secretase inhibitors (GSI) has been proposed as a molecularly targeted therapy for the treatment of T-ALL. However, not all T-ALL with NOTCH1 activating mutations respond to GSI treatment.
View Article and Find Full Text PDFThe germinal center (GC) is a dynamic microenvironment where antigen (Ag)-activated B cells rapidly expand and differentiate, generating plasma cells (PC) that produce high-affinity antibodies. Precise regulation of survival and proliferation of Ag-activated B cells within the GC is crucial for humoral immune responses. The follicular dendritic cells (FDC) are the specialized stromal cells in the GC that prevent apoptosis of GC-B cells.
View Article and Find Full Text PDFGamma secretase inhibitors (GSI), cell-permeable small-molecule inhibitors of gamma secretase activity, had been originally developed for the treatment of Alzheimer disease. In recent years, it has been exploited in cancer research to inhibit Notch signaling that is aberrantly activated in various cancers. We previously found that GSI could synergize with anti-microtubule agent, vincristine (VCR) in a Notch-independent manner.
View Article and Find Full Text PDFBiochem Biophys Res Commun
February 2013
The germinal center (GC) is the dynamic microenvironment where Ag-activated B cells rapidly expand and differentiate, generating plasma cells (PC) that produce high affinity antibodies. B cells within the GC have great heterogeneity, containing B cells at different stages of activation and differentiation. However, there are few surface markers that allow subsets of GC-B cells to be distinguished.
View Article and Find Full Text PDFFollicular dendritic cells (FDC) are an important subset of stromal cells within the germinal centres of lymphoid tissues. They are specialized to trap and retain antigen-containing immune complexes on their surfaces to promote B-cell maturation and immunoglobulin isotype class-switching. However, little is known of the cell types from which FDC originate.
View Article and Find Full Text PDFHistological transformation, a pivotal event in the natural history of cancers including lymphomas, is typically associated with more aggressive clinical behavior. L3055, a B lymphoma cell line of germinal center (GC) origin, is dependent on follicular dendritic cells (FDCs) for survival and proliferation, similar to GC-B cells. However, L3055 cells become less FDC-dependent after prolonged culture, which is analogous to transformation in vivo.
View Article and Find Full Text PDFThe GC is the anatomical site where antigen-activated B cells differentiate into PC, producing high-affinity antibodies in physiological and pathological states. PC differentiation is regulated by multiple factors within the GC microenvironment, including cytokines. IL-21, a recently identified type I cytokine produced by GC-Th cells, promotes differentiation of human B cells into ISC.
View Article and Find Full Text PDFThe Notch signaling pathway is one of the most conserved mechanisms to regulate cell fate in many tissues during development and postnatal life. In the immune system, Notch signaling regulates T and B cell development and modulates the differentiation of T and B cells. In this study, we investigated the functional roles of Notch signaling in human B cell differentiation within the germinal center (GC).
View Article and Find Full Text PDFCD320 has been recently discovered and reported as a follicular dendritic cell (FDC) protein. Although CD320 is known to enhance proliferation of germinal center (GC) B cells, little other information is available. In this study, we investigated its cellular distribution in the GC.
View Article and Find Full Text PDFIn a previous study we generated an anti-Hepatitis B Virus (HBV) preS1 humanized antibody (HzKR127) that showed in vivo HBV-neutralizing activity in chimpanzees. However, the antigen-binding affinity of the humanized antibody may not be sufficient for clinical use and thus affinity maturation is required for better therapeutic efficacy. In this study, phage display technique was employed to increase the affinity of HzKR127.
View Article and Find Full Text PDFThe tumor-associated glycoprotein (TAG)-72 is expressed in the majority of human adenocarcinomas but is rarely expressed in most normal tissues, which makes it a potential target for the diagnosis and therapy of a variety of human cancers. Here we describe the construction, affinity maturation, and biological characterization of an anti-TAG-72 humanized antibody with minimum potential immunogenicity. The humanized antibody was constructed by grafting only the specificity-determining residues (SDRs) within the complementarity-determining regions (CDRs) onto homologous human immunoglobulin germ line segments while retaining two mouse heavy chain framework residues that support the conformation of the CDRs.
View Article and Find Full Text PDFB cell-activating factor of the tumor necrosis factor family (BAFF/BLys) plays a critical role in B cell survival and immune responses through its three receptors: BAFF receptor (BAFF-R/BR3), transmembrane activator and calcium modulator and cyclophilin ligand interactor (TACI) and B cell maturation antigen (BCMA). Using specific antibodies, we have investigated the expression of BAFF-R on human tonsillar B cells and their functional roles in naive and germinal center (GC) B cell differentiation. Our studies show that BAFF-R is the dominant receptor on naive B cells.
View Article and Find Full Text PDFFactors that control the survival and proliferation of Ag-stimulated B cells within the germinal center (GC) are crucial for humoral immune responses with high affinity Abs against infectious agents. The follicular dendritic cell (FDC) is known as a key cellular component of the GC microenvironment for GC-B cell survival and proliferation. In this study, we report that IL-15 is produced by human FDC in vivo and by an FDC cell line, FDC/HK cells, in vitro.
View Article and Find Full Text PDFThe lymphoid follicle is a specialized microenvironment for the differentiation of antigen (Ag)-activated B cells; the major stromal cell components in lymphoid follicle are the follicular dendritic cells (FDCs). At the same time, most of the B-cell lymphomas originate from the germinal center, and the generation and blast transformation of B-cell lymphoma occurs in close association with FDCs in the early stage of tumorigenesis. To study the functional roles of FDCs in lymphomagenesis, we established an inducible tumor model.
View Article and Find Full Text PDFFour human monoclonal antibodies (MAbs) to hepatitis A virus (HAV) were isolated from a phage-displayed antibody library constructed from the peripheral blood lymphocytes (PBLs) of HAV-immune donors. The four MAbs showed differences in their affinity: two (HA6, HA9) of them were dominant after four rounds of panning, and showed higher affinity than the other two (HA1, HA12). All four MAbs showed HAV-neutralizing activity in radioimmunofocus inhibition assay and their neutralizing activity was positively correlated with their affinities.
View Article and Find Full Text PDFPreviously, a murine monoclonal antibody (mAb) KR127 (IgG2a/kappa) that binds specifically to the preS1 of hepatitis B virus (HBV) was generated and the fine epitope was mapped to amino acids (aa) 37-45 (NSNNPDWDF). In this current study, the epitope in combination with KR127 was tested for protein tagging. Initially, to evaluate the importance of each residue of the KR127 epitope in antibody binding, alanine substitution mutants of the epitope were constructed and characterized for KR127 binding by immunoblot analysis and competition ELISA.
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