bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fcε Receptor I-Associatedlyn-Dependent Phosphorylation of Fcγ Receptor IIB During Negative Regulation of Mast Cell Activation
Authors: Malbec Odile , Fong Dana C. , Turner Martin , Tybulewicz Victor L. J. , Cambier John C. , Fridman Wolf H. , Daëron Marc 
Published: December 2022

AbstractFcγRIIB are low-affinity receptors for IgG whose intracytoplasmic domain contains an immunoreceptor tyrosine-based inhibition motif (ITIM). FcγRIIB inhibit cell activation triggered by receptors that signal via immunoreceptor tyrosine-based activation motifs. This inhibition requires ITIM tyrosyl phosphorylation and is correlated with the binding of SH2 domain-containing phosphatases that may mediate the inhibitory signal. In the present work, we investigated the mechanism of FcγRIIB phosphorylation and its consequences in mast cells. We demonstrate that the phosphorylation of FcγRIIB requires coaggregation with FcεRI and that, once phosphorylated, FcγRIIB selectively recruit the inositol polyphosphate 5 phosphatase SHIP, in vivo. In vitro, however, the phosphorylated FcγRIIB ITIM binds not only SHIP, but also the two protein tyrosine phosphatases, SHP-1 and SHP-2. We show that the coaggregation of FcγRIIB with FcεRI does not prevent FcεRI-mediated activation of lyn and syk. Both kinases can phosphorylate FcγRIIB in vitro. However, when coaggregated with FcεRI, FcγRIIB was in vivo phosphorylated in syk-deficient mast cells, but not in lyn-deficient mast cells. When FcεRI are coaggregated with FcγRIIB by immune complexes, FcεRI-associated lyn may thus phosphorylate FcγRIIB. By this mechanism, FcεRI initiate ITIM-dependent inhibition of intracellular propagation of their own signals.
Bispecific Molecules Directed to the Fc Receptor for IgA (FcαRI, CD89) and Tumor Antigens Efficiently Promote Cell-Mediated Cytotoxicity of Tumor Targets in Whole Blood
Authors: Deo Yashwant M. , Sundarapandiyan Karuna , Keler Tibor , Wallace Paul K. , Graziano Robert F. 
Published: December 2022

AbstractThe FcR for IgA (FcαRI, CD89) is primarily expressed on cytotoxic immune effector cells. By chemically cross-linking F(ab′) fragments of the FcR for IgA (FcαRI)-specific mAb (A77) with tumor Ag-specific mAb (anti-HER2/neu and anti-epidermal growth factor receptor), we have developed bispecific molecules (BSM) that simultaneously bind to respective tumor Ags and FcαRI-expressing effector cells in whole blood. These BSM mediated up to 55% of specific lysis of appropriate tumor Ag-expressing target cells (from a variety of tumors) with purified polymorphonuclear leukocytes, monocytes, or whole blood effector cells without preactivation with exogenous cytokines. To our knowledge, this is the first demonstration of Ab-dependent cell-mediated cytotoxic activity via FcαRI in whole blood. Also, monocyte-derived macrophages mediated phagocytosis of HER2/neu-expressing tumor cells (&gt;95% tumor cell loss). These BSM-mediated cytotoxic activities were completely inhibited by F(ab′)2 of A77, demonstrating the specific role of FcαRI as a trigger molecule. Furthermore, the binding of these BSM to monocytes or polymorphonuclear leukocytes in whole blood did not induce modulation of FcαRI in the absence of the target Ag. Therefore, immune effector cells may be “armed” with FcαRI-directed BSM in whole blood. These FcαRI-directed BSM may offer new treatment options for various malignancies and other disease conditions.
Antigen-Primed T Cells from B Cell-Deficient JHD Mice Fail to Provide B Cell Help
Authors: Macaulay Anne E. , DeKruyff Rosemarie H. , Umetsu Dale T. 
Published: December 2022

AbstractB cells are effective in presenting Ag to primed T cells, but a specific role for B cells in priming naive T cells has not been clearly established. In this report we demonstrate that Ag administration to B cell-deficient JHD mice primes T cells for Ag-specific proliferative responses, but such primed T cells fail to provide help for isotype switching and IgG production in B cells. Although T cells primed in the absence of B cells could proliferate in response to Ag presented by B cells and could induce Ag-specific IgM production, such T cells failed to produce high levels of IL-4 as are normally induced in T cells by Ag-presenting B cells. These findings suggest that while B cells are not absolutely required for T cell priming, they provide signals to T cells that are not replicated by other APCs and that influence the subsequent ability of T cells to interact with B cells.
CD40 Ligand/CD40 Stimulation Regulates the Production of IFN-γ from Human Peripheral Blood Mononuclear Cells in an IL-12- and/or CD28-Dependent Manner
Authors: McDyer John F. , Goletz Theresa J. , Thomas Elaine , June Carl H. , Seder Robert A. 
Published: December 2022

AbstractCD40 ligand (CD40L)/CD40 costimulation is an important regulator of Th1 responses. Two mechanisms by which CD40L/CD40 stimulation may enhance IFN-γ are via direct induction of IL-12 and augmentation of the expression of costimulatory molecules such as B7 from APCs. We examined the ability of CD40L/CD40 stimulation to regulate the production of IFN-γ through IL-12 and/or CD28 costimulation from human PBMCs stimulated with T cell-specific stimuli. The roles of exogenous and endogenous CD40L/CD40 stimulation were evaluated using a trimeric soluble CD40L agonist (CD40T) and an anti-CD40L Ab, respectively. The presence of CD40T in cultures increased the production of IL-12 and IFN-γ from PBMCs stimulated with varying amounts of PHA. The mechanism, however, by which CD40T enhanced IFN-γ varied according to the level of T cell activation. Under maximal stimulatory conditions (PHA, 1/100), an IL-12-dependent pathway was dominant. At relatively low levels of T cell stimulation (PHA, 1/500 and 1/1000), however, an additional IL-12-independent CD28-dependent pathway was elucidated. We further studied the role of exogenous CD28 stimulation in regulating the production of IFN-γ. The enhancement of IFN-γ production induced by direct CD28 stimulation was primarily dependent on endogenous IL-12 or CD40L/CD40 stimulation. Together, these data suggest that the production of IFN-γ involves a complex interaction between two interdependent, yet distinct, costimulatory pathways and provide evidence that CD40T may be an effective adjuvant for the enhancement of responses.
Resistance to Polyoma Virus-Induced Tumors Correlates with CTL Recognition of an Immunodominant H-2Dk-Restricted Epitope in the Middle T Protein
Authors: Lukacher Aron E. , Wilson Christopher S. 
Published: December 2022

AbstractThe natural mouse pathogen polyoma virus is highly oncogenic in H-2k mice carrying the endogenous superantigen encoded by the mouse mammary tumor provirus Mtv-7. This superantigen results in deletion of Vβ6 TCR-expressing polyoma-specific CD8+ CTL, which appear to be critical effectors against polyoma tumorigenesis. Here we have isolated cloned lines of CD8+ T cells from resistant (i.e., Mtv-7−) H-2k mice that specifically lyse syngeneic polyoma virus-infected cells and polyoma tumor cells. Nearly all these CTL clones express Vβ6 and are restricted in their recognition of virus-infected cells by H-2Dk. Screening a panel of synthetic peptides predicted to bind to Dk, for which no consensus peptide binding motif is known, we identified a peptide corresponding to a nine-amino acid sequence in the carboxyl-terminus of the middle T (MT) protein (amino acids 389–397) that was recognized by all the Vβ6+CD8+ CTL clones. The inability of MT389–397-reactive CTL to recognize cells infected with a mutant polyoma virus encoding a MT truncated just proximal to this sequence indicates that MT389-397 is a naturally processed peptide. The frequencies of precursor CTL specific for polyoma virus and MT389–397 peptide were similar, indicating that MT389–397 is the immunodominant epitope in H-2k mice. In addition, polyoma-infected resistant mice possess a 10- to 20-fold higher MT389-397-specific precursor CTL frequency than susceptible mice. This highly focused CTL response to polyoma virus provides a valuable animal model to investigate the in vivo activity of CTL against virus-induced neoplasia.
Role of CD80 (B7.1) and CD86 (B7.2) in the Immune Response to an Intracellular Pathogen
Authors: Subauste Carlos S. , de Waal Malefyt Rene , Fuh Franklin 
Published: December 2022

AbstractThe costimulatory ligands CD80 and CD86 play a crucial role in the initiation and maintenance of an immune response. We demonstrate that whereas infection of human monocytes with viable tachyzoites of Toxoplasma gondii resulted in rapid induction of expression of CD80 and up-regulation of expression of CD86, incubation with killed organisms failed to alter the levels of expression of these costimulatory ligands. The T. gondii-mediated changes in levels of expression of these molecules are critical to the T cell response to the parasite. Proliferation of resting T cells in response to parasite-infected cells was dependent on both CD80 and CD86. More importantly, early production of IFN-γ in response to T. gondii by T cells from T. gondii-seronegative individuals occurred only after stimulation with monocytes that exhibited increased expression of CD80 and CD86 (monocytes infected with viable parasites) and was almost completely ablated by the combination of anti-CD80 plus anti-CD86 mAb. Moreover, proliferation and IFN-γ production by CD4+ CD45RA+ T cells from unexposed individuals were dependent on both CD80 and CD86. These data indicate that pathogen-monocyte interaction influences the ensuing T cell response.
Morphine Enhances Macrophage Apoptosis
Authors: Singhal Pravin C. , Sharma Puneet , Kapasi Aditi A. , Reddy Krishna , Franki Nicholas , Gibbons Nora 
Published: December 2022

AbstractLaboratory data indicate that morphine decreases the number of peritoneal and alveolar macrophages (Mφ) and compromises their phagocytic capability for immune complexes and bacteria. We hypothesize that morphine decreases the number of, as well as compromises the phagocytic capability of, Mφ by programming their death. We studied the effect of morphine on Mφ apoptosis in vivo as well as in vitro. Peritoneal Mφ harvested from morphine-treated rats showed DNA fragmentation. Morphine enhanced murine Mφ (J 774.16) apoptosis in a dose-dependent manner. Human monocytes treated with morphine showed a classic ladder pattern in gel electrophoretic and end-labeling studies. Morphine promoted nitric oxide (NO) production both under basal and LPS-activated states. NG-nitro-l-arginine methyl ester (l-NAME) and NG-monomethyl-l-arginine monoacetate (l-NMMA), inhibitors of NO synthase, attenuated the morphine-induced generation of NO by Mφ. Morphine also enhanced Mφ mRNA expression of inducible NO synthase (iNOS). Since morphine-induced Mφ apoptosis was inhibited by L-NAME and L-NMMA, it appears that morphine-induced Mφ apoptosis may be mediated through the generation of NO. Morphine promoted the synthesis of Bax and p53 proteins by Mφ. Moreover, IL-converting enzyme (ICE)-1 inhibitor attenuated morphine-induced Mφ apoptosis. These studies suggest that morphine activates the induction phase of the apoptotic pathway through accumulation of p53. The effector phase of morphine-induced apoptosis appears to proceed through the accumulation of Bax and activation of ICE-1. The present study provides a basis for a hypothesis that morphine may be directly compromising immune function by promoting Mφ apoptosis in patients with opiate addiction.
CD14-Dependent Internalization of Bacterial Lipopolysaccharide (LPS) Is Strongly Influenced by LPS Aggregation But Not by Cellular Responses to LPS
Authors: Kitchens Richard L. , Munford Robert S. 
Published: December 2022

AbstractWe analyzed the impact of ligand aggregation and LPS-induced signaling on CD14-dependent LPS internalization kinetics in human monocytic THP-1 cells and murine macrophages. Using two independent methods, we found that the initial rate and extent of LPS internalization increased with LPS aggregate size. In the presence of LPS binding protein (LBP), large LPS aggregates were internalized extremely rapidly (70% of the cell-associated LPS was internalized in 1 min). Smaller LPS aggregates were internalized more slowly than the larger aggregates, and LPS monomers, complexed with soluble CD14 in the absence of LBP, were internalized very slowly after binding to membrane CD14 (5% of the cell-associated LPS was internalized in 1 min). In contrast, the initial aggregation state had little or no effect on the stimulatory potency of the LPS. Previous studies suggest that LPS-induced signal responses may influence the intracellular traffic and processing of LPS. We found that elicited peritoneal macrophages from LPS-responsive (C3H/HeN) and LPS-hyporesponsive (C3H/HeJ) mice internalized LPS with similar kinetics. In addition, pre-exposure of THP-1 cells to LPS had no effect on their ability to internalize subsequently added LPS, and pre-exposure of the cells to the LPS-specific inhibitor, LA-14-PP, inhibited stimulation of the cells without inhibiting LPS internalization. In these cells, LPS is thus internalized by a constitutive cellular mechanism(s) with kinetics that depend importantly upon the physical state in which the LPS is presented to the cell.
Ox-40 Ligand: A Potent Costimulatory Molecule for Sustaining Primary CD4 T Cell Responses
Authors: Gramaglia Irene , Weinberg Andrew D. , Lemon Michael , Croft Michael 
Published: December 2022

AbstractOx-40 and Ox-40 ligand (Ox-40L) are thought to be involved in T cell-APC interactions. However, their exact role in T cell responses is undefined. Using fibroblast transfectants expressing Ox-40L and/or B7-1, and CD4 cells from TCR transgenic mice, we investigated the effect of Ox-40 signaling on primary responses to the Ag pigeon cytochrome c. Ox-40 expression on naive CD4 cells peaked 2 to 3 days after activation, and was lost by 4 to 5 days. APCs with Ox-40L promoted partial activation of naive T cells with some IL-2 secretion, but were unable to enhance proliferation, unlike those with B7-1. APCs coexpressing Ox-40L with B7-1 induced large quantities of IL-2 and promoted proliferative responses that persisted for several days. Effector cells taken 5 days after naive T cell activation reexpressed Ox-40 within 4 h and responded strongly to APCs expressing Ox-40L, whereas B7-1 had little effect. Synergy was also seen between Ox-40L and B7-1, with primarily IL-2 being elevated, although IL-4 and IL-5 were also up-regulated. The most striking action was on effector T cell proliferation, which continued at high levels for up to 4 days, with little proliferation evident at this time in the absence of Ox-40 signals. These data suggest that Ox-40/Ox-40L interactions act after initial activation events to prolong clonal expansion and enhance effector cytokine secretion, and may be involved in promoting long-lived primary CD4 responses.
Antagonistic Roles for Phospholipase D Activities in B Cell Signaling: While the Antigen Receptors Transduce Mitogenic Signals Via a Novel Phospholipase D Activity, Phosphatidylcholine-Phospholipase D Mediates Antiproliferative Signals
Authors: Gilbert Jonathan J. , Pettitt Trevor R. , Seatter Sandra D. , Reid Steven D. , Wakelam Michael J. O. , Harnett Margaret M. 
Published: December 2022

AbstractCross-linking of the Ag receptors on B cells induces DNA synthesis and proliferation. Butanol trap experiments suggest that one or more phospholipase D activities play a key role in this process. Although phosphatidylcholine-phospholipase D has been shown to play a central role in the transduction of proliferative responses for a wide variety of calcium-mobilizing receptors, we show that the Ag receptors are not coupled to this phospholipase. In addition, phosphatidylcholine-phospholipase D is not stimulated under conditions that mimic T cell-dependent B cell activation. In contrast, ATP, which inhibits surface Ig (sIg)-mediated DNA synthesis in murine B cells via P2-purinoceptors, activates phosphatidylcholine-phospholipase D. Phosphatidylcholine-phospholipase D is therefore associated with antiproliferative signal transduction in mature B cells, but it does not transduce early signals associated with sIg-mediated growth arrest or apoptosis in immature B cells. Mitogenic stimulation of sIg is, however, coupled to a novel nonphosphatidylcholine-hydrolyzing phospholipase D activity. The resultant sIg-generated phosphatidic acid, unlike the phosphatidylcholine-derived phosphatidic acid generated via the purinoceptors, is converted to diacylglycerol. These data provide the first evidence that while the novel sIg-coupled phospholipase D and resultant diacylglycerol generation may play a role in B cell survival and proliferation, phosphatidylcholine-phospholipase D may transduce, via phosphatidic acid, negative immunomodulatory signals in mature B lymphocytes.
Induction or Protection from Experimental Autoimmune Encephalomyelitis Depends on the Cytokine Secretion Profile of TCR Peptide-Specific Regulatory CD4 T Cells
Authors: Kumar Vipin , Sercarz Eli 
Published: December 2022

AbstractAutoimmune diseases can result from the breakdown of regulation and subsequent activation of self-antigenic determinant-reactive T cells. During the evolution of the autoimmune response to myelin basic protein (MBP) in B10.PL mice, several distinct T cell populations expand: the effectors mediating experimental autoimmune encephalomyelitis (EAE) are MBP-reactive, CD4+, and predominantly TCR Vβ8.2+; in addition, at least two regulatory populations can be detected—one comprised of Vβ14+ CD4 T cells, reactive to a framework region 3 determinant on the Vβ8.2 chain, and a second that is CD8+ and reactive to another Vβ8.2 determinant. The combined action of these two regulatory cell types controls disease-causing effectors, resulting in spontaneous recovery from disease. In this report, we reveal that the cytokine secretion pattern of TCR peptide-specific regulatory CD4 T cells can profoundly influence whether a type 1 or type 2 population predominates among MBP-specific CD4 effectors. The priming of type 1 regulatory T cells results in deviation of the Ag-specific effector T cell population in a type 2 direction and protection from disease. In contrast, induction of type 2 regulatory T cells results in exacerbation of EAE, poor recovery, and an increased frequency of type 1 effectors. Thus, the encephalitogenic potential of the MBP-reactive effector population is crucially and dominantly influenced by the cytokine secretion phenotype of regulatory CD4 T cells. These findings have important implications in understanding peripheral tolerance to self-Ags as well as in the design of TCR-based therapeutic approaches.
Clonal Expansion Within CD4+ and CD8+ T Cell Subsets in Human T Lymphotropic Virus Type I-Infected Individuals
Authors: Eiraku Nobutaka , Hingorani Ravi , Ijichi Shinji , Machigashira Koichi , Gregersen Peter K. , Monteiro Joanita , Usuku Koichiro , Yashiki Shinji , Sonoda Shunro , Osame Mitsuhiro , Hall William W. 
Published: December 2022

AbstractTo investigate the diversity of the T cell repertoire involved in human T lymphotropic virus type I (HTLV-I) infections, peripheral blood T cell subsets were analyzed by using a PCR-based assay that permits determination of complementarity-determining region 3 (CDR3) length variation in TCR Vβ transcripts. In two of four asymptomatic HTLV-I carriers and in four of five patients with HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP), mono- or oligoclonal expansions were detected in the CD4+ T cell subset. In one patient with adult T cell leukemia, a specific clone bearing Vβ7 was detected in the CD4+ T cell subset. In contrast, clonal expansion was not observed in the CD4 T cell subsets of three individuals with asymptomatic HTLV-II infection or in our previous studies of a large number of uninfected individuals. Oligoclonal expansions in the CD8+ T cell subset were detected in all subjects, including the patient with adult T cell leukemia. No differences in the number of expanded clones were noted between asymptomatic carriers and in patients with HAM/TSP and there was no obvious restriction in the TCR V region usage. Direct sequencing revealed no significant bias in the CDR3 motifs utilized by the predominant clones. This report is the first direct demonstration of clonal expansions within fractionated T cell subsets (CD4+ and CD8+) in HTLV-I infections and suggests that 1) clonal expansion of CD4+ T lymphocytes likely occurs as a direct result of infection and 2) polyclonal CD8+ T cell expansion occurs frequently and independently of disease association.
Intrinsic Defects in Macrophage IL-12 Production Associated with Immune Dysfunction in the MRL/++ and New Zealand Black/White F1 Lupus-Prone Mice and theLeishmania major-Susceptible BALB/c Strain
Authors: Alleva David G. , Kaser Steven B. , Beller David I. 
Published: December 2022

AbstractWe have demonstrated that macrophages (Mφ) from young, prediseased, lupus-prone MRL/++ and New Zealand Black/White F1 mice display defective production of TNF-α, IL-1, and IL-6, but normal production of IL-10. In an attempt to determine the potential functional implications of this phenotype for autoimmunity, we demonstrate here that endotoxin-activated Mφ from these lupus-prone mice showed dramatically reduced expression of IL-12, a cytokine essential for Th1 responses that may be defective during lupus. IL-12 production was also reduced by Mφ from the control BALB/c strain, compatible with the concept that a genetically programmed deficit in IL-12 levels may underlie the IL-4-dominated BALB/c response to infection by the parasite Leishmania major. Although both IL-12 and TNF-α expression defects by Mφ from lupus-prone strains are expressed rapidly after activation, treatment with each cytokine demonstrated that only TNF-α contributes to the subsequent dysregulation of Mφ IL-1 and IL-6 expression in these strains, and that the reduced autocrine activity of defective IL-12 or TNF-α levels was not causal to each other. Although the intrinsic defect in IL-12 expression by lupus-prone and BALB/c Mφ may lead to defective Th1 responses, these Mφ responded to the Th1-derived cytokine, IFN-γ, in a normal fashion suggesting a defective role in the induction, rather than the propagation, of Th1 responses in these mice. Our finding of a conserved intrinsic defect in IL-12 production by Mφ from the two principal mouse models of multigenic lupus provides insight into how excessive humoral responses may develop, and perhaps be prevented, in systemic autoimmune disease.