bluuebunny/crossref_metadata_2025_split huggingface dataset:
Increased sensitivity of gastric cancer cells to natural killer and lymphokine-activated killer cells by antisense suppression of N-acetylgalactosaminyltransferase.
Authors: Adachi T , Hinoda Y , Nishimori I , Adachi M , Imai K 
Published: December 2022

Abstract
UDP-N-acetylgalactosamine:polypeptide N-acetylgalactosaminyltransferases (GalNAc transferases) catalyze the initial reaction in O-linked (mucin type) oligosaccharide biosynthesis. To attempt to inhibit the synthesis of O-glycan, we transfected antisense cDNA of GalNAc transferase type 1 (GalNAc-T1) into a human gastric cancer cell line, JRST. A decreased expression of GalNAc-T1 at the level of both mRNA and protein was observed in the resultant transfectants. They demonstrated a significantly increased sensitivity to NK and lymphokine-activated killer cells in vitro compared with parental cells and mock transfectants. Although there was no significant difference in in vitro cell proliferation among parental cells, mock transfectants, or antisense transfectants, the in vivo growth rate of antisense transfectants using SCID mice was clearly lower than that of parental cells and mock transfectants. Furthermore, the treatment of mice with anti-asialo-G(M1) Ab abolished this growth-inhibitory effect of antisense transfection. From these results, we conclude that antisense suppression of GalNAc-T1 could increase the sensitivity of tumor cells to NK and lymphokine-activated killer cells, suggesting that this strategy may be of use as a new immunogene therapy.
Relationship between proliferation and susceptibility to CD95- and CD2-mediated apoptosis in stimulated primary T lymphocytes: T cells manifesting proliferative unresponsiveness are preferentially susceptible to CD95-mediated apoptosis.
Authors: Mollereau B , Blanchard D , Déas O , Dumont C , Métivier D , Bernard A , McGrew J T , Charpentier B , Vazquez A , Senik A 
Published: December 2022

Abstract
We examined the relationship between proliferation and susceptibility to Fas- and CD2-mediated apoptosis of human peripheral T lymphocytes that had been exposed in primary culture to CD3- or CD2-derived mitogenic stimuli in the presence of monocytes and exogenous IL-2. After 5 days, activated T cells were fractionated into large (F2) and small (F6) cells on Percoll density gradients and analyzed for their susceptibility to apoptosis and for their position in the cell cycle. Most F6 cells displayed a CD45RA+, CD25-, CD2R- phenotype and were unable to incorporate bromodeoxyuridine (BrdUrd) during the entire culture period. However, they were activated to express Fas Ag and some cell cycle regulatory proteins specific to late G1 phase. T cells with proliferative unresponsiveness were sensitive to Fas-mediated apoptosis whether it was triggered by anti-Fas mAb or by Fas ligand, but were almost completely resistant to CD2 apoptotic signaling. In contrast, F2 cells exhibited classical activation markers (CD45RO, CD25, and CD2R), had crossed S phase at least once, and were sensitive to both Fas and CD2 apoptotic signals. In large cells harvested earlier (on day 3), the signals were operative in both BrdUrd+ and BrdUrd- cells. Thus, S phase entry is not required for Fas- and CD2-mediated apoptosis. The profound proliferative unresponsiveness of F6 cells to CD3 and CD2 stimuli (bypassed by ionomycin plus PMA) and the CD2R- conformation of their CD2 molecules suggest that they may be in vivo anergized cells whose elimination, upon restimulation, is highly dependent on the Fas death pathway.
Transcription factor Egr-1 activity down-regulates Fas and CD23 expression in B cells.
Authors: Dinkel A , Aicher W K , Haas C , Zipfel P F , Peter H H , Eibel H 
Published: December 2022

Abstract
Activation of mature B cells via Ag receptor cross-linking induces transient expression of the transcription factor Egr-1. Although the activating signals leading to Egr-1 induction have been studied extensively, little is known about the genes that are placed further downstream within this activation cascade and that are transcriptionally regulated by Egr-1. To identify such target genes, we established Egr-1-overexpressing transfectants from the murine B cell line K46 and from human Ramos B cells. All clones derived from K46 B cells showed increased expression of CD44. Most interestingly, expression of CD95 (Fas/Apo-1) and of CD23 was down-regulated in all K46 transfectants. As a consequence, they became resistant to apoptosis induced by anti-CD95 Ab treatment. Similarly, the Egr-1-expressing Ramos cells showed reduced levels of CD95 expression. Thus, Egr-1 seems to control the expression of downstream target genes not only as a transcriptional activator, but also as a repressor molecule. In B cells, Egr-1 therefore plays a critical role in integrating the short-lived signal delivered by triggering of the Ag receptor into phenotypic changes, including repression of CD95 and CD23 transcription.
Phorbol myristate acetate stimulates the dimerization of CD44 involving a cysteine in the transmembrane domain.
Authors: Liu D , Sy M S 
Published: December 2022

Abstract
Receptor oligomerization is important for ligand binding and signal transduction. CD44 is a transmembrane protein present on many cell types. One of the ligands for CD44 is hyaluronic acid (HA). HA binding activity of CD44 is linked to cellular activation in some cell types. Clustering of CD44 has been speculated to be important for binding of HA. However, the molecular mechanisms for converting CD44 from an inactive receptor to an active receptor are not known. Here we report that PMA stimulates the binding of CD44 to HA by inducing clustering of CD44 followed by covalent homodimerization of CD44 on the cell surface. Covalent dimerization involves a cysteine (Cys286) in the transmembrane domain of CD44 and is essential for binding of high levels of fluorescein-conjugated HA. Activation-induced clustering followed by disulfide bond-mediated dimerization of CD44 represents an additional signal transduction mechanism for regulating receptor-ligand interactions.
Alternative peptide binding motifs of Qa-2 class Ib molecules define rules for binding of self and nonself peptides.
Authors: Tabaczewski P , Chiang E , Henson M , Stroynowski I 
Published: December 2022

Abstract
Studies of naturally processed peptides eluted from membrane-bound and soluble isoforms of murine class Ib Qa-2 molecules determined several features of these ligands, such as the conserved nonameric length and the preferred usage of specific residues at four to six of nine peptide positions. The structural information derived from these studies proved insufficient to distinguish between two interpretations: 1) that Qa-2 are peptide receptors of higher stringency than ordinary class I molecules, and 2) that Qa-2 molecules, like classical class I Ags, bind diverse arrays of peptides. We have addressed this issue by a systematic analysis of peptide residues involved in the binding of membrane-bound Qa-2 molecule, MQ9b. The optimal binding of synthetic peptides in vitro occurs at neutral pH. Two dominant anchors are required for peptide binding to MQ9b: His at position 7 and a hydrophobic residue, Leu, Ile, or Phe, at position 9. In addition, one or two auxiliary anchors participate in binding. The identity and the position of the auxiliary anchors differ from peptide to peptide, suggesting that the binding motifs defined from pool sequencing are composed of many superimposed alternative motifs present in individual peptides. The number of anchors used by Qa-2 peptides is similar to that found in ligands of classical class I Ags. Consequently, the Qa-2 are predicted to bind large repertoires of self and nonself peptides. In support of this interpretation we demonstrate that MQ9b binds strongly 5 of 17 motif-positive, pathogen-derived synthetic peptides.
MHC class Ib-restricted cells contribute to antilisterial immunity: evidence for Qa-1b as a key restricting element for Listeria-specific CTLs.
Authors: Bouwer H G , Seaman M S , Forman J , Hinrichs D J 
Published: December 2022

Abstract
Subclinical infection of BALB/c mice with the intracellular pathogen Listeria monocytogenes results in the development of MHC class Ia- and Ib-restricted CTLs. L. monocytogenes-infected TAP-/- bone marrow macrophage targets are not lysed by MHC class Ia- or Ib-restricted CTLs, showing a requirement for transport of peptides into the endoplasmic reticulum for development of the MHC class Ib-peptide target. L. monocytogenes-infected B6.Tla(a)-derived bone marrow macrophages (Kb Qa-1a) are not lysed by BALB/c (Kd Qa-1b)-derived antilisterial CTLs, confirming an earlier finding that the Ib-restricting element is T region encoded. We have further determined that Qa-1b is a restricting element for antilisterial CTLs using L. monocytogenes-infected Qa-1b-transformed mouse L cells as well as human-derived HeLa cells as target populations. These L. monocytogenes-infected Qa-1b-transformed cell lines are lysed by BALB/c (Qa-1b)- or C57BL/6 (Qa-1b)-derived antilisterial CTLs, but are not lysed by B6.AKM (Qa-1a)-derived antilisterial CTLs. Using L. monocytogenes-infected targets, we found that MHC class Ia- and Ib-restricted CTLs are evident within 4 days following infection, peak on day 5 following infection, and although Ib-restricted CTLs disappear by day 6 postinfection, la-restricted antilisterial CTL activity can still be detected. These results demonstrate that Qa-1b is a restricting element for antilisterial CTLs, and expression of the MHC class Ib-presented target at the cell surface is TAP dependent. In addition, these results show that following L. monocytogenes infection, MHC class Ib-restricted CTLs are evident in vivo.
CD28 expression by mouse mast cells is modulated by lipopolysaccharide and outer surface protein A lipoprotein from Borrelia burgdorferi.
Authors: Marietta E V , Weis J J , Weis J H 
Published: December 2022

Abstract
The concept of costimulation has been best defined in T cells and B cells. However, other cells that respond in an Ag-specific fashion, such as the mast cell, may be regulated by similar mechanisms. We have found that murine mast cells express one such costimulatory molecule, CD28, which was previously defined as a T and NK cell-specific protein. While CD28 transcription appeared to be constitutive in murine mast cells, its cell surface expression was not. CD28 cell surface expression by mast cells derived from bone marrow with stem cell factor (SCF) was dependent upon activation with agents such as LPS, the Borrelia burgdorferi lipoprotein outer surface protein A, and PMA. Peak cell surface expression of CD28 by such cells occurred 24 h after LPS stimulation, 18 h after outer surface protein A stimulation, and 3 h after PMA stimulation. In contrast, mast cells derived from bone marrow with IL-3 did not demonstrate induction-specific cell surface expression of CD28. Instead, maturation of such cells in vitro allowed for the increased cell surface expression of CD28. Peritoneal mast cells cultured in SCF also expressed CD28. Mast cell CD28 was functional, in that cross-linking of CD28 on the surface of the IL-3-derived cells resulted in an increased level of c-jun transcripts. Additionally, cross-linking of CD28 simultaneously with PMA treatment of SCF-derived mast cells resulted in an increased level of IL-13 transcripts. These data suggest that mast cell CD28 has functions similar to those of T cell CD28.
IL-10 improves lung injury and survival in Pseudomonas aeruginosa pneumonia.
Authors: Sawa T , Corry D B , Gropper M A , Ohara M , Kurahashi K , Wiener-Kronish J P 
Published: December 2022

Abstract
Pseudomonas aeruginosa is the most frequent Gram-negative pathogen causing nosocomial pneumonia. Four different strains of P. aeruginosa (including three isogenic transposon mutants) were utilized in experiments in mice to characterize the specific patterns of cytokine generation in response to bacterial products and cytotoxicity. Intratracheal instillation of any of the strains led to the up-regulation of IL-1beta, IL-6, and TNF-alpha mRNA. Instillation of the cytotoxic strains (PA103, PA103tox::omega) led to IL-10 mRNA up-regulation in the lungs and increased concentrations of IL-10 in the blood. In contrast, the instillation of the noncytotoxic strains (PA01, PA103exsA::omega) did not lead to an increase in IL-10 mRNA in the lungs or to an increase of IL-10 concentration in blood. IL-10 production appears to be a response to either cellular injury or to specific cytotoxic exoproducts produced by the bacteria. The systemic administration of rIL-10 significantly decreased the lung injury and the mortality in mice who had received the cytotoxic strains. The improvement in survival induced by administration of rIL-10 required the concomitant presence of IFN-gamma, as blockade of IFN-gamma with a neutralizing Ab led to 100% mortality, despite the administration of rIL-10. These results suggest that IL-10 is produced in response to specific bacterial products and that there is a potential role for IL-10 in the treatment of cytotoxic P. aeruginosa pneumonia.
Opsonized zymosan stimulates the redistribution of protein kinase C isoforms in human neutrophils.
Authors: Sergeant S , McPhail L C 
Published: December 2022

Abstract
We examined the ability of opsonized zymosan (OPZ) to stimulate translocation of protein kinase C (PKC) isoforms in human neutrophils. Neutrophils express five PKC isoforms (alpha, betaI, betaII, delta, and zeta), but little is known of their individual roles in neutrophil activation. As determined by immunoblotting, OPZ caused a time-dependent translocation of the predominant PKC isoforms (betaII, delta, and zeta) to neutrophil membranes, with a concomitant loss from the cytosol. Maximal translocation of all three isoforms occurred by 3 min. No PKC immunoreactivity was observed in a crude nuclear fraction, but PKC-delta and -zeta were found in the granule fraction after degranulation (10 min). PKC activity (Ca2+-dependent and -independent) increased 50- and 19-fold, respectively, by 10 min in the granules from OPZ-stimulated cells. Curiously, no immunoreactive cPKC (alpha and beta(I/II)) could be localized in the granule fraction to account for the Ca2+-dependent PKC activity. Localization of PKC isoforms in the neutrophil membranes and granules suggests their involvement in the regulation of functional responses triggered by OPZ. PKC isoform translocation to membranes from OPZ-stimulated cells preceded both p47phox (a cytosolic component of the NADPH oxidase) translocation and NADPH oxidase assembly. The presence of both PKC isoforms and p47phox in the membrane was transient, with the loss of p47phox occurring sooner than either the loss of membrane-associated PKC or that of NADPH oxidase activity. The apparent EC50 values for PKC translocation and NADPH oxidase assembly were similar. These data suggest that PKC isoforms regulate the assembly and activation of NADPH oxidase induced by OPZ.
Effect of recombinant human IL-4 on tryptase, chymase, and Fc epsilon receptor type I expression in recombinant human stem cell factor-dependent fetal liver-derived human mast cells.
Authors: Xia H Z , Du Z , Craig S , Klisch G , Noben-Trauth N , Kochan J P , Huff T H , Irani A M , Schwartz L B 
Published: December 2022

Abstract
The effect of recombinant human IL-4 (rhIL-4) on the development of recombinant human stem cell factor-dependent fetal liver-derived mast cells was examined. RhIL-4 attenuates the number of mast cells that develop, preferentially affecting the MC(T) type of mast cell. Cellular levels of tryptase and chymase mRNA normalized to that of glyceraldehyde-3-phosphate dehydrogenase were not appreciably affected. Tryptase mRNA levels peaked at least 2 wk before tryptase protein and before chymase mRNA and protein, indicating that tryptase mRNA expression is an early marker of commitment to a mast cell lineage. In contrast, alpha-tryptase and beta-tryptase mRNA levels increased and decreased in parallel. The most dramatic effect of rhIL-4 was to induce expression of functional surface Fc epsilonRI. Expression was maximal by 21 days with 20 ng/ml of rhIL-4 and reached a plateau by 2 ng/ml of rhIL-4 at 4 wk. Fc epsilonRI+ cells increased modestly when myeloma IgE was added to the developing mast cells, but increased synergistically when both myeloma IgE and rhIL-4 were present together. Delayed addition of rhIL-4 progressively diminished Fc epsilonRI expression, as did withdrawal of rhIL-4 during the first 2 wk of culture. RhIL-4 selectively increased Fc epsilonRI alpha mRNA levels at least 10-fold. Mast cells developed in the presence of rhIL-4 released tryptase when exposed to anti-Fc epsilonRI alpha. In conclusion, induction of functional Fc epislonRI on recombinant human stem cell factor-dependent human fetal liver-derived mast cells by rhIL-4 harmonizes with the well-accepted ability of this cytokine to enhance IgE production by B cells.
Functional role for the myeloid differentiation antigen CD14 in the activation of human monocytes by IL-2.
Authors: Bosco M C , Espinoza-Delgado I , Rowe T K , Malabarba M G , Longo D L , Varesio L 
Published: December 2022

Abstract
Human monocytes express functional IL-2Rs and are directly activated by IL-2 to exert effector and secretory functions. In this study, we demonstrate that the myeloid differentiation Ag CD14 participates in monocyte activation by IL-2. Engagement of CD14 by specific mAbs resulted in the selective and dose-dependent suppression of IL-2-induced, but not of IFN-gamma-induced, monocyte tumoricidal activity. Furthermore, anti-CD14 mAbs effectively inhibited the secretion of IL-8 and IL-1beta in response to IL-2. Preincubation of monocytes with mAbs directed to selected epitopes on CD14 blocked the binding of IL-2 to the cell surface, providing a possible explanation for the inhibition of IL-2-triggered responses. A critical role for CD14 in IL-2-mediated monocyte activation was further demonstrated by experiments with the human U937 promonocytic cell line. These cells are negative for CD14 and unresponsive to IL-2 despite the expression of the beta and gamma subunits of the IL-2R. U937 cells acquired the capacity to respond to IL-2 following transfection with the human CD14 cDNA (U937/CD14). Stimulation of U937/CD14 cells with IL-2 up-regulated the constitutive levels of IL-8 mRNA, whereas no change in IL-8 mRNA basal expression was observed in control cells transfected with the vector alone (U937/Neo). Accordingly, increased secretion of IL-8 by U937/CD14, but not by U937/Neo cells, was detected following exposure to IL-2. Expression of IL-1beta was also augmented by IL-2 in U937/CD14 cells. These data provide the first evidence that CD14 expression is required for the response of monocytic cells to IL-2.
Cutaneous injection of RANTES causes eosinophil recruitment: comparison of nonallergic and allergic human subjects.
Authors: Beck L A , Dalke S , Leiferman K M , Bickel C A , Hamilton R , Rosen H , Bochner B S , Schleimer R P 
Published: December 2022

Abstract
RANTES, a member of the C-C chemokine family, is a potent chemoattractant for T lymphocytes and eosinophils, but not neutrophils. To determine the effect of RANTES on cell recruitment in vivo, we injected up to 4 microg of RANTES intradermally into both allergic and nonallergic subjects and obtained biopsies 30 min, 6 h, and 24 h later. A dose- and time-dependent recruitment of eosinophils, CD45RO+ cells, and CD3+ cells was observed, with no effect seen on polymononuclear, cutaneous lymphocyte Ag+, CD68+, or tryptase+ cells. Eosinophil recruitment occurred more rapidly in allergic subjects than in nonallergic subjects. No eosinophil infiltrate was observed in nonallergic biopsies at 30 min and 6 h, whereas significant eosinophil recruitment was observed in allergic subjects by 30 min, reaching near-maximum levels by 6 h. The peak responses at 24 h were similar in both groups (nonallergic, 110 +/- 24 eosinophils/mm2; allergic, 113 +/- 38 eosinophils/mm2). The two groups had comparable numbers of circulating eosinophils. Major basic protein staining demonstrated eosinophil degranulation in both allergic and nonallergic groups. RANTES injection resulted in activation of endothelial E-selectin expression at 24 h. Incubation of cultured HUVECs with RANTES had no effect on adhesion molecule expression, suggesting that the in vivo effect may have been indirect. Our studies demonstrate that RANTES is a potent chemoattractant for eosinophils, CD3+ cells, and CD45RO+ cells in human skin. The accelerated eosinophil recruitment in allergic subjects provides support for the hypothesis that eosinophils from these subjects are primed in vivo.
Defective TCR-mediated signaling in synovial T cells in rheumatoid arthritis.
Authors: Maurice M M , Lankester A C , Bezemer A C , Geertsma M F , Tak P P , Breedveld F C , van Lier R A , Verweij C L 
Published: December 2022

Abstract
In rheumatoid arthritis (RA), the functional status of T cells is incompletely understood. Synovial T cells display phenotypic evidence of former activation, but there is poor production of T cell-derived cytokines in the synovium. In addition, synovial T cell proliferation upon mitogenic and antigenic stimulation was decreased compared with that in peripheral blood T cells. Moreover, previous reports revealed that early Ca2+ rises induced by TCR/CD3 stimulation were decreased in RA T cells compared with those in healthy controls. To investigate the molecular mechanisms of RA synovial T cell hyporesponsiveness, we analyzed the TCR/CD3-mediated protein tyrosine phosphorylation in RA peripheral blood and synovial fluid (SF) T cells. SF T cells exhibited a decreased overall tyrosine phosphorylation pattern upon stimulation. Most notably, the induction of phosphorylation of p38 was virtually absent. Moreover, we found that tyrosine phosphorylation of the TCR zeta-chain, one of the most proximal events in TCR signaling, is clearly diminished in RA SF T cells. The decrease in tyrosine phosphorylation was accompanied by a decrease in detectable levels of zeta-protein within synovial T cells. These results suggest that a defective TCR signaling underlies the hyporesponsiveness of synovial T cells in RA.
Reduced expression of Tap1 and Lmp2 antigen-processing genes in the nonobese diabetic (NOD) mouse due to a mutation in their shared bidirectional promoter.
Authors: Yan G , Fu Y , Faustman D L 
Published: December 2022

Abstract
The MHC is an essential contributor to autoimmunity. Lmp2 and Tap1 are genes located in the MHC class II region, and they encode proteins participating in the generation and transport of endogenous peptides for T cell education. A mutation (T--&gt;A) has now been detected in the shared bidirectional promoter of the Lmp2 and Tap1 genes in the nonobese diabetic (NOD) mouse. The nucleotide substitution (TCATTC--&gt;TCAATC) in NOD mice eliminates an initiator (Inr) element (TCATTC) thought to be important for RNA polymerase II positioning in the Lmp2 orientation. It also created a CAAT-like box and an inverted CAAT-like box in the Lmp2 and Tap1 orientations, respectively. Northern blot revealed reduced amounts of Tap1 and Lmp2 mRNA in NOD mice, and 5'-rapid amplification of cDNA ends revealed the loss of a transcription start site of Lmp2 in these animals. The Tap1-Lmp2 promoter from NOD mice showed reduced transcriptional activity in transient transfection assays with luciferase reporter constructs for both Tap1 and Lmp2 genes. Observed altered substrate specificity of Lmp2 containing proteasomes isolated from NOD mice was consistent with reduced Lmp2 activity. The beneficial influence of non-MHC genes (NOR mice) and gender factors (male NOD mice) influencing the penetrance of the promoter polymorphism further confirmed the essential gender and hormonal context of the mutation. This study identifies the first specific mutation in the MHC of the NOD mouse that specifically impacts the activity of genes involved in peptide presentation, a process essential for T cell education.