bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mouse CD1 is mainly expressed on hemopoietic-derived cells.
Authors: Brossay L , Jullien D , Cardell S , Sydora B C , Burdin N , Modlin R L , Kronenberg M 
Published: December 2022

Abstract
The mouse CD1 (mCD1) is a class I-like molecule that is encoded outside the MHC. Recent studies demonstrate that mCD1 presents hydrophobic peptides to CD8+ T cells and also that it is recognized by a population of NK1.1+ T cells that are thought to play an immunoregulatory role because of their ability to secrete IL-4. It has previously been reported that mCD1 is expressed predominantly by intestinal epithelial cells, although most NK1.1+ T cells are located elsewhere. We, therefore, have generated new mAbs to mCD1 to investigate its tissue distribution. The principal site of mCD1 expression in normal mice is on cells in the hemopoietic series, including constitutive expression on nearly all T and B cells, on macrophages, and on dendritic cells. Other than bone marrow-derived cells, mCD1 is not widely expressed and is not detectable on great majority of intestinal epithelial cells. The B cells, but not the T cells, from beta2m-deficient mice can be recognized by two mCD1 autoreactive T hybridomas. Therefore, although we could not detect a beta2m-independent form of mCD1 using these mAbs, mCD1 in a different conformation or a mCD1-related molecule is likely to be expressed in the absence of beta2m on some cell types. The pattern of expression of mCD1 correlates with the distribution of NK1 T cells and is consistent with an important Ag-presenting function for this molecule.
Family-specific differences in transcription efficiency of Ig heavy chain promoters.
Authors: Buchanan K L , Smith E A , Dou S , Corcoran L M , Webb C F 
Published: December 2022

Abstract
Murine Ig variable region heavy chain genes (V(H)) are grouped into families based on coding sequence homology. We observed that the accompanying promoter sequences were also conserved in a family-specific manner. Remarkably, no one has directly compared the transcription efficiencies of V(H) genes from different families. Using an in vitro transcription system, we found that transcription efficiencies of different V(H) promoters differed by as much as 70-fold. These differences could be attributed to variation in the octamer-heptamer and TATA sequences, as well as to the presence or absence of initiator elements. The J558 family promoter exhibited the highest level of transcription and specifically interacted with an Oct-1 dimer not bound by other V(H) promoters. These data suggest that differential transcription and regulation of V(H) promoters could occur in vivo. The increased transcription efficiency of the J558 promoter relative to other V(H) promoters also presents a possible explanation for the abundance of J558 sterile transcripts observed before V(H)DJ(H) rearrangement.
Lipopolysaccharide-induced IL-12 expression in the central nervous system and cultured astrocytes and microglia.
Authors: Stalder A K , Pagenstecher A , Yu N C , Kincaid C , Chiang C S , Hobbs M V , Bloom F E , Campbell I L 
Published: December 2022

Abstract
We examined whether the cytokine IL-12 could be induced locally in the brain or in glial cell cultures following LPS treatment. In the brain, expression of IL-12 p35 mRNA was constitutive and did not alter following i.p. injection of LPS. In contrast, IL-12 p40 mRNA was only detectable in the brain of mice given two staggered injections of LPS. Dual labeling in situ analysis revealed IL-12 p40 RNA-positive cells scattered throughout the brain parenchyma, with a small number of these cells being identified as astrocytes, while the majority of IL-12 p40 RNA-expressing cells appeared to be microglia. In cultured microglia or astrocytes, LPS and to a much lesser degree IL-1beta, but not IFN-gamma or TNF-alpha, induced the expression of IL-12 p40 mRNA. Numerous glial fibrillary acidic protein-immunopositive cells colabeled for IL-12 p40 RNA; indicating that LPS-stimulated astrocytes expressed IL-12 in vitro. Immunoblot analysis of lysates from LPS-treated astrocytes revealed the presence of multiple species of 40, 43, 75, and 120 kDa containing the IL-12 p40 protein. Finally, secretion of the IL-12 p75 heterodimer was detectable by ELISA from astrocytes treated with LPS plus IFN-gamma, but not with LPS alone. The findings indicate that IL-12 gene expression can be activated in the brain, with the resident glial cells being a prodigious source of this cytokine. The localized production of IL-12 may have a significant impact on the development of cell-mediated immune responses within the central nervous system.
Immunodominance of a single CTL epitope in a primate species with limited MHC class I polymorphism.
Authors: Evans D T , Piekarczyk M S , Allen T M , Boyson J E , Yeager M , Hughes A L , Gotch F M , Hinshaw V S , Watkins D I 
Published: December 2022

Abstract
MHC class I molecules play a crucial role in immunity to viral infections by presenting viral peptides to cytotoxic T lymphocytes. One of the hallmarks of MHC class I genes in outbred populations is their extraordinary polymorphism, yet the significance of this diversity is poorly understood. Certain species with reduced MHC class I diversity, such as the cotton-top tamarin (Saguinus oedipus), are more susceptible to fatal viral infections. To explore the relationship between this primate's limited MHC class I diversity and its susceptibility to viruses, we infected five cotton-top tamarins with influenza virus. Every tamarin recognized the same immunodominant CTL epitope of the influenza nucleoprotein. Surprisingly, this nucleoprotein peptide was bound by Saoe-G*08, an MHC class I molecule expressed by every cotton-top tamarin. Two tamarins also made a subdominant response to an epitope of the matrix (M1) protein. This peptide appeared to be bound by another common MHC class I molecule. With the exception of an additional subdominant response to the polymerase (PB2) protein in one individual, no other influenza-specific CTL responses were detected. In populations or species with limited MHC class I polymorphism like the cotton-top tamarin, a dependence on shared MHC class I molecules may enhance susceptibility to viral infection, since viruses that evade MHC class I-restricted recognition in one individual will likely evade recognition in the majority of individuals.
Extracellular ATP triggers IL-1 beta release by activating the purinergic P2Z receptor of human macrophages.
Authors: Ferrari D , Chiozzi P , Falzoni S , Dal Susino M , Melchiorri L , Baricordi O R , Di Virgilio F 
Published: December 2022

Abstract
Extracellular ATP (ATPe) is known to cause release of processed IL-1 beta from LPS-treated macrophages and microglial cells. IL-1 beta release is fast and thought to be associated with cell death. We have reinvestigated this process to identify 1) the purinergic receptor involved; 2) the relationship to cell death; and 3) pharmacologic agonists or antagonists able to modulate IL-1 beta release. Our data confirm that ATPe is a powerful stimulus for IL-1 beta release from LPS-treated human macrophages; however, we also show that IL-1 beta release is not necessarily associated with cell death, as it occurs at lower ATP concentrations and much earlier than leakage of cytoplasmic markers. The selective purinergic P2Z receptor agonist benzoylbenzoyl ATP was at least one order of magnitude more powerful than ATP, but also had a strong cytotoxic effect. 2-Methylthio-ATP was equipotent as ATPe at the optimal concentration of 1 mM, but markedly inhibitory at higher concentrations. The irreversible P2Z blocker-oxidized ATP completely inhibited ATPe-induced IL-1 beta release. IL-1 beta release also was inhibited by increasing the K+ concentration of the incubation medium. These data suggest that ATPe triggers IL-1 beta via the purinergic P2Z receptor recently shown to be expressed by human macrophages and identified as a new member of the P2X family (P2X7), and provide pharmacologic tools for the modulation of IL-1 beta release in vitro and, possibly, in vivo.
Absence of functional relevance of human transporter associated with antigen processing polymorphism for peptide selection.
Authors: Daniel S , Caillat-Zucman S , Hammer J , Bach J F , van Endert P M 
Published: December 2022

Abstract
The polymorphic TAP (TAP1 and TAP2) genes code for a heteromeric complex that translocates cytosolic peptides across the membrane of the endoplasmic reticulum where they associate with MHC class I molecules. In the rat, extensive TAP2 polymorphism modifies the spectrum of peptides presented by MHC class I molecules on the cell surface. Although polymorphism of human TAP proteins is more limited, it has been proposed to be associated with susceptibility to autoimmune diseases. To analyze the peptide selectivity and transport efficiency of human TAP alleles, we have generated the most frequent TAP1 and TAP2 alleles using site-directed mutagenesis. Alleles were cloned in the baculovirus expression system and six TAP1/2 allelic combinations were overexpressed in Sf9 insect cells. Microsomes containing TAP1/2 dimers were isolated, and peptide binding assays were performed using random sequence peptide libraries of variable length (7-18 mer) and a 9-mer polyalanine peptide substituted with various amino acids in positions 1, 2, 3, 7, and 9. All studied allelic combinations selected peptides with identical substitutions and length. Furthermore, transport assays showed similar efficiency and kinetics of peptide translocation by the different TAP alleles. These data suggest that the major human TAP alleles transport identical peptide sets and are therefore unlikely to contribute to predisposition to autoimmune diseases.
Assembly and retention of CD1b heavy chains in the endoplasmic reticulum.
Authors: Sugita M , Porcelli S A , Brenner M B 
Published: December 2022

Abstract
The endoplasmic reticulum (ER) is the site for assembly of MHC class I molecules. Newly synthesized class I heavy chains bind calnexin, an ER-resident molecular chaperone, and dissociate from calnexin following association with beta2-microglobulin (beta2m). The class I heavy chain:beta2m complex then is stabilized by binding endogenous peptides transported to the ER through the TAP molecules. Thus, both beta2m and TAP are required for class I Ag presentation. Human CD1b is a beta2m-associated, non-MHC-encoded glycoprotein that functions in presentation of lipid Ags to T cells. Despite its structural similarities with class I, CD1b-mediated Ag presentation is TAP independent, and CD1b traffics to endocytic compartments for sampling exogenous Ags. Given these distinctive features of CD1b, we set out to analyze its assembly. Immunofluorescence microscopic analysis of CD1b-transfected cells with a rabbit heteroantiserum detecting only beta2m-free CD1b heavy chains revealed a reticular pattern characteristic of ER staining. Consistently, CD1b heavy chains recognized by this antiserum were sensitive to endoglycosidase H and associated with calnexin, indicating a distribution restricted to the ER. Furthermore, CD1b heavy chains were confined to the ER in beta2m-negative cells, whereas they exited the ER and distributed in post-Golgi compartments when beta2m was reconstituted in these cells. These results suggested that assembly of CD1b heavy chains with beta2m occurred in the ER and that only assembled CD1b heavy chain:beta2m complexes were able to exit the ER and traffic to endocytic compartments, where they encounter endocytosed lipid Ags.
Human monocyte binding to fibronectin enhances IFN-gamma-induced early signaling events.
Authors: McCarthy J B , Vachhani B V , Wahl S M , Finbloom D S , Feldman G M 
Published: December 2022

Abstract
Leukocyte integrins are fundamentally important in modulating adhesion to extracellular matrix components and to other cells. This integrin-mediated adhesion controls leukocyte arrest and extravasation during the onset of inflammatory responses. Moreover, integrin-ligand interactions trigger signaling pathways that may influence leukocyte phenotype and function at sites of inflammation. In the current studies, we evaluated the combinatorial effects of monocyte adhesion and IFN-gamma on intracellular signaling pathways. IFN-gamma triggers a well-defined signal transduction pathway, which although not directly stimulated by monocyte adherence to fibronectin or arginine-glycine-aspartate (RGD)-coated substrata, was enhanced significantly in these matrix-adherent cells. Compared with monocytes in suspension or adherent on plastic surfaces, monocytes adherent to fibronectin or RGD exhibited a greater than threefold increase in steady state levels of IFN-gamma-induced mRNA for the high affinity Fc gammaRI receptor. By electrophoretic mobility shift assays, this increase in mRNA was associated with a 5- to 10-fold increase in the STAT1-containing DNA-binding complex that binds to Fc gammaRI promoter elements. Furthermore, the tyrosine phosphorylation of STAT1 and the tyrosine kinases JAK1 and JAK2 was enhanced significantly in RGD-adherent monocytes compared with control cells. These results suggest a novel mechanism by which integrin-mediated cell adhesion can modulate the magnitude of cytokine-induced signal transduction pathways, thereby amplifying cellular events leading to monocyte activation and inflammation.
Prevention by anti-LFA-1 of acute myoblast death following transplantation.
Authors: Guérette B , Skuk D , Célestin F , Huard C , Tardif F , Asselin I , Roy B , Goulet M , Roy R , Entman M , Tremblay J P 
Published: December 2022

Abstract
Myoblast transplantation is a potential treatment for Duchenne muscular dystrophy. One of the problems possibly responsible for the limited success of clinical trials is the rapid death of the myoblasts after transplantation. To investigate this problem, myoblasts expressing beta-galactosidase were injected in the tibialis anterior muscles of mice. Beta-galactosidase activity was reduced by 74.7% after 3 days. Myoblast death observed at 3 days was reduced to 57.2% when the hosts were irradiated. This result suggested that host cells were contributing to this phenomenon. Transplantation in SCID and FK506-treated mice did not reduce cell death, indicating that mortality was not due to an acute specific reaction. In contrast, administration of the anti-LFA-1 (TIB-213) mAb markedly reduced myoblast death at 3 days without altering leukocyte tissue infiltration. We postulated that neutrophils were mediating myoblast mortality by an LFA-1-dependent mechanism. To test this hypothesis, IL-1beta-activated myoblasts were loaded with 6-carboxy-2',7'-dichlorodihydrofluorescein diacetate, di(acetoxymethylester) (DCFH), a marker for oxidative stress. Addition of neutrophils and zymosan-activated serum resulted in a time-dependent DCFH fluorescence; this neutrophil-induced oxidation was considerably inhibited by TIB-213. These results indicate that an effective control of the inflammatory reaction will be necessary for any new clinical trials of myoblast transplantation and suggest that neutrophil-mediated myoblast injury occurs by an LFA-1-dependent pathway.
Abnormal regulation of retinoic acid receptor beta2 expression and compromised allograft rejection in transgenic mice expressing antisense sequences to retinoic acid receptor beta1 and beta3.
Authors: Bérard J , Luo H , Chen H , Mukuna M , Bradley W E , Wu J 
Published: December 2022

Abstract
Transgenic mice carrying antisense sequences common to the retinoic acid receptors (RAR) beta1 and beta3 were produced to examine roles of RARbeta1 and beta3 in the immune system. There were no significant changes of endogenous RARbeta1/beta3 expression at the mRNA level in T cells, B cells, and macrophages of the transgenic mice (AS-RARbeta1/beta3 mice). However, there was a decrease of RARbeta1/beta3 protein in the T cells, as expected. Interestingly, a drastic up-regulation (7-10 fold) of RARbeta2 messages and a significant decrease of RARbeta4 messages in AS-RARbeta1/beta3 macrophages were observed compared with that of nontransgenic macrophages. RARbeta2 protein in the transgenic macrophages was also up-regulated. This suggests that there is a dual feedback control for the RARbeta expression. A repressed RARbeta1 and beta3 expression, presumably at the protein level, likely leads to a compensatory up-regulation of RARbeta2 and repression of RARbeta4, which is less active than RARbeta2. The AS-RARbeta1/beta3 mice had no gross abnormality. However, they had compromised rejection response to cardiac allografts. The alloantigen-specific T cell cytotoxicity was reduced, and the macrophage population in the spleen was decreased in these mice. These defects likely contribute to the slower rejection response in the AS-RARbeta1/beta3 mice, the existence of other defects not being excluded. Our study has suggested that RARbeta1 and RARbeta3 are necessary to optimize immune responses.
E-cadherin-mediated adhesion involving Langerhans cell-like dendritic cells expanded from murine fetal skin.
Authors: Jakob T , Saitoh A , Udey M C 
Published: December 2022

Abstract
Langerhans cells (LC), the epidermal contingent of the dendritic cell (DC) lineage, migrate from skin to regional lymph nodes to initiate primary immune responses against Ag encountered in skin. Because E-cadherin mediates LC-keratinocyte adhesion, E-cadherin expression and/or function must be modulated during LC migration. To facilitate studies of LC/DC cadherin biology, we defined culture conditions that allowed expansion of LC-like cells from fetal murine skin. Fetal skin-derived dendritic cells (FSDDC) were propagated from C57BL/6 day 16 fetal skin in GM-CSF- and CSF-1-supplemented media. After 14 days, aggregates of E-cadherin+ FSDDC (FSDDC-A) that resembled freshly-obtained LC with regard to phenotype and function were isolated. Nonadherent FSDDC (FSDDC-NA) with dendritic morphology, surface phenotype identical to that of interdigitating DC and potent allostimulatory capacity were released from FSDDC-A with continued incubation. A survey of cytokine mRNAs expressed by FSDDC revealed that FSDDC-A expressed predominantly TNF-alpha, TGF-beta1, and MIF mRNA. In contrast, FSDDC-NA exhibited de novo expression of IL-1beta, IL-12 (p40), increased levels of TNF-alpha and decreased MIF mRNA. Neutralizing anti-E-cadherin mAb dissociated FSDDC-A into single cells, whereas functionally inactive anti-E-cadherin mAb and mAb reactive with other adhesion molecules did not, demonstrating that adhesion within FSDDC-A was E-cadherin-mediated. FSDDC-A also preferentially adhered to E-cadherin-transfected fibroblasts. Spontaneous dissociation of FSDDC-A was accompanied by a reduction in cell surface E-cadherin expression. The availability of large numbers of cells with characteristics of LC in situ that spontaneously mature into interdigitating DC will permit detailed studies of LC/DC cadherin biology and LC/DC differentiation.
Primary B cell development is impaired in mice with defects of the pituitary/thyroid axis.
Authors: Montecino-Rodriguez E , Clark R G , Powell-Braxton L , Dorshkind K 
Published: December 2022

Abstract
There has been considerable speculation that hormones produced in the anterior pituitary gland act as positive regulators of primary B cell development in the bone marrow. In order to identify endocrine factors that have such a role, B cell differentiation was examined in a panel of mice with genetic mutations that result in compromised production of one or more anterior pituitary hormones. This analysis demonstrated that the frequency of B lineage cells is significantly reduced in the dwarf and hypothyroid strains of mice, which have defects in the pituitary/thyroid axis, and that the production of normal numbers of pre-B cells is particularly dependent upon thyroid hormones. B cell development was normal in Little and IGF-I knockout animals, which have defects in the production of growth hormone and/or insulin-like growth factor I. The dependence of B lymphopoiesis on thyroid hormones appeared to be specific for that lineage, as myelopoiesis and thymopoiesis were normal in dwarf and hypothyroid mice. In addition to describing a specific endocrine hormone involved in the regulation of B cell development, these data provide evidence that normal production of bone marrow B lineage cells is dependent on extramedullary signals.
The mouse genes encoding the third pair of beta-type proteasome subunits regulated reciprocally by IFN-gamma: structural comparison, chromosomal localization, and analysis of the promoter.
Authors: Hayashi M , Ishibashi T , Tanaka K , Kasahara M 
Published: December 2022

Abstract
Proteasomes are the multisubunit protease involved in the generation of peptides presented by MHC class I molecules. When cells are stimulated with IFN-gamma, two MHC-encoded subunits, low Mr polypeptide 2 (LMP2) and LMP7, are incorporated into the proteasomal complex by displacing the housekeeping subunits, designated Y and X, respectively. Recent evidence indicates that besides the LMP2/Y and LMP7/X subunits, there is another pair of structurally similar beta-type subunits, designated MECL1 and Z, whose expression is regulated reciprocally by IFN-y. In the present study we determined the genomic organizations of the mouse genes, Psmb10 and Psmb7, that encode the MECL1 and Z subunits, respectively. Although the two genes differ &gt; 10-fold in size, they both have eight exons, with the exon-intron boundaries located precisely at the equivalent positions. The organization of the Psmb10 and Psmb7 genes differs from those of the genes encoding the other two pairs of IFN-gamma-regulated subunits. Thus, comparison of the gene structures supports the idea that Psmb10 and Psmb7 arose by duplication from an immediate common ancestor. The promoter region of the Psmb10 gene contains two IFN-stimulated response elements, the functionality of which was confirmed by in vitro mutagenesis. The mouse Psmb10 gene maps to chromosome 8, thus outside the MHC like its human counterpart. Besides the Psmb7 gene previously mapped to chromosome 2, a truncated processed pseudogene, designated Psmb7-ps, was identified and mapped to chromosome X.
Involvement of the ras-like GTPase rab3d in RBL-2H3 mast cell exocytosis following stimulation via high affinity IgE receptors (Fc epsilonRI).
Authors: Roa M , Paumet F , Le Mao J , David B , Blank U 
Published: December 2022

Abstract
Aggregation of high affinity IgE receptors (Fc epsilonRI) expressed on mast cells and basophils is a potent stimulus for the release of inflammatory mediators from cytoplasmic granules. Fc epsilonRI-dependent exocytosis requires activation of protein kinase C and mobilization of calcium from intra- and extracellular stores. However, how these events ultimately regulate the membrane fusion step between cytoplasmic granules and the plasma membrane still remains unclear. In this study, we investigated the role of the small GTPases of the rab3 subfamily in the regulated exocytosis following stimulation of rat basophilic leukemia cells (RBL-2H3). Analysis using reverse-transcriptase-based PCR showed that RBL-2H3 cells expressed rab3a and rab3d isoforms, with a predominance of rab3d at the mRNA level. Investigation of the subcellular distribution using isoform-specific Abs demonstrated that the majority of rab3a was expressed in the cytosol, whereas rab3d was found predominantly in the membrane fraction. To determine whether these proteins play a role in Fc epsilonRI-triggered exocytosis, we established RBL-2H3 transfectants that overexpressed wild-type and expressed GTP-binding mutant forms (N135I) of rab3a and rab3d. Whereas expression of rab3a proteins did not significantly affect degranulation as tested by beta-hexosaminidase release, those of both wild-type and mutant rab3d proteins inhibited degranulation. Calculations of the initial fast and of the second slow release rates showed that they are both inhibited about twofold, suggesting that rab3d interferes with a rate-limiting step in Fc epsilonRI-stimulated exocytosis.