bluuebunny/crossref_metadata_2025_split huggingface dataset:
Generation of diversity in mammalian gut-associated lymphoid tissues: restricted V gene usage does not preclude complex V gene organization.
Authors: Reynaud C A , Dufour V , Weill J C 
Published: December 2022

Abstract
The sheep genome contains 60 to 90 V lambda genes distributed in least 6 different families, whereas 37 V lambda genes and 10 families exist in humans. Comparison with human V lamda sequences indicates that sheep V lambda genes display less overall sequence divergence, but are closer to the genes most frequently used in the human peripheral repertoire. In both species, 2 to 3 genes contribute half of the expressed sequences. Therefore, similar large combinatorial potential and restriction of the expressed repertoire can exist in two species whose strategy of diversification differs widely (ongoing rearrangement throughout life in human bone marrow vs postrearrangement diversification during early development in sheep ileal Peyer's patches).
Fas and Fas ligand enhance the pathogenesis of experimental allergic encephalomyelitis, but are not essential for immune privilege in the central nervous system.
Authors: Sabelko K A , Kelly K A , Nahm M H , Cross A H , Russell J H 
Published: December 2022

Abstract
Mutations of CD95 and CD95L, lpr and gld, respectively, are associated with spontaneous autoimmune disease and alteration of immune privilege. In lpr or gld animals these processes would be expected to exacerbate experimental allergic encephalomyelitis (EAE), an animal model of the autoimmune demyelinating disease multiple sclerosis. However, here we show that the lpr and gld mutations did not overcome the MHC-defined limits of disease and, surprisingly, did not exacerbate the pathology of EAE on a sensitive haplotype. In fact, the mutations dramatically ameliorated clinical signs of EAE without affecting the development of a Th1 response or inflammatory cell infiltration into the central nervous system. Fewer apoptotic cells were detected in inflammatory lesions of lpr mice than in wild-type lesions of similar severity. Our results indicate that CD95L is not an instrumental component of immune privilege in the central nervous system, and that functional CD95 and CD95L are important for the progression of clinical disease.
Mitogenicity of DNA from different organisms for murine B cells.
Authors: Sun S , Beard C , Jaenisch R , Jones P , Sprent J 
Published: December 2022

Abstract
Recent evidence that DNA from bacteria causes polyclonal activation of mouse B cells raises the question of whether DNA from other organisms has similar properties. Extending prior studies on bacteria and insects, we show here that the capacity of DNA to stimulate B cells correlates closely with hypomethylation of DNA CpG dinucleotide motifs. Thus strong stimulation of B cells was seen with DNA from various organisms displaying little or no methylation of CpG motifs, i.e., yeast, nematodes, and molluscs in addition to bacteria and insects. For these organisms, DNA induced nearly all B cells (including small resting B cells) to up-regulate the activation marker, CD69, and caused many B cells to enter the cell cycle, indicative of polyclonal activation; this effect was not seen after selective methylation of CpG motifs (tested on yeast DNA). By contrast, no stimulation of B cells was seen with DNA from organisms whose CpG motifs are heavily methylated, i.e., various vertebrates (mammals, fish, and frogs) and plants (corn). Despite this correlation, DNA prepared from two murine cell lines exhibiting hypomethylation of CpG motifs caused little or no stimulation of B cells. Thus, the idea that the stimulatory properties of DNA correlate solely with the presence of unmethylated CpG motifs may be an oversimplification.
B cells in the bursa of Fabricius express a novel C-type lectin gene.
Authors: Goitsuka R , Chen C H , Cooper M D 
Published: December 2022

Abstract
The avian bursa of Fabricius provides an essential microenvironment for B cell development and Ab repertoire expansion by a gene conversion mechanism. To explore regulatory interactions between B lineage cells and the bursal microenvironment, we sought to identify genes encoding cell surface molecules selectively expressed on bursal B cells. We report in this work the identification of the chB1 gene that encodes a C-type lectin molecule that is a distant relative of the mammalian B cell differentiation Ag, CD72. The chB1 gene is expressed by intrabursal B cells and a B cell line, DT40, that also diversifies its Ig V region genes by gene conversion. Two forms of this type II membrane protein, differing in their cytoplasmic domains, are generated by the differential usage of two translational initiation sites. The longer chB1 isoform, which is the most abundant, contains a consensus immunoreceptor tyrosine-based inhibitory motif in its cytoplasmic domain. Cross-linkage of the chB1 molecules inhibits proliferation of bursal B cells and the DT40 cell line. The chB1 lectin-like molecule may thus modulate intrabursal B cell development.
Induction of T cell clonal anergy results in resistance, whereas CD28-mediated costimulation primes for susceptibility to Fas- and Bax-mediated programmed cell death.
Authors: Boussiotis V A , Lee B J , Freeman G J , Gribben J G , Nadler L M 
Published: December 2022

Abstract
Since TCR-mediated stimulation induces T cells to become sensitive to Fas-mediated activation-induced cell death (Fas-AICD), we examined whether anergized and CD28-costimulated T cell clones were equally sensitive to Fas-AICD. Here, we show that TCR signal in the presence or absence of CD28 costimulation induced equivalent expression of Fas and Fas ligand. Although anergized cells expressed Fas and Fas ligand, they were resistant to Fas-AICD. Induction of anergy resulted in up-regulation and persistent expression of moderate amounts of bcl-xL and bax and absence of induction of bad. In contrast, CD28-costimulated cells that also expressed Fas and Fas ligand were initially resistant to Fas-AICD but became susceptible after 72 h of culture. Although Fas-mediated apoptosis was the major mechanism of AICD, the IL-1beta-converting enzyme-like protease inhibitor zVAD-FMK totally abrogated DNA fragmentation but not cell death, suggesting that additional Fas-independent apoptotic mechanisms were also operative. Resistance to apoptotic cell death was temporally associated with a dramatic increase of bcl-xL and the presence of bcl-xL:bax heterodimers. Subsequent sensitivity to AICD was associated with down-regulation of bcl-xL, induction of bad, and the displacement of bax from bcl-xL:bax heterodimers. Although induced following CD28 costimulation, bcl-2 did not protect against AICD. Therefore, besides its role in promotion of viability, prevention of anergy, and clonal expansion, CD28 costimulation also has a central role in the induction of subsequent AICD by up-regulating apoptotic mediators.
Regulation of human monocyte apoptosis by the CD14 molecule.
Authors: Heidenreich S , Schmidt M , August C , Cullen P , Rademaekers A , Pauels H G 
Published: December 2022

Abstract
Bacterial products such as LPS have been shown to activate monocytes and to increase CD14 expression, while anti-inflammatory cytokines, i.e., IL-4, down-regulate CD14. Furthermore, activation of monocytes increases survival, whereas deactivation evokes apoptosis (programmed cell death, PCD). This correlation among activation, CD14 expression, and the lifespan of the cells prompted us to investigate the role of CD14 in monocyte apoptosis. The effects of LPS and IL-4 on the expression of CD14, indicated by binding of Leu M3 Ab, and PCD of monocytes were studied simultaneously and in a kinetic fashion by multiparameter flow cytometry. Monocyte PCD was determined by binding of FITC-conjugated annexin V, which indicates apoptotic cell death in early stages, and was confirmed using well-established detection methods, i.e., DNA electrophoresis, electron microscopy, or colorimetric DNA staining. The present study shows that the LPS-induced increase in CD14 expression rescued monocytes from apoptosis, whereas IL-4 treatment first down-regulated CD14 expression and consecutively evoked apoptosis. CD14-/annexin V- monocytes were not apoptotic as confirmed by DNA electrophoresis, whereas CD14-/ annexin V+ monocytes showed clear apoptotic features. Kinetic studies ruled out that monocytes first bound annexin V and later lost the CD14 Ag. Other molecules, such as HLA-A, -B, and -C Ags, were not down-regulated during apoptosis. Enzymatic removal of membrane-bound CD14 by phosphatidylinositol-specific phospholipase C evoked PCD similarly to IL-4. These results suggest that regulation of CD14 receptor expression is an early effector mechanism mediating life or death of monocytes. Down-regulation or removal of the receptor triggers apoptosis, whereas up-regulation promotes survival.
In vivo T helper cell response to retro-inverso peptidomimetics.
Authors: Mézière C , Viguier M , Dumortier H , Lo-Man R , Leclerc C , Guillet J G , Briand J P , Muller S 
Published: December 2022

Abstract
Peptide analogues containing reversed peptide bonds between each residue along the peptide sequence (retro-inverso modification) have been analyzed for their antigenic and in vivo immunogenic properties in the MHC II and Th cell response context. Two antigenic peptides were selected for this study, namely peptide 103-115 of poliovirus VP1, which is involved in the production of Abs that neutralize the infectivity of the virus, and peptide 435-446 from the third constant region of mouse heavy chain IgG2a allopeptide gamma 2ab, which mimics a corneal Ag implicated in autoimmune keratitis. In a competition assay performed in vitro using reference hybridomas of known MHC class II restriction, both retro-inverso analogues bound (although more weakly in our test) to I-Ad and/or I-Ed class II molecules. However, in both cases, this lower affinity was apparently largely compensated in vivo, as a T cell response (with IL-2 secretion), equivalent to that obtained with the wild-type peptides, was observed following immunization of BALB/c mice with the retro-inverso analogues. Moreover, these T cells proliferated and produced IL-2 in response to the cognate peptides. It is concluded that the T cell receptors of T cells primed in vivo with the retro-inverso analogues readily cross-react with parent and retro-inverso analogue-MHC complexes. The approach of using pseudopeptides containing changes involving the backbone, and not the orientation of side chains, may thus be promising to design potent immunogens for class II-restricted T cells.
Regulation of B lymphocyte development and activation by the CD19/CD21/CD81/Leu 13 complex requires the cytoplasmic domain of CD19.
Authors: Sato S , Miller A S , Howard M C , Tedder T F 
Published: December 2022

Abstract
B lymphocyte development and function are regulated in part by the CD19 cell surface receptor complex, which is composed of at least four proteins; CD19, CD21 (CR2, complement receptor 2), CD81, and Leu 13. Because this complex has eight membrane-spanning domains and six cytoplasmic regions, determining the molecular basis for its function and signal transduction activities has not been straightforward. In this study, the contribution of the CD19 cytoplasmic domain to the in vivo function of the CD19/CD21/CD81/Leu 13 complex was assessed by generating CD19-deficient mice that expressed a transgene that encoded only the extracellular and transmembrane domains of CD19. Mice expressing this transgene were similar, if not identical, to CD19-deficient mice with abnormal B cell development, a lack of B-1 cells, increased surface IgM levels on B cells, modest mitogen responses, minimal serum Ig levels, and low humoral immune responses. The results of this study indicate that specific signals generated through the cytoplasmic domain of CD19 are essential for B lymphocyte development and function, and that CD19 is the dominant signaling component of the CD19 complex. Moreover, expression of the CD19 cytoplasmic domain is required for optimal signaling through the B cell Ag receptor complex.
Cytotoxic activities of recombinant soluble murine lymphotoxin-alpha and lymphotoxin-alpha beta complexes.
Authors: Mackay F , Bourdon P R , Griffiths D A , Lawton P , Zafari M , Sizing I D , Miatkowski K , Ngam-ek A , Benjamin C D , Hession C , Ambrose C M , Meier W , Browning J L 
Published: December 2022

Abstract
Human lymphotoxin-alpha (LT alpha) is found in a secreted form and on the surface of lymphocytes as a complex with a second related protein called lymphotoxin-beta (LT beta). Both secreted human LT alpha and TNF have similar biological activities mediated via the TNF receptors, whereas the cell surface LT alpha beta complex binds to a separate receptor called the LT beta receptor (LT beta R). The murine LT alpha and LT beta (mLT alpha and mLT beta) proteins have never been characterized. When recombinant mLT alpha was produced by either of several methods, the protein had a very low specific activity relative to that of human LT alpha in the conventional WEHI 164 cytotoxicity bioassay. The weak activity observed was inhibited by a soluble murine TNF-R55 Ig fusion protein (mTNF-R55-Ig), but not by mLT beta R-Ig. Coexpression of both mLT alpha and a soluble version of mLT beta in insect cells led to an LT alpha beta form that was cytotoxic in the WEHI 164 assay via the LT beta R. To determine whether natural mLT alpha-like forms with cytotoxic activity comparable to that of secreted human LT alpha were secreted from primary spleen cells, splenic lymphocytes were activated in various ways, and their supernatants were analyzed for cytotoxic activity. Using specific Abs to distinguish between mTNF and mLT, a TNF component was readily detected; however, there was no evidence for a secreted mLT alpha cytotoxic activity using this assay. Combined, these observations suggest that secreted mLT alpha may not play a role in the mouse via interactions with TNF-R55, and the ramifications of this hypothesis are discussed.
TCR-delta gene rearrangement and selection during fetal thymocyte development.
Authors: Wilbert O M , Weber-Arden J , Kabelitz D , Arden B 
Published: December 2022

Abstract
TCR delta-chain gene rearrangements were analyzed at different stages of thymic ontogeny. The VDJ delta junctional sequences of the dominantly expressed TCR delta-chain V7 subfamily are highly conserved in fetal and neonatal thymocytes. They are equally conserved in C delta-targeted mice lacking cell surface expression of gamma delta receptors, indicating evolutionary selection acting at the level of DNA rearrangement. Yet, in C delta-mutant mice, the frequency of in-frame transcripts is reduced to 61%, from 88% in wild-type mice, suggesting cellular selection of this DV7-overexpressing gamma delta thymocyte subset. In contrast, in genomic DNA rearrangements, no difference was found in the frequency of productive rearrangements between mutant (26%) and wild-type mice (31%). This in-frame rate, characteristic of random rearrangements, indicates that positive selection is not required for thymic maturation of gamma delta T cells. The results are discussed with regard to models of alpha beta/gamma delta lineage commitment.
Position-dependent variegation of a CD4 minigene with targeted expression to mature CD4+ T cells.
Authors: Boyer O , Zhao J C , Cohen J L , Depetris D , Yagello M , Lejeune L , Bruel S , Mattéï M G , Klatzmann D 
Published: December 2022

Abstract
The CD4 gene follows a complex and highly regulated pattern of expression throughout T cell development. This expression is governed by different regulatory elements that have been partly identified, including a promoter, a proximal enhancer, and a silencer. Here we show that a CD4 minigene comprising a combination of these elements is specifically expressed in mature CD4+ T cells of transgenic mice, but not in CD4+CD8+ double positive thymocytes. The proportion of transgene-expressing CD4+ T cells was constant within a given transgenic line, but varied greatly from one line to another. We demonstrate that this pattern of expression is due to integration of the transgene within or in the vicinity of centromeric heterochromatin. This position-effect variegation demonstrated with a short CD4 transgene has not been observed with larger ones containing additional regulatory sequences, suggesting that the CD4 gene contains a locus control region. Such position-dependent effects must be taken into consideration when developing transgenic models or gene transfer vectors because they can result in the absence of transgene expression in a subpopulation of target cells. Finally, the combination of the CD4 gene silencer, proximal enhancer, and promoter provides an interesting tool to selectively express genes of interest in mature CD4+ T cells of transgenic mice and for the development of gene therapy vectors.
IFN-gamma is not required in the IL-12 response to vesicular stomatitis virus infection of the olfactory bulb.
Authors: Komatsu T , Reiss C S 
Published: December 2022

Abstract
In this report, the role of IFN-gamma in host defense to exogenous IL-12 and clearance of vesicular stomatitis virus (VSV) from the central nervous system was examined. Wild-type and IFN-gamma knockout mice infected with VSV were treated with IL-12 or medium. In both groups, IL-12 treatment resulted in 1) substantially decreased VSV titers in brain homogenates and diminished immunohistochemical detection of VSV Ags in tissue sections; 2) induction of types 1, 2, and 3 nitric oxide synthase; and 3) induction of MHC molecules and rapid infiltration of both T cells and NK cells. These results suggest that IFN-gamma production, both systemically and in the olfactory bulb, contributes to but is not essential for clearance of VSV from the brain. Neutralization of TNF-alpha in IFN-gamma knockout mice mice treated with IL-12 was accompanied by the same immunohistochemical changes, implying that neither IFN-gamma nor TNF-alpha was required. In vitro studies using purified IL-12 or IFN-gamma in culture medium induced nitric oxide synthase isoforms in neurons, glia, and macrophages, and MHC II on glia and macrophages. These data suggest that IL-12 directly activates neurons to promote viral clearance in vivo.
CD28/B7 interactions are required for sustaining the graft-versus-leukemia effect of delayed post-bone marrow transplantation splenocyte infusion in murine recipients of myeloid or lymphoid leukemia cells.
Authors: Blazar B R , Taylor P A , Boyer M W , Panoskaltsis-Mortari A , Allison J P , Vallera D A 
Published: December 2022

Abstract
Graft-vs-leukemia (GVL) can reduce relapse rates after bone marrow transplantation (BMT). Delayed lymphocyte infusion (DLI) post-BMT can mediate a potent GVL effect with less graft-vs-host disease (GVHD) than would be observed if given early post-BMT. In vivo CD28/B7 blockade can reduce GVHD lethality, and B7 ligand expression can augment an antitumor immune response in mice. To examine the role of CD28/B7 interactions in DLI-mediated GVL, we established murine allogeneic BMT models in C57BL/6 (B6) recipients of C1498 (B6 acute myeloid leukemia) or EL4 (B6 acute T cell leukemia) that closely mimic human GVL. Recipients of C1498 and DLI had a marked reduction in relapse. GVL was blocked by anti-B7 mAb infusion. In contrast, recipients of EL4 cells and B10.BR DLI had a more modest GVL effect. The forced expression of B7-1 on EL4 cells markedly augmented the GVL effect of DLI, in contrast to the forced expression of B7-2 on EL4 cells. Relapse rates observed in recipients of C1498-B7-1 and DLI were significantly lower than in recipients of parental C1498 cells. We conclude that the administration of anti-B7 mAbs may impair the GVL effect of DLI and that the forced expression of B7-1 ligands stimulates a GVL effect without adversely affecting the GVHD lethality effect of DLI.
Interaction of IgA with Fc alpha receptors of human mesangial cells activates transcription factor nuclear factor-kappa B and induces expression and synthesis of monocyte chemoattractant protein-1, IL-8, and IFN-inducible protein 10.
Authors: Duque N , Gómez-Guerrero C , Egido J 
Published: December 2022

Abstract
The mechanisms of glomerular damage in IgA nephropathy remain undefined. Mesangial cells (MC) possess Fc receptors for IgA (Fc alpha R), and their occupancy triggers cytokine expression, cell proliferation, and extracellular matrix synthesis. In cultured human MC we examined the effects of soluble IgA aggregates (AIgA) on the activation of nuclear factor-kappa B (NF-kappa B) and the production of proinflammatory chemokines monocyte chemoattractant protein-1 (MCP-1), IL-8, and IFN-inducible protein-10 (IP-10). The exposure of MC to AIgA rapidly activated a NF-kappa B complex constituted of p50 and p65 subunits. NF-kappa B activation was dose dependent, abolished by preincubation with IgA Fc fragments (indicating that AIgA effects occur via specific Fc alpha R), and attenuated by kinase inhibitors. MC stimulation with AIgA increased the mRNA expression of MCP-1, IL-8, and IP-10 in a time- and dose-dependent manner. Maximal expression of IL-8 was observed at 3 h (4.5-fold), while IP-10 and MCP-1 peaked at 6 h (5-fold for both). AIgA also induced biosynthesis and release of the chemokines, which presented biological activity in neutrophil and monocyte chemoattractant assays, peaking at 6 and 9 h, respectively. MC pretreatment with the antioxidant pyrrolidine dithiocarbamate inhibited NF-kappa B activation and chemokine mRNA expression. This study shows that stimulation of Fc alphaR in MC induces gene expression of MCP-1, IL-8, and IP-10, a process partially mediated by NF-kappa B activation. These data may be of importance for a better understanding of the pathogenesis of glomerular damage in IgA immune complex-related diseases.
IL-12 induces IFN-gamma expression and secretion in mouse peritoneal macrophages.
Authors: Puddu P , Fantuzzi L , Borghi P , Varano B , Rainaldi G , Guillemard E , Malorni W , Nicaise P , Wolf S F , Belardelli F , Gessani S 
Published: December 2022

Abstract
We previously reported that resting mouse peritoneal macrophages (PM) constitutively express low levels of IFN-gamma, whose production is consistently enhanced by exogenous IFN-gamma. In this study, we investigated the effects of IL-12 on the replication of vesicular stomatitis virus and on IFN-gamma gene expression in mouse PM. The addition of IL-12 to freshly explanted PM resulted in the persistence of an antiviral state to vesicular stomatitis virus, while control PM progressively became permissive for virus replication after 3 to 4 days in culture. The IL-12-induced antiviral state was inhibited by Abs to IFN-gamma, suggesting that endogenous IFN-gamma was largely responsible for this antiviral response. Moreover, IL-12 induced a consistent secretion of IFN-gamma, especially in cultured PM. The IL-1 2-induced antiviral state and IFN-gamma production were observed using PM from various strains of mice, including LPS-defective C3H/HeJ, NK-deficient bg/bg, DBA/2, Swiss (CD1), and Swiss nude mice treated or not with anti-asialo GM1 Abs. A 4-h treatment with IL-12 was sufficient to induce a marked accumulation of IFN-gamma mRNA, which was greater in cultured PM than in freshly harvested cells. Lastly, immunofluorescence studies in IL-12-stimulated macrophages clearly showed an enhancement of immunoreactive IFN-gamma compared with basal levels in cells exhibiting a macrophage (i.e., F4/80-positive) phenotype. Together, these findings demonstrate that IL-12 can directly stimulate mouse PM to produce IFN-gamma. We suggest that IL-12-induced IFN-gamma production by macrophages can play some role in the generation of the antiviral and immunoregulatory effects of IL-12.