bluuebunny/crossref_metadata_2025_split huggingface dataset:
Adenovector-Mediated Expression of Human Thrombopoietin cDNA in Immune-Compromised Mice: Insights into the Pathophysiology of Osteomyelofibrosis
Authors: Frey Beat M. , Rafii Shahin , Teterson Michael , Eaton Dan , Crystal Ronald G. , Moore Malcolm A.S. 
Published: January 2023

Abstract
Thrombopoietin (TPO) cDNA can be effectively delivered in vivo by adenovectors. Immune normal mice (BALB/c) and syngeneic mice with variable degrees of immune dysfunction nu, SCID, and NOD-SCID) were treated with an adenovirus vector expressing the human TPO cDNA (AdTPO). Platelet peaks were significantly higher in SCID and NOD-SCID mice compared with BALB/c and nu mice. Human plasma TPO concentration correlated with the platelet counts. SCID and NOD-SCID mice exhibited also granulocytosis and increased numbers of hemopoietic progenitors in bone marrow. Following platelet peak, BALB/c mice developed autoantibodies against murine TPO leading to thrombocytopenia and depletion of megakaryocytes and hemopoietic progenitors in bone marrow. AdTPO-treated SCID mice developed osteomyelofibrosis and extramedullary/extrasplenal hemopoiesis. In contrast, NOD-SCID mice with a similar magnitude of TPO overexpression did not show fibrotic changes in bone marrow. We conclude, first, that a chronic high level of TPO overexpression stimulates megakaryocytopoiesis and myelopoiesis leading to thrombocytosis and granulocytosis. Second, increased megakaryocytopoiesis is not sufficient for development of secondary osteomyelofibrosis. The functionally deficient monocytes and macrophages of NOD-SCID mice probably prevented fibrotic marrow changes. Third, immune deficiency enhances expression of adenovirally mediated transgenes, and fourth, xenogeneic transgene delivered by adenovector to a host with normal immune functions may induce loss of immune tolerance and autoimmune phenomenon.
A Periarteriolar Lymphoid Sheath-Associated B Cell Focus Response Is Not Observed During the Development of the Anti-Arsonate Germinal Center Reaction
Authors: Vora Kalpit A. , Tumas-Brundage Kathleen M. , Manser Tim 
Published: January 2023

Abstract
The behavior of p-azophenylarsonate (Ars)-specific B cell clones during the primary T cell-dependent splenic response of A/J mice was investigated using an immunohistochemical approach. The earliest Ars-specific B cells were observed as isolated cells in the red pulp by day 3 after immunization with Ars-keyhole limpet hemocyanin, (KLH) and at day 6, large clusters of Ars-specific B cells were first detected in germinal centers, which continued to be observed for an additional 8 to 15 days. Surprisingly, no Ars-specific B cell foci were observed in or near the CD4 T cell-rich periarteriolar lymphoid sheath (PALS) during the entire primary response. Nevertheless, A/J mice immunized with (4-hydroxy-3-nitrophenyl)acetyl-chicken gamma globulin (NP-CGG) or Ars-CGG mounted robust splenic (4-hydroxy-3-nitrophenyl)acetyl or CGG-specific PALS-associated focus reactions, respectively. In contrast, no Ars-specific PALS B cell foci were detected in A/J mice immunized with Ars-CGG. These data add to a growing body of evidence indicating that B cell proliferation and differentiation in CD4 T cell-rich microenvironments are not prerequisites for the GC reaction. Taken together with previous results obtained using other model Ags, the data suggest that the specificity of the B cell Ag receptor may strongly influence the lymphoid microenvironment in which a B cell clone first undergoes Ag-driven clonal expansion and differentiation.
Aberrant Intermolecular Disulfide Bonding in a Mutant HLA-DM Molecule: Implications for Assembly, Maturation, and Function
Authors: Busch Robert , Doebele Robert C. , von Scheven Emily , Fahrni Jimothy , Mellins Elizabeth D. 
Published: January 2023

Abstract
HLA-DM (abbreviated DM) is an MHC-encoded glycoprotein that catalyzes the selective release of peptides, including class II-associated invariant chain peptides, from MHC class II molecules. To perform its function, DM must assemble in the endoplasmic reticulum (ER), travel to endosomes, and interact productively with class II molecules. We have described previously an EBV-transformed B cell line, 7.12.6, which displays a partial Ag presentation defect and expresses a mutated DM β-chain with Cys79 replaced by Tyr. In this study, we show that HLA-DR molecules in 7.12.6 have a defect in peptide loading and accumulate class II-associated invariant chain peptides (CLIP). Peptide loading is restored by transfection of wild-type DMB. The mutant DM molecules exit the ER slowly and are degraded rapidly, resulting in greatly reduced levels of mutant DM in post-Golgi compartments. Whereas wild-type DM forms noncovalent αβ dimers, such dimers form inefficiently in 7.12.6; many mutant DM β-chains instead form a disulfide-bonded dimer with DM α. Homodimers of DM β are also detected in 7.12.6 and in the α-chain defective mutant, 2.2.93. We conclude that during folding of wild-type DM, the native conformation is stabilized by a conserved disulfide bond involving Cys79β and by noncovalent contacts with DM α. Without these interactions, DM β can form malfolded structures containing interchain disulfide bonds; malfolding is correlated with ER retention and accelerated degradation.
Lack of Local Suppression in Orally Tolerant CD8-Deficient Mice Reveals a Critical Regulatory Role of CD8+ T Cells in the Normal Gut Mucosa
Authors: Grdic Dubravka , Hörnquist Elisabeth , Kjerrulf Martin , Lycke Nils Y. 
Published: January 2023

AbstractWe found that feeding keyhole limpet hemocyanin (KLH) to CD8-deficient (CD8−/−) mice induced oral tolerance that was comparable in both magnitude and quality to that induced in wild-type (wt) mice. The tolerance was dose dependent, and only higher doses of KLH caused significant reduction in specific Ab and T cell responses. Both Th1 and Th2 CD4+ T cell functions were affected. Feeding KLH together with cholera toxin (CT) adjuvant, however, abrogated the induction of oral tolerance equally well in CD8−/− and wt mice. On the contrary, CT adjuvant was unable to abrogate already established oral tolerance in both CD8−/− and wt mice. Most importantly, whereas Ag feeding induced hyporesponsiveness in systemic as well as in local gut IgA responses in wt mice, a lack of local suppression was evident in orally tolerant CD8−/− mice following oral immunizations. Thus, contrary to the situation in wt mice, Ag feeding induces systemic, but not local, gut IgA hyporesponsiveness in CD8−/− mice, suggesting that CD8+ T cells in the normal gut mucosa exert an important down-regulatory function. In wt mice the local suppression extended to an unrelated Ag, OVA, given together with KLH and CT adjuvant, i.e., bystander suppression. Based on these results we propose that tolerance induced by feeding Ag is highly compartmentalized, requiring CD8+ T cells for local suppression of IgA responses, whereas systemic tolerance may affect CD4+ T cells of both Th1 and Th2 types independently of CD8+ T cells. Finally, the adjuvant effect of CT abrogates induction, but not established, oral tolerance through a mechanism that does not require CD8+ T cells.
Degenerate Recognition of Alloantigenic Peptides on a Positive-Selecting Class I Molecule
Authors: Tallquist Michelle D. , Weaver Arthur J. , Pease Larry R. 
Published: January 2023

Abstract
The well-defined 2C T cell was used to investigate alloreactive degeneracy. A panel of class I molecules that are known ligands for the 2C TCR were sensitized with three known peptide ligands, p2Ca (LSPFPFDL), dEV-8 (EQYKFYSV), and SIYR-8 (SIYRYYGL). The peptide p2Ca was originally identified as the allopeptide seen in the Ld class I molecule by 2C T cells, 2C recognizes the dEV-8 peptide as the ligand in the Kbm3 class I molecule, and SIYR-8 was recently identified as a peptide ligand for 2C in the context of the Kb class I molecule. Strong recognition of all three Ag-presenting molecules occurred in the context of their respective allopeptides, but 2C recognized all three peptides to a measurable extent in the context of Kb. Molecular modeling of these Kb/peptide complexes revealed a high degree of similarity between dEV-8 and SIYR-8, but very little conformational similarity of either of these peptides with p2Ca. Furthermore, the structural changes in the mutant Kbm3 binding site resulted in generalized changes in the conformation of each of five bound peptides compared with those of the same peptides bound to Kb. The finding that degenerate recognition occurs on Kb, the restriction element responsible for selecting 2C T cells, suggests a unique relationship between a TCR and the Ag-presenting molecule that mediates its positive selection.
In Vitro and In Vivo Mechanisms of Action of the Antiproliferative and Immunosuppressive Agent, Brequinar Sodium
Authors: Xu Xiulong , Williams James W. , Shen Jikun , Gong Haihua , Yin Deng-Ping , Blinder Leonard , Elder Robert T. , Sankary Howard , Finnegan Alison , Chong Anita S.-F. 
Published: January 2023

Abstract
Intracellular pyrimidine nucleotides (PyN) can be synthesized de novo from glutamine, CO2, and ATP, or they can be salvaged from preformed pyrimidine nucleosides. The antiproliferative and immunosuppressive activities of brequinar sodium (BQR) are thought to be due to the inhibition of the activity of dihydroorotate dehydrogenase, which results in a suppression of de novo pyrimidine synthesis. Here we describe the effects of the pyrimidine nucleoSide, uridine, on the antiproliferative and immunosuppressive activities of BQR. In vitro reduction of PyN levels in Con A-stimulated T cells and inhibition of cell proliferation by low concentrations of BQR (≤65 μM) are reversed by uridine. However, uridine is unable to reverse the effects of high concentrations of BQR (≥65 μM). The ability of BQR to induce anemia in BALB/c mice is prevented by the coadministration of uridine. In contrast, the immunosuppressive activity of BQR is unaffected by similar doses of uridine. PyN levels in the bone marrow, but not in the spleen, are depressed in mice treated with BQR. These observations suggest that the induction of anemia by BQR is due to depletion of intracellular PyN in hemopoietic stem cells located in the bone marrow. They also suggest that the mechanism of immunosuppression by BQR may be only marginally dependent on depletion of intracellular PyN in lymphocytes located in the periphery. We report a novel activity of BQR: inhibition of tyrosine phosphorylation, and hypothesize that the immunosuppressive activity may be due, in part, to this unsuspected ability of BQR to inhibit tyrosine phosphorylation in lymphocytes.
CpG DNA Is a Potent Enhancer of Specific Immunity in Mice Immunized with Recombinant Hepatitis B Surface Antigen
Authors: Davis Heather L. , Weeranta Risini , Waldschmidt Thomas J. , Tygrett Lorraine , Schorr Joachim , Krieg Arthur M. 
Published: January 2023

Abstract
Unmethylated CpG dinucleotides in bacterial DNA or synthetic oligodeoxynucleotides (ODN) cause B cell proliferation and Ig secretion, monocyte cytokine secretion, and activation of NK cell lytic activity and IFN-γ secretion in vivo and in vitro. The potent immune activation by CpG ODN suggests possible utility for enhancing immune responses to vaccines. Mice immunized with recombinant hepatitis B virus surface Ag and a CpG ODN as an immune enhancer have titers of Abs against HBsAg (anti-HBs) that are five times higher than those of mice immunized with HBsAg and the standard adjuvant, aluminum hydroxide (alum). Ab titers in mice immunized with HBsAg and both CpG ODN plus alum were 35 times higher than the titers in mice immunized with alum alone, indicating a strong synergistic interaction between the CpG ODN and alum. ODN without CpG motifs had little or no immune-enhancing activity at the doses used herein. Alum induces a Th2 humoral response (mostly IgG1) and no CTL. In contrast, CpG ODN gives a strong Th1 response with predominantly IgG2a Abs and CTL, even when mixed with alum. In vitro studies to determine possible mechanisms of CpG immune-enhancing effects show that CpG ODN induce expression of costimulatory molecules on Ag-presenting cells and drive B cell isotype switching in the appropriate cytokine milieu. These studies demonstrate that CpG ODN are promising new immune enhancers for vaccination applications.
Recognition of an Antigenic Peptide Derived from Tyrosinase-Related Protein-2 by CTL in the Context of HLA-A31 and -A33
Authors: Wang Rong-Fu , Johnston Samuel L. , Southwood Scott , Sette Alessandro , Rosenberg Steven A. 
Published: January 2023

Abstract
Tumor-infiltrating lymphocytes (TILs) derived from tumor-bearing patients recognize tumor-associated Ags presented by MHC class I molecules. The infusion of TIL586 along with IL-2 into the autologous patient with metastatic melanoma resulted in the objective regression of tumor. Two T cell epitopes derived from tumor Ags, tyrosinase-related protein (TRP)-1 and TRP-2, were shown to be recognized by HLA-A31 restricted TIL586 and its T cell clones. In this study we tested the hypothesis that these two peptides can be recognized by CTL from non-HLA-A31 patients with melanoma. It was found that both peptides were capable of binding to HLA-A3, -A11, -A31, -A33, and -A68 of the HLA-A3 supertype. Importantly, we found that HLA-A33-positive TIL1244 and its T cell clones can recognize TRP197–205 presented by both HLA-A31 and -A33 molecules, suggesting that a single TCR can recognize peptide/A31 and peptide/A33 complexes. However, peptide titration experiments showed that the affinity of TCR receptor to peptide/A33 could be higher than that to the peptide/A31. These studies have important implications for the development of peptide-based cancer vaccines.
Prostaglandin E2 Modulation of p59fyn Tyrosine Kinase in T Lymphocytes During Sepsis
Authors: Choudhry Mashkoor A. , Uddin Shahab , Sayeed Mohammed M. 
Published: January 2023

Abstract
Prostaglandin E2 (PGE2) has been implicated in the suppression of T cell IL-2 production and proliferation during burn and sepsis. The present study evaluated the potential intracellular mechanism of suppressed T cell responses by assessing the activation of p59fyn kinase in T cells from septic rats as well as the T cells incubated with PGE2. p59fyn is known to regulate T cell functions. Sepsis was induced in rats by implanting fecal pellets containing Escherichia coli (150 CFU) and Bacteroides fragilis (104 CFU) into the abdominal cavity. For the assessment of PGE2 role in sepsis, a group of septic rats were treated with indomethacin, which inhibits endogenous PGE2 synthesis. As assessed by immunoblotting or in vitro kinase assay, a more than 40% inhibition of p59fyn phosphorylation and kinase activity was observed in septic rat T cells compared with the T cells from sterile or control rats. A similar inhibition in p59fyn phosphorylation and kinase activity was observed in PGE2-treated T cells compared with the T cells incubated in the absence of PGE2. The septic-related suppression in p59fyn phosphorylation and kinase activity in T cells was prevented in rats treated with indomethacin. We observed that the inhibition in p59fyn activation in septic or PGE2-treated T cells was due primarily to a suppression in p59fyn phosphorylation and not due to alterations in p59fyn protein expression. These findings suggest that PGE2 released during sepsis could contribute to the sepsis-related suppression in T cell proliferation by attenuating p59fyn phosphorylation and its kinase activity.
Human Melanoma Patients Recognize an HLA-A1-Restricted CTL Epitope from Tyrosinase Containing Two Cysteine Residues: Implications for Tumor Vaccine Development
Authors: Kittlesen David J. , Thompson Lee W. , Gulden Pamela H. , Skipper Jonathan C. A. , Colella Teresa A. , Shabanowitz Jeffrey A. , Hunt Donald F. , Engelhard Victor H. , Slingluff Craig L. 
Published: January 2023

AbstractTo identify shared epitopes for melanoma-reactive CTL restricted by MHC molecules other than HLA-A*0201, six human melanoma patient CTL lines expressing HLA-A1 were screened for reactivity against the melanocyte differentiation proteins Pmel-17/gp100, MART-1/Melan-A, and tyrosinase, expressed via recombinant vaccinia virus vectors. CTL from five of the six patients recognized epitopes from tyrosinase, and recognition of HLA-A1+ target cells was strongly correlated with tyrosinase expression. Restriction by HLA-A1 was further demonstrated for two of those tyrosinase-reactive CTL lines. Screening of 119 synthetic tyrosinase peptides with the HLA-A1 binding motif demonstrated that nonamer, decamer, and dodecamer peptides containing the sequence KCDICTDEY (residues 243–251) all reconstituted the CTL epitope in vitro. Epitope reconstitution in vitro required high concentrations of these peptides, which was hypothesized to be a result of spontaneous modification of cysteine residues, interfering with MHC binding. Substitution of serine or alanine for the more N-terminal cysteine prevented modification at that residue and permitted target cell sensitization at peptide concentrations 2 to 3 orders of magnitude lower than that required for the wild-type peptide. Because spontaneous modification of sulfhydryl groups may also occur in vivo, tumor vaccines using this or other cysteine-containing peptides may be improved by amino acid substitutions at cysteine residues.
Analysis of the Multiple Interactions Between IL-12 and the High Affinity IL-12 Receptor Complex
Authors: Presky David H. , Minetti Lisa J. , Gillessen Silke , Wilkinson Victoria L. , Wu Chang-You , Gubler Ueli , Chizzonite Richard , Gately Maurice K. 
Published: January 2023

AbstractIL-12 is a heterodimeric cytokine, composed of a p40 and a p35 subunit, that exerts its biological effects by binding to specific cell surface receptors. Two IL-12R proteins, designated human IL-12 (huIL-12) receptor β1 (huIL-12Rβ1) and huIL-12Rβ2, have been previously identified. These IL-12R individually bind huIL-12 with low affinity and in combination bind huIL-12 with high affinity and confer IL-12 responsiveness. In this study the interactions of huIL-12 with these two identified human IL-12R protein subunits are examined. The heterodimer-specific anti-huIL-12 mAb 20C2, which neutralizes huIL-12 bioactivity but does not block 125I-huIL-12 binding to huIL-12Rβ1, blocked binding of huIL-12 to huIL-12Rβ2. In contrast, anti-huIL-12Rβ1 mAb 2B10 and mouse IL-12 p40 subunit homodimer (mo(p40)2) blocked 125I-huIL-12 binding to huIL-12Rβ1, but not to huIL-12Rβ2. Therefore, two classes of IL-12 inhibitors can be identified that differ in their ability to block huIL-12 interaction with either huIL-12Rβ1 or huIL-12Rβ2. Both mo(p40)2 and 20C2 blocked high affinity binding to huIL-12Rβ1/β2-cotransfected COS-7 cells, although, as previously reported, mo(p40)2 does not block high affinity binding to IL-12R on PHA-activated human lymphoblasts. Furthermore, these two classes of IL-12 inhibitors synergistically decreased huIL-12-stimulated proliferation and IFN-γ production. Therefore, IL-12, in binding to the high affinity IL-12R, interacts with IL-12Rβ1 primarily via regions on the IL-12 p40 subunit and with IL-12Rβ2 via 20C2-reactive, heterodimer-specific regions of IL-12 to which the p35 and p40 subunits both contribute.
Maternal Ig Mediates Neonatal Tolerance in Rheumatoid Factor Transgenic Mice but Tolerance Breaks Down in Adult Mice
Authors: Wang Haowei , Shlomchik Mark J. 
Published: January 2023

AbstractWe have recently demonstrated that B cell deletion occurs in the bone marrow of IgHa high affinity anti-IgG2aa (RF) transgenic mice. Here we demonstrate via genetic crosses that the source of IgG2a is the mother, thus establishing a transplacental mechanism that ensures tolerance to developmentally expressed Ags. Since maternal IgG can mediate tolerance in young mice, whether tolerance is maintained or, instead, autoimmunity ensues after weaning was investigated. We find that deletion remits abruptly in these RF transgenic mice beginning at 2 to 3 wk postweaning, and some degree of autoreactivity can be observed thereafter for weeks to months. The mechanism of sustained expression of autoreactive RF B cells in normal mice is unclear as yet, but a plausible mechanism is that once self-reactive cells are present, the antibody they secrete markedly reduces the autoantigen levels, presumably allowing further development, rather than deletion, of newly arising B lineage cells. The phenotype of these RF transgenic mice suggests a positive feedback mechanism that tends to perpetuate autoimmunity once it has been established. If such a mechanism were to exist in autoimmune animals, it could have important implications for the establishment and maintenance of B and T cell tolerance in chronic autoimmune diseases.
Redundancy of C/EBPα, -β, and -δ in Supporting the Lipopolysaccharide-Induced Transcription of IL-6 and Monocyte Chemoattractant Protein-1
Authors: Hu Hsien-Ming , Baer Mark , Williams Simon C. , Johnson Peter F. , Schwartz Richard C. 
Published: January 2023

AbstractC/EBPα, -β, and -δ are members of the CCAAT/enhancer binding protein family of transcriptional regulators. All three of these factors are expressed by bone marrow-derived macrophages, with the DNA binding activity of C/EBPβ and -δ increased by treatment with LPS while that of C/EBPα is decreased. We have ectopically expressed each C/EBP protein in P388 lymphoblasts. The expression of any of these transcription factors is sufficient to confer the LPS-inducible expression of IL-6 and monocyte chemoattractant protein-1 to lymphoblasts, which normally lack C/EBP factors and do not display LPS induction of proinflammatory cytokines. Thus, the activities of C/EBPα, -β, and -δ are redundant in regard to the expression of IL-6 and monocyte chemoattractant protein-1. Since C/EBPβ-deficient mice have been reported to be largely normal in their expression of proinflammatory cytokines, it is likely that the lack of C/EBPβ is compensated for by the induction of C/EBPδ upon LPS treatment.
Induction of CD8+ T Cell Responses to Dominant and Subdominant Epitopes and Protective Immunity to Sendai Virus Infection by DNA Vaccination
Authors: Chen Yongjin , Webster Robert G. , Woodland David L. 
Published: January 2023

AbstractWhile recent studies have demonstrated that DNA vaccination induces potent CD8+ T cell memory in vivo, it is unclear whether this memory is qualitatively and quantitatively comparable with that induced by natural viral infection. In the current studies, we have investigated the induction of CD8+ memory CTL responses to Sendai virus nucleoprotein (NP) in C57BL/6 mice following gene gun vaccination. The data demonstrate that this mode of vaccination induces potent long-lived memory CTL precursors (CTLp) specific for both the dominant (NP324–332/Kb) and the subdominant (NP324–332/Db) epitopes of NP. The frequencies of T cells specific for each of these epitopes in the spleen is about 1:2000 CD8+ T cells, similar to those induced by intranasal infection with Sendai virus. Moreover, the induction of memory CTLp by DNA vaccination is independent of MHC class II molecules or Ab, as is the case for memory CTLp induction by live Sendai virus infection. CTLp specific for both epitopes are capable of migrating to the lung following Sendai virus infection and express potent cytotoxic activity at the site of infection. Consistent with this activity, DNA vaccination with Sendai virus NP induced a substantial degree of Ab-independent protection from a challenge with a lethal dose of Sendai virus. Taken together, these data demonstrate that for the parameters tested, DNA vaccination is indistinguishable from live virus infection in terms of priming functional memory CTLp with broad specificity for both dominant and subdominant T cell epitopes.