bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fine Specificity and MHC Restriction of Trinitrophenyl- Specific CTL
Authors: Franco Alessandra , Yokoyama Takashi , Huynh Dung , Thomson Cole , Nathenson Stanley G. , Grey Howard M. 
Published: January 2023

Abstract
In this study, the fine specificity and MHC restriction of a CTL response specific to the trinitrophenyl (TNP) hapten was analyzed. Based on the structure of peptide/Kb complexes and ternary TCR/Ag/MHC complexes, four TNP peptides, two octamers, and two nonamers were chosen for eliciting anti-TNP CTL responses. Hapten was conjugated at position 4 in the octamers and at position 5 in the nonamers, positions which should allow engagement of the hapten by TCRs. Potent CTL activity for each of the TNP peptides was obtained that was highly hapten-specific; however, there were considerable differences in the extent of cross-reactivity with other TNP peptides, with the octamers generating more cross-reactive CTL than the nonamers. MHC restriction analysis suggested that anti-hapten responses were less dependent on MHC recognition than anti-peptide responses. This was evidenced by the relative ease of detecting cross-reactivity to haptenated peptides presented by allo-MHC and by the relative insensitivity of anti-hapten vs anti-peptide CTL to mutations in the Kb molecule at potential TCR interaction sites. One potential explanation for this insensitivity to MHC mutation was the finding that the anti-hapten response appeared to be of higher avidity, since a &gt;100-fold difference in the amount of Ag required to sensitize target cells was found between these two types of Ags.
Polymerization of IgA and IgM: Roles of Cys309/Cys414 and the Secretory Tailpiece
Authors: Sørensen Vigdis , Sundvold Vibeke , Michaelsen Terje E. , Sandlie Inger 
Published: January 2023

AbstractWe have investigated how the secretory tailpiece (tp), Cys414 and the amino acids flanking Cys414 or Cys309 are involved in regulating the different polymerization of IgM and IgA to pentamers and dimers/monomers, respectively. Whereas changing the tp of IgM to that of IgA has little effect on IgM polymerization, introducing the μtp to IgA leads to the formation of larger than wild-type IgA polymers, including pentamers and hexamer. This shows that the secretory tp can differentially regulate polymerization depending on the heavy chain context. Cys414, which is engaged in intermonomeric disulfide bonds in IgM, is not crucial for the difference in IgM and IgA polymerization; IgM with a C414S mutation forms more large polymers than IgA. Also, IgA with IgM-like mutations in the five amino acids flanking Cys309, which is homologous to Cys414, oligomerize similarly as IgA wild type. Thus, IgA appears to have an inherent tendency to form monomers and dimers that is partially regulated by the tp, while the Cys309 region has only a minor effect. We also show that complement activation by IgM is sensitive to alterations in the polymeric structure, while IgA is inactive in classical complement activation even for polymers such as pentamers and hexamers.
Impaired Fetal Thymocyte Development After Efficient Adenovirus-Mediated Inhibition of NF-κB Activation
Authors: Bakker Talitha R. , Renno Toufic , Jongeneel C. Victor 
Published: January 2023

Abstract
We introduce a new experimental system combining adenovirus-mediated gene transfer and fetal thymic organ culture (FTOC). This system allowed us to efficiently express in developing thymocytes a mutant form of the NF-κB inhibitor IκBα (mut-IκB) and to study the maturation defects occurring when NF-κB activation is inhibited during fetal development. Fetal thymocytes infected with adenovirus containing mut-IκB were found to develop normally until the CD44−CD25+, CD4−CD8− double-negative stage, while production of more mature double-positive and single-positive populations was strongly decreased. Proliferation, as measured by the percentage of cells in cycle appeared normal, as did rearrangement and expression of the TCR β-chain. However, apoptosis was much higher in FTOC infected with adenovirus containing mut-IκB than in FTOC infected with a control virus. Taken together, these results suggest that NF-κB plays a crucial role in ensuring the differentiation and survival of thymocytes in the early stages of their development.
A Conserved Sequence Block in the Murine and Human TCR Jα Region: Assessment of Regulatory Function In Vivo
Authors: Riegert Patricia , Gilfillan Susan 
Published: January 2023

AbstractTemporal control of rearrangement at the TCR α/δ locus is crucial for development of the γδ and αβ T cell lineages. Because the TCR δ locus is embedded within the α locus, rearrangement of any Vα-Jα excises the δ locus, precluding expression of a functional γδ TCR. Approximately 100 kb spanning the Cδ-Cα region has been sequenced from both human and mouse, and comparison has revealed an unexpectedly high degree of conservation between the two. Of interest in terms of regulation, several highly conserved sequence blocks (&gt;90% over &gt;50 bp) were identified that did not correspond to known regulatory elements such as the TCR α and δ enhancers or to coding regions. One of these blocks lying between Jα4 and Jα3, which appears to be conserved in other vertebrates, has been shown to augment TCR α enhancer function in vitro and differentially bind factors from nuclear extracts. To further assess a plausible regulatory role for this element, we have created mice in which this conserved sequence block is either deleted or replaced with a neomycin resistance gene driven by the phosphoglycerate kinase promoter (pgk-neor). Deletion of this conserved sequence block in vivo did have a local effect on Jα usage, echoing the in vitro data. However, its replacement with pgk-neor had a much more dramatic, long range effect, perhaps underscoring the importance of maintaining overall structure at this locus.
Endogenous Glucocorticoids Protect Against Cytokine-Mediated Lethality During Viral Infection
Authors: Ruzek Melanie C. , Pearce Bradley D. , Miller Andrew H. , Biron Christine A. 
Published: January 2023

Abstract
Certain cytokines activate the hypothalamic-pituitary-adrenal axis for glucocorticoid release, and these hormones can protect against cytokine-mediated pathologies. However, endogenous activation of such a pathway has not been established during infections. A prominent glucocorticoid response peaks 36 h following murine CMV (MCMV) infection, coincident with circulating levels of the cytokines IL-12, IFN-γ, TNF, and IL-6, and dependent on IL-6 for maximal release. These studies examined functions of the hormone induction. Mice rendered glucocorticoid deficient by adrenalectomy were more susceptible than intact mice to MCMV-induced lethality, and the increased sensitivity was reversed by hormone replacement. Lack of endogenous glucocorticoids resulted in increases in IL-12, IFN-γ, TNF, and IL-6 production, as well as in mRNA expression for a wider range of cytokines, also including IL-1α and IL-1β. Viral burdens did not increase, and actually decreased, in the livers of glucocorticoid-deficient mice. TNF, but not IFN-γ, was required for increased lethality in the absence of endogenous hormone. These results conclusively demonstrate the importance of induced endogenous glucocorticoids in protection against life-threatening effects resulting from infection-elicited cytokine responses. Taken together with the dependence on induced IL-6, they document existence of an immune system-hypothalamic-pituitary-adrenal axis pathway for regulating endogenous responses to viral infections.
Assessment of Immunogenicity of Human Melan-A Peptide Analogues in HLA-A*0201/Kb Transgenic Mice
Authors: Men Ying , Miconnet Isabelle , Valmori Danila , Rimoldi Donata , Cerottini Jean-Charles , Romero Pedro 
Published: January 2023

AbstractPrevious studies have shown that substitution of single amino acid residues in human Melan-A immunodominant peptides Melan-A27–35 and Melan-A26–35 greatly improved their binding and the stability of peptide/HLA-A*0201 complexes. In particular, one Melan-A peptide analogue was more efficient in the generation of Melan-A peptide-specific and melanoma-reactive CTL than its parental peptide in vitro from human PBL. In this study, we analyzed the in vivo immunogenicity of Melan-A natural peptides and their analogues in HLA-A*0201/Kb transgenic mice. We found that two human Melan-A natural peptides, Melan-A26–35 and Melan-A27–35, were relatively weak immunogens, whereas several Melan-A peptide analogues were potent immunogens for in vivo CTL priming. In addition, induced Melan-A peptide-specific mouse CTL cross-recognized natural Melan-A peptides and their analogues. More interestingly, these mouse CTL were also able to lyse human melanoma cell lines in vitro in a HLA-A*0201-restricted, Melan-A-specific manner. Our results indicate that the HLA-A*0201/Kb transgenic mouse is a useful animal model to perform preclinical testing of potential cancer vaccines, and that Melan-A peptide analogues are attractive candidates for melanoma immunotherapy.
C1qRP Is a Heavily O-Glycosylated Cell Surface Protein Involved in the Regulation of Phagocytic Activity
Authors: Nepomuceno R. R. , Ruiz S. , Park M. , Tenner A. J. 
Published: January 2023

Abstract
C1q, mannose-binding lectin (MBL), and pulmonary surfactant protein A (SPA) interact with human monocytes and macrophages, resulting in the enhancement of phagocytosis of suboptimally opsonized targets. mAbs that recognize a cell surface molecule of 126,000 Mr, designated C1qRP, have been shown to inhibit C1q- and MBL-mediated enhancement of phagocytosis. Similar inhibition of the SPA-mediated enhancement of phagocytosis by these mAbs now suggests that C1qRP is a common component of a receptor for these macromolecules. Ligation of human monocytes with immobilized R3, a IgM mAb recognizing C1qRP, also triggers enhanced phagocytic capacity of these cells in the absence of ligand, verifying the direct involvement of this polypeptide in the regulation of phagocytosis. While the cDNA for C1qRP encodes a 631 amino acid membrane protein, Chinese hamster ovary cells transfected with the cDNA of the C1qRP coding region express a surface glycoprotein with the identical 126,000 Mr in SDS-PAGE as the native C1qRP. Use of glycosylation inhibitors, cleavage of the mature C1qRP with specific glycosidases, and in vitro translation of C1qRP cDNA demonstrated that both posttranslational glycosylation and the nature of the amino acid sequence of the protein contribute to the difference between its predicted m.w. and its migration on SDS-PAGE. These results verify that the cDNA cloned codes for the mature C1qRP, that C1qRP contains a relatively high degree of O-linked glycoslyation, and that C1qRP cross-linked directly by monoclonal anti-C1qRP or engaged as a result of cell surface ligation of SPA, as well as C1q and MBL, enhances phagocytosis.
Modulation of Formyl Peptide Receptor Expression by IL-10 in Human Monocytes and Neutrophils
Authors: Thivierge Maryse , Parent Jean-Luc , Stankova Jana , Rola-Pleszczynski Marek 
Published: January 2023

AbstractIL-10, originally described as a cytokine synthesis inhibitory factor, is secreted by a number of cells of the immune system, including monocytes and T cells. Although IL-10 is being assigned as an immunosuppressive cytokine, our study showed that FMLP-R mRNA was rapidly up-regulated by exposure of monocytes to graded concentrations of this cytokine, with maximal (three- to fourfold) stimulation with 10 ng/ml. The effect was rapid, being observable as early as 1 h of treatment with IL-10, maximal between 2 and 4 h, and still evident after 24 h and was associated with an increase of receptor expression on the cell surface as assessed by flow cytometry analysis. Pretreatment of monocytes with actinomycin D completely abrogated the effect of IL-10, suggesting a transcriptional regulation. Moreover, IL-10-treated monocytes showed a significantly enhanced functional responsiveness to FMLP with enhanced (three- to fourfold) chemotaxis and augmented (twofold) intracellular calcium mobilization. In polymorphonuclear neutrophils (PMN), IL-10 also mediated a twofold augmentation of FMLP-R expression. In parallel experiments, we observed that IL-10 could differentially modulate other chemotactic receptors. Hence, we observed that IL-10 augmented two- to threefold platelet-activating factor receptor (PAF-R) expression, whereas it had no significant effect on the fifth component of complement (C5a) receptor (C5a-R) expression. Collectively, our results demonstrate that IL-10 may play an important role in inflammatory processes through modulation of chemotactic receptor expression.
EBV Gene Expression Not Altered in Rheumatoid Synovia Despite the Presence of EBV Antigen-Specific T Cell Clones
Authors: Edinger James W. , Bonneville Marc , Scotet Emmanuel , Houssaint Elisabeth , Schumacher H. Ralph , Posnett David N. 
Published: January 2023

Abstract
T cells infiltrating the rheumatoid arthritis (RA) joint are oligoclonal, implicating an Ag-driven process, but the putative joint-specific Ags remain elusive. Here we examine expression of selected EBV genes in RA synovia and find no abnormal expression in RA. DNA of CMV and EBV was detectable by PCR in the synovial tissue of RA. RNA of several latent and lytic EBV genes was also detectable. However, there were no differences in EBV gene expression in synovial tissues or peripheral blood when comparing RA with osteoarthritis, Gulf War syndrome, and other disease controls. RA synovia with highly expanded CD8 T cell clones reactive with defined EBV peptide Ags presented by HLA class I alleles lacked evidence of abnormal mRNA expression for the relevant EBV Ag (BZLF1) or lacked amplifiable mRNA (BMLF1). Thus, local production of EBV Ags in synovial tissues may not be the cause of the accumulation of T cell clones specific for these Ags. Instead, APCs loaded with processed EBV peptides may migrate to the synovium. Alternatively, EBV-specific T cell clones may be generated in other tissues and then migrate to synovia, perhaps due to cross-reactive joint-specific Ags or because of expression of homing receptors.
Differential Effects of CD40 Ligand/Trimer Stimulation on the Ability of Dendritic Cells to Replicate and Transmit HIV Infection: Evidence for CC-Chemokine-Dependent and -Independent Mechanisms
Authors: McDyer John F. , Dybul Mark , Goletz Theresa J. , Kinter Audrey L. , Thomas Elaine K. , Berzofsky Jay A. , Fauci Anthony S. , Seder Robert A. 
Published: January 2023

Abstract
The role of exogenous stimulation of CD40 by CD40 ligand (CD40L) in dendritic cell (DC) maturation, CC-chemokine production, and CCR5 receptor expression was examined using a soluble trimeric CD40L agonist protein (CD40LT). Stimulation of monocyte-derived DCs with CD40LT enhanced the production of the CC-chemokines macrophage inflammatory protein (MIP)-1α, MIP-1β, and RANTES and diminished surface expression of CCR5. Based on these findings, the functional role of CD40LT stimulation on the ability of DCs to replicate and transmit HIV viral infection was studied. The addition of CD40LT to cocultures of naive CD4+ T cells and autologous DCs (T/DC) infected with the macrophage-tropic isolate, HIVBaL, caused a striking reduction in reverse transcriptase (RT) activity after 10 and 14 days of culture. The addition of a mixture of Abs against CC-chemokines abrogated the decrease in RT activity, demonstrating that the inhibitory effect mediated by CD40LT was CC-chemokine-dependent. In contrast, the presence of CD40LT in T/DC cocultures infected with the T cell-tropic isolate, HIVIIIB, caused an increase in RT activity that was CC-chemokine-independent. Of note, CD40LT stimulation also inhibited RT activity in cultures containing macrophage-tropic virus (HIVBaL)-infected DC only. However, in contrast to the results seen in the T/DC cocultures, CD40LT stimulation inhibited RT activity in cultures of DCs alone in a CC-chemokine-independent manner. Together, these results show that CD40LT stimulation of DCs suppresses HIV replication and transmission to CD4+ T cells by two potentially different mechanisms.
Molecular and Functional Analysis of a Conserved CTL Epitope in HIV-1 p24 Recognized from a Long-Term Nonprogressor: Constraints on Immune Escape Associated with Targeting a Sequence Essential for Viral Replication
Authors: Wagner Ralf , Leschonsky Bernd , Harrer Ellen , Paulus Christina , Weber Christine , Walker Bruce D. , Buchbinder Susan , Wolf Hans , Kalden Joachim R. , Harrer Thomas 
Published: January 2023

AbstractIt has been hypothesized that sequence variation within CTL epitopes leading to immune escape plays a role in the progression of HIV-1 infection. Only very limited data exist that address the influence of biologic characteristics of CTL epitopes on the emergence of immune escape variants and the efficiency of suppression of HIV-1 by CTL. In this report, we studied the effects of HIV-1 CTL epitope sequence variation on HIV-1 replication. The highly conserved HLA-B14-restricted CTL epitope DRFYKTLRAE in HIV-1 p24 was examined, which had been defined as the immunodominant CTL epitope in a long-term nonprogressing individual. We generated a set of viral mutants on an HX10 background differing by a single conservative or nonconservative amino acid substitution at each of the P1 to P9 amino acid residues of the epitope. All of the nonconservative amino acid substitutions abolished viral infectivity and only 5 of 10 conservative changes yielded replication-competent virus. Recognition of these epitope sequence variants by CTL was tested using synthetic peptides. All mutations that abrogated CTL recognition strongly impaired viral replication, and all replication-competent viral variants were recognized by CTL, although some variants with a lower efficiency. Our data indicate that this CTL epitope is located within a viral sequence essential for viral replication. Targeting CTL epitopes within functionally important regions of the HIV-1 genome could limit the chance of immune evasion.
Cutting Edge: Toll-Like Receptor 4 (TLR4)-Deficient Mice Are Hyporesponsive to Lipopolysaccharide: Evidence for TLR4 as the Lps Gene Product
Authors: Hoshino Katsuaki , Takeuchi Osamu , Kawai Taro , Sanjo Hideki , Ogawa Tomohiko , Takeda Yoshifumi , Takeda Kiyoshi , Akira Shizuo 
Published: January 2023

Abstract
The human homologue of Drosophila Toll (hToll), also called Toll-like receptor 4 (TLR4), is a recently cloned receptor of the IL-1/Toll receptor family. Interestingly, the TLR4 gene has been localized to the same region to which the Lps locus (endotoxin unresponsive gene locus) is mapped. To examine the role of TLR4 in LPS responsiveness, we have generated mice lacking TLR4. Macrophages and B cells from TLR4-deficient mice did not respond to LPS. All these manifestations were quite similar to those of LPS-hyporesponsive C3H/HeJ mice. Furthermore, C3H/HeJ mice have, in the cytoplasmic portion of TLR4, a single point mutation of the amino acid that is highly conserved among the IL-1/Toll receptor family. Overexpression of wild-type TLR4 but not the mutant TLR4 from C3H/HeJ mice activated NF-κB. Taken together, the present study demonstrates that TLR4 is the gene product that regulates LPS response.
Cutting Edge: Species Specificity of the CC Chemokine 6Ckine Signaling Through the CXC Chemokine Receptor CXCR3: Human 6Ckine Is Not A Ligand for the Human or Mouse CXCR3 Receptors
Authors: Jenh Chung-Her , Cox Mary Ann , Kaminski Heather , Zhang Meng , Byrnes Heather , Fine Jay , Lundell Daniel , Chou Chuan-Chu , Narula Satwant K. , Zavodny Paul J. 
Published: January 2023

Abstract
The CC chemokine known as 6Ckine (SLC, Exodus-2, or TCA4) has been identified as a ligand for CCR7. Mouse 6Ckine has also been shown to signal through mouse CXCR3 and share some of the activities of IFN-γ inducible protein 10 and monokine induced by IFN-γ. Nonetheless, human 6Ckine has not been shown to bind CXCR3 receptor or have angiostatic activity. In this study, we report that human 6Ckine does not induce a calcium flux in either human CXCR3 or mouse CXCR3 transfected cells, although it is an equally potent agonist as mouse 6Ckine and human macrophage inflammatory protein-3β in human CCR7 transfected cells. Mouse 6Ckine (but not human 6Ckine) is capable of competing with radiolabeled IFN-γ inducible protein 10 for human CXCR3. In addition, radiolabeled human 6Ckine does not bind to either human CXCR3 or mouse CXCR3. Together these data suggest that human CC chemokine 6Ckine is not a ligand for the human or mouse CXC chemokine receptor CXCR3.
Mice with IFN-γ Receptor Deficiency Are Less Susceptible to Experimental Autoimmune Myasthenia Gravis
Authors: Zhang Guang-Xian , Xiao Bao-Guo , Bai Xue-Feng , van der Meide Peter H. , Örn Anders , Link Hans 
Published: January 2023

Abstract
IFN-γ can either adversely or beneficially affect certain experimental autoimmune diseases. To study the role of IFN-γ in the autoantibody-mediated experimental autoimmune myasthenia gravis (EAMG), an animal model of myasthenia gravis in humans, IFN-γR-deficient (IFN-γR−/−) mutant C57BL/6 mice and congenic wild-type mice were immunized with Torpedo acetylcholine receptor (AChR) plus CFA. IFN-γR−/− mice exhibited significantly lower incidence and severity of muscle weakness, lower anti-AChR IgG Ab levels, and lower Ab affinity to AChR compared with wild-type mice. Passive transfer of serum from IFN-γR−/− mice induced less muscular weakness compared with serum from wild-type mice. In contrast, numbers of lymph node cells secreting IFN-γ and of those expressing IFN-γ mRNA were strongly augmented in the IFN-γR−/− mice, reflecting a failure of negative feedback circuits. Cytokine studies by in situ hybridization revealed lower levels of lymphoid cells expressing AChR-reactive IL-1β and TNF-α mRNA in AChR + CFA-immunized IFN-γR−/− mice compared with wild-type mice. No differences were found for AChR-reactive cells expressing IL-4, IL-10, or TGF-β mRNA. These results indicate that IFN-γ promotes systemic humoral responses in EAMG by up-regulating the production and the affinity of anti-AChR autoantibodies, thereby contributing to susceptibility to EAMG in C57BL/6-type mice.
Chemokine Receptor Responses on T Cells Are Achieved Through Regulation of Both Receptor Expression and Signaling
Authors: Rabin Ronald L. , Park Matthew K. , Liao Fang , Swofford Ruth , Stephany David , Farber Joshua M. 
Published: January 2023

AbstractTo address the issues of redundancy and specificity of chemokines and their receptors in lymphocyte biology, we investigated the expression of CC chemokine receptors CCR1, CCR2, CCR3, CCR5, CXCR3, and CXCR4 and responses to their ligands on memory and naive, CD4 and CD8 human T cells, both freshly isolated and after short term activation in vitro. Activation through CD3 for 3 days had the most dramatic effects on the expression of CXCR3, which was up-regulated and functional on all T cell populations including naive CD4 cells. In contrast, the effects of short term activation on expression of other chemokine receptors was modest, and expression of CCR2, CCR3, and CCR5 on CD4 cells was restricted to memory subsets. In general, patterns of chemotaxis in the resting cells and calcium responses in the activated cells corresponded to the patterns of receptor expression among T cell subsets. In contrast, the pattern of calcium signaling among subsets of freshly isolated cells did not show a simple correlation with receptor expression, so the propensity to produce a global rise in the intracellular calcium concentration differed among the various receptors within a given T cell subset and for an individual receptor depending on the cell where it was expressed. Our data suggest that individual chemokine receptors and their ligands function on T cells at different stages of T cell activation/differentiation, with CXCR3 of particular importance on newly activated cells, and demonstrate T cell subset-specific and activation state-specific responses to chemokines that are achieved by regulating receptor signaling as well as receptor expression.