bluuebunny/crossref_metadata_2025_split huggingface dataset:
IFN-γ Is Critical for Long-Term Allograft Survival Induced by Blocking the CD28 and CD40 Ligand T Cell Costimulation Pathways
Authors: Konieczny Bogumila T. , Dai Zhenhua , Elwood Eric T. , Saleem Sohail , Linsley Peter S. , Baddoura Fady K. , Larsen Christian P. , Pearson Thomas C. , Lakkis Fadi G. 
Published: January 2023

AbstractIt is postulated that IFN-γ production hinders long-term acceptance of transplanted organs. To test this hypothesis, we compared survival of skin and heart allografts in wild-type (IFN-γ+/+) mice to that in IFN-γ gene knockout (IFN-γ−/−) mice. We found that perioperative blockade of the CD28 and/or CD40 ligand T cell costimulation pathways induces long-term skin and heart allograft survival in IFN-γ+/+ recipients but fails to do so in IFN-γ−/− mice or in wild-type mice treated with IFN-γ-neutralizing Ab at the time of transplantation. In vitro studies showed that endogenously produced IFN-γ down-regulates T cell proliferation and CTL generation in MLCs. These actions of IFN-γ were not mediated by TNF-α production or Fas-Fas ligand interactions. In vivo studies revealed exaggerated expansion and, subsequently, impaired deletion of superantigen-reactive T lymphocytes in IFN-γ−/− mice injected with staphylococcal enterotoxin B. Taken together, our findings indicate that IFN-γ does not hinder but instead facilitates induction of long-term allograft survival possibly by limiting expansion of activated T cells.
Requirement for Jak3 in Mature T Cells: Its Role in Regulation of T Cell Homeostasis
Authors: Sohn Sue J. , Forbush Katherine A. , Nguyen Nhan , Witthuhn Bruce , Nosaka Tetsuya , Ihle James N. , Perlmutter Roger M. 
Published: January 2023

Abstract
The tyrosine kinase Jak3 plays a key role in transducing signals from the IL-2, -4, -7, -9, and -15 receptors. Mice lacking Jak3 exhibit a profound, early block in both B and T cell development. To examine the mechanisms whereby Jak3 influences T cell function, we have reconstituted thymic development in Jak3−/− animals by introducing a Jak3 transgene in which expression was driven by the lck proximal promoter. Thymic reconstitution required Jak3 kinase activity, as catalytically inactive Jak3 did not restore early thymic development. Furthermore, the thymus-restricted expression pattern of the transgene allowed us to assess the requirement for Jak3 in peripheral T cells. In these mice, loss of Jak3 expression was associated with a failure to proliferate in response to antigen receptor crosslinking, the accumulation of T cells manifesting an activated cell surface phenotype, and an increased CD4/CD8 ratio among peripheral T cells, all of which are characteristics that were observed in Jak3−/− animals. Finally, we present data which suggest that peripheral T cells proliferate more rapidly in vivo and also undergo apoptosis more rapidly, upon loss of Jak3. Hence Jak3 exerts effects on mature peripheral T lymphocytes, as well as on thymocytes, resulting in the proper maintenance of circulating, quiescent cells.
A Mucosal Intranet: Intestinal Epithelial Cells Down-Regulate Intraepithelial, But Not Peripheral, T Lymphocytes
Authors: Yamamoto Masafumi , Fujihashi Kohtaro , Kawabata Keiko , McGhee Jerry R. , Kiyono Hiroshi 
Published: January 2023

Abstract
Epithelial cells and lymphocytes, including γδ and αβ T cells, in the gastrointestinal tract epithelium represent a major host defense intranet that is incompletely understood. Cell-to-cell interactions between intraepithelial lymphocytes (IELs) and intestinal epithelial cells (IECs) comprise this intranet, and we have assessed the role of IECs in the regulation of γδ and αβ T cell responses. When highly purified CD3+ IEL T cells were stimulated via the TCR-CD3 complex, high proliferative responses and cytokine synthesis were induced. However, the addition of viable IECs or purified IEC membranes (mIEC) down-regulated T cell proliferative and cytokine responses. Further, the inhibitory effect of mIEC was not restored by antibodies to TGF-β, CD1d, E-cadherin, or MHC class I or II. This inhibitory effect was noted for both γδ and αβ T cell subsets from IELs, and mRNA levels were reduced for both Th1 (IL-2 and IFN-γ) and Th2 (IL-4 and IL-5) cytokines in γδ and αβ IELs. In contrast, a purified membrane fraction obtained from thymocytes did not inhibit IEL proliferative responses. Further, mIEC did not inhibit splenic αβ T cell proliferative responses. These findings show that cell-to-cell interactions between intraepithelial γδ and αβ T cells and IECs occur via cell surface molecules, suggesting an intranet to prevent potential inflammatory responses at the intestinal mucosal surface.
Different Protein Kinase C Isoenzymes Regulate IL-2 Receptor Expression or IL-2 Synthesis in Human Lymphocytes Stimulated via the TCR
Authors: Szamel Marta , Appel Annette , Schwinzer Reinhard , Resch Klaus 
Published: January 2023

AbstractStimulation of purified human PBL with mAbs raised against the T cell receptor resulted in an immediate and transient activation of protein kinase C-α (PKC-α) and PKC-θ, peaking at 10 min, whereas PKC-β, -δ, and -ε were translocated with a delay of &gt;90 min and remained activated for up to 2 h. To characterize specific functions of distinct PKC isoenzymes, Abs against different PKC isoenzymes were introduced by means of electropermeabilization. Neutralization of PKC-α and -θ resulted in the complete inhibition of IL-2R expression, whereas anti-PKC-β, -δ, and -ε Abs inhibited IL-2 synthesis. Extensive control experiments have shown that neither electropermeabilization nor control Ig influenced PKC activity and cellular functions. Our data thus clearly show that specific PKC isoenzymes regulate different cellular functions in stimulated human lymphocytes.
Inhibition of Cell Cycle Progression by a Synthetic Peptide Corresponding to Residues 65–79 of an HLA Class II Sequence: Functional Similarities but Mechanistic Differences with the Immunosuppressive Drug Rapamycin
Authors: Boytim Michelle L. , Lyu Shu-Chen , Jung Ron , Krensky Alan M. , Clayberger Carol 
Published: January 2023

Abstract
A synthetic peptide corresponding to a region of the α1 α-helix of DQA03011 (DQ 65–79) inhibits the proliferation of human PBL and T cells in an allele-nonspecific manner. It blocks proliferation stimulated by anti-CD3 mAb, PHA-P, and alloantigen, but not by PMA and ionomycin. Substitution of each amino acid with serine shows that residues 66, 68, 69, 71–73, and 75–79 are critical for function. Inhibition of proliferation is long lasting and is not reversible with exogenous IL-2. The peptide can be added 24 to 48 h after stimulation and still block proliferation. The DQ 65–79 peptide does not affect expression of IL-2 or IL-2R; however, IL-2-stimulated proliferation is inhibited. Cell cycle progression is blocked at the G1/S transition, and the activity of cdk2 (cyclin-dependent kinase 2) kinase is impaired by the continued presence of p27. Although these results suggest a mechanism similar to that of rapamycin, the peptide inhibition is not reversed with FK-506, which indicates a distinct mechanism.
CD38 Functions Are Regulated Through an Internalization Step
Authors: Funaro Ada , Reiniš Milan , Trubiani Oriana , Santi Spartaco , Di Primio Roberto , Malavasi Fabio 
Published: January 2023

AbstractThe endocytosis of the human CD38 molecule has been investigated in normal lymphocytes and in a number of leukemia- and lymphoma-derived cell lines. CD38 internalization was followed using radioiodinated Abs in an acidic elution endocytosis assay to monitor the effects of cross-linking on internalization processes and to quantify the ratio of the internalized molecule. Second, conventional, confocal, and electron microscopies were used to evaluate the morphologic effects induced by ligation of the molecule with Abs mimicking the natural ligand(s). The results demonstrated that internalization is a reproducible phenomenon following CD38 ligation with both agonistic and nonagonistic specific Abs and involving only a fraction of the entire amount of the surface molecule. It is independent from signal transduction as can be inferred by the observation that 1) both agonistic and non agonistic Abs are effective and 2) the dynamic of internalization is much slower than that of cellular signaling. Morphologic studies demonstrated that endocytosis induced as a result of CD38 ligation presents a very specific pathway consisting of subcellular organelles fundamental to the processing of the complex. Our data indicate that down-regulation by endocytosis may be, in parallel with shedding, a regulatory element in activation and adhesion processes mediated by CD38. However, internalization seems not to be a key step in triggering intracellular signaling; more likely, it is a negative feedback control mechanism which interrupts signal transduction or cell-cell cross-talks mediated by membrane CD38.
PU.1/Spi-1 Is Essential for the B Cell-Specific Activity of the Mouse CD72 Promoter
Authors: Ying Han , Chang Ju-Fay , Parnes Jane R. 
Published: January 2023

AbstractCD72 is a 45-kDa glycoprotein that is predominantly expressed on cells of the B lineage, except for plasma cells. Its expression pattern is representative of many B cell-specific proteins, which are essential for B cell development and activation but are down-regulated after B cells become terminally differentiated plasma cells. We have examined the promoter region of the mouse CD72 gene to identify sequences responsible for this regulatory pattern. The CD72 gene does not have an obvious TATAA box. Primer extension assays identified multiple transcription initiation sites. Deletion analyses have identified the 255-bp minimal promoter required for tissue-specific and developmental stage-specific expression. DNase I footprinting analysis of the CD72 minimal promoter revealed three protected elements: FP I, FP II, and FP III. Sequences corresponding to FP I or III gave increased reporter gene activity specifically in B cells, but not in T cells or NIH-3T3 cells. Sequences corresponding to FP II gave increased reporter gene activity in mature B cells, but not in plasma cells or non-B cells. Electrophoretic mobility shift assays and DNase I protection analyses revealed that FP I was bound by the transcription factor PU.1/Spi-1. Transient reporter analyses with plasmid bearing the mutated PU.1 binding site showed that binding of PU.1 is necessary for the increase in CD72 promoter activity in B cells. These results suggest that the 255-bp CD72 promoter confers both tissue specificity and developmental stage specificity, and that the B cell and macrophage-specific transcription factor PU.1 is essential for regulating the tissue specificity of the mouse CD72 promoter.
Analysis of BR96 Binding Sites for Antigen and Anti-Idiotype by Codon-Based Scanning Mutagenesis
Authors: Rosok Mae Joanne , Eghtedarzadeh-Kondri Mohammad , Young Kelly , Bajorath Jürgen , Glaser Scott , Yelton Dale 
Published: January 2023

AbstractWe performed a scanning mutagenesis study of heavy chain complementarity-determining region (CDR) residues to identify how mutations affected binding of the anti-carcinoma mAb BR96 to Ag, Lewis Y, and to an anti-Id Ab (anti-Id). By ELISA, we demonstrated that the anti-Id bound close to the Ag binding site of BR96, but the anti-Id and Ag sites were not identical. Immunoblot analysis and screening of light and heavy chain CDR libraries with multiple mutations in each CDR suggested that the heavy chain had greater involvement in anti-Id binding. We then analyzed contributions of individual residues in the heavy chain CDRs to binding of Ag and anti-Id. In a filamentous phage vector containing BR96 V region sequences, mutations were introduced by codon-based mutagenesis at single positions within the three heavy chain CDRs. The resulting libraries of Fab fragments had all amino acids represented at a CDR position. We evaluated the expressed Fabs for binding to Ag and anti-Id by plaque lift assay. We identified the positions with mutations that had the greatest negative effect on binding to the anti-Id and to Ag and analyzed them on the basis of the BR96 x-ray structure. The residues most important for binding to the anti-Id were located in heavy chain CDR1 and CDR2 and were peripheral to the residues within the Lewis Y binding pocket.
Base-Specific Sequences That Bias Somatic Hypermutation Deduced by Analysis of Out-of-Frame Human IgVH Genes
Authors: Dunn-Walters Deborah K. , Dogan Ahmet , Boursier Laurent , MacDonald Connie M. , Spencer Jo 
Published: January 2023

AbstractSomatic hypermutation introduces mutations into IgV genes during affinity maturation of the B cell response. Mutations are introduced nonrandomly, and are generally targeted to the complementarity determining regions (CDRs). Subsequent selection against mutations that result in lower affinity or nonfunctional Ig increases the relative number of mutations in the CDRs. Investigation of somatic hypermutation is hampered by the effects of selection. We have avoided this by studying out-of-frame human IgVH4.21 and 251 genes, which, being unused alleles, are unselected. By comparison of the frequency of A, C, G, and T nucleotides at positions −3 to +3 around mutated or unmutated A, C, and G nucleotides, we have identified flanking sequences that most commonly surround mutated bases. Distinct trends in flanking sequences that were unique for each base were observed. Statistically significant trends that were common to both IgVH4.21 and 251 were used to deduce motifs that bias somatic hypermutation. The motifs deduced from this data, with targeted bases in regular type, are AANB, WDCH, and DGHD (where W = A/T, B = C/G/T, D = A/G/T, H = A/C/T, and N = any base). Mutations from C and G in two further groups of out-of-frame human IgVH genes, not used in the deduction of the motifs, occurred significantly within the motifs for C and G. The proposed target sequence for G is within the reverse complement of the target sequence for C, suggesting that the hypermutation mechanism may target only G or C. The mutation in the complementary base would appear on the other strand following replication.
A Peptide Binding Motif for HLA-DQA1*0102/DQB1*0602, the Class II MHC Molecule Associated with Dominant Protection in Insulin-Dependent Diabetes Mellitus
Authors: Ettinger Ruth A. , Kwok William W. 
Published: January 2023

AbstractHLA-DQA1*0102/DQB1*0602 (DQ0602) is observed at a decreased frequency in insulin-dependent diabetes mellitus in different ethnic groups, suggesting a protective role for DQ0602. Analysis of overlapping peptides from human insulin found that insulin B(1–15) bound well to DQ0602 and exhibited a high degree of allelic specificity. Truncation analysis of insulin B(1–15) identified insulin B(5–15) as the minimal peptide for DQ0602 binding. Insulin B(5–15) bound to DQ0602 with an apparent KD of 0.7 to 1.0 μM and peptide binding reached equilibrium at 96 h. Single arginine substitutions at each position of the insulin B(5–15) peptide identified amino acids 6, 8, 9, 11, and 14 (relative positions P1, P3, P4, P6, and P9) as important for binding. Extensive substitutions for each of these amino acids revealed that amino acids 11 and 14 (P6 and P9) exhibited the highest specificity. Amino acid 11 (P6) preferred large aliphatic amino acids, while amino acid 14 (P9) preferred smaller aliphatic and hydroxyl amino acids. Binding of an overlapping series of peptides from a randomly chosen protein, the herpes simplex virus-2 tegument protein UL49, correlated completely with the presence or absence of the DQ0602 peptide binding motif. Peptides 11 amino acids long were selected from GAD65, IA-2, and proinsulin, that contained the DQ0602 peptide binding motif. Of these, 79% (19 of 24) were able to bind DQ0602. This study identifies a peptide binding motif for DQ0602 and peptides from insulin-dependent diabetes mellitus autoantigens that bind DQ0602 in vitro.
Type 1- and Type 2-Like Lesional Skin-DerivedMycobacterium leprae-Responsive T Cell Clones Are Characterized by Coexpression of IFN-γ/TNF-α and IL-4/IL-5/IL-13, Respectively
Authors: Verhagen Claudia E. , van der Pouw Kraan Tineke C. T. M. , Buffing Anita A. M. , Chand Mohamed A. , Faber William R. , Aarden Lucien A. , Das Pranab K. 
Published: January 2023

AbstractIn an earlier study, we generated a large number of Mycobacterium leprae-responsive and M. leprae-nonresponsive T cell clones (TCC) from the lesional skin of immunologic unstable borderline leprosy patients. In that study, we divided TCC into type 1- and type 2-like on the basis of their IFN-γ and IL-4 expression. To explore whether other cytokines are coproduced along with IFN-γ and IL-4, we investigated the secretion of a panel of other cytokines (TNF-α, IL-5, IL-6, IL-10, and IL-13) by a large number of these TCC. Upon analysis of 139 M. leprae-responsive TCC, we observed a positive correlation in the coproduction of IFN-γ/TNF-α (r = 0.81), and in that of IL-4/IL-5 (r = 0.83), IL-4/IL-13 (r = 0.80), and IL-5/IL-13 (r = 0.82). Polarized type 1-like TCC produced dominantly IFN-γ/TNF-α, and polarized type 2-like TCC predominantly IL-4/IL-5/IL-13. Most type 0-like TCC produced both sets of cytokines. In contrast, type 1- and type 2-like subsets of M. leprae-nonresponsive TCC (n = 58) did not show the same coexpression of these cytokines. Furthermore, when the differential expression of a broad panel of cytokines by individual M. leprae-responsive TCC is considered, it appeared that additional phenotypes could be recognized. These results suggested that distinct isotypes of type 1- and type 2-like T cells, based on the secretion of a panel of cytokines, may reflect M. leprae-specific characteristics.
IL-5 Is Required for Eosinophil Recruitment, Crystal Deposition, and Mononuclear Cell Recruitment During a Pulmonary Cryptococcus neoformans Infection in Genetically Susceptible Mice (C57BL/6)
Authors: Huffnagle Gary B. , Boyd Michael B. , Street Nancy E. , Lipscomb Mary F. 
Published: January 2023

Abstract
CBA/J (highly resistant), BALB/c (moderately resistant), and C57BL/6 (susceptible) mice displayed three resistance patterns following intratracheal inoculation of Cryptococcus neoformans 52. The inability to clear the infection correlated with the duration of the eosinophil infiltrate in the lungs. The role of IL-5 in promoting the pulmonary eosinophilia and subsequent inflammatory damage in susceptible C57BL/6 mice was investigated. C57BL/6 mice developed a chronic alveolar, peribronchiolar, and perivascular eosinophilia following C. neoformans infection. This resulted in the accumulation of intracellular Charcot-Leyden-like crystals in alveolar macrophages by wk 4 and the extracellular deposition of these crystals in the bronchioles with associated destruction of airway epithelium by wk 6. IL-5 mRNA was expressed in the lungs, and injections of anti-IL-5 mAb prevented eosinophil recruitment and crystal deposition but did not alter cryptococcal clearance. Depletion of CD4+ T cells (but not CD8+) ablated IL-5 production by lung leukocytes in vitro and eosinophil recruitment in vivo. Neutralization of IL-5 also inhibited the recruitment of macrophages, CD8+ T lymphocytes, and B lymphocytes by 47 to 57%. Anti-IL-5 mAb inhibited CD4+ T lymphocyte recruitment by 30% but did not affect neutrophil recruitment. Thus, the development of a chronic eosinophil infiltrate in the lungs of C. neoformans-infected C57BL/6 mice is a nonprotective immune response that causes significant lung pathology. Furthermore, IL-5 promotes the recruitment and activation of eosinophils, resulting in the recruitment of additional macrophages and lymphocytes into the lungs.
Lymphocyte-Dependent Inhibition of Growth of VirulentMycobacterium tuberculosisH37Rv Within Human Monocytes: Requirement for CD4+ T Cells in Purified Protein Derivative-Positive, But Not in Purified Protein Derivative-Negative Subjects
Authors: Silver Richard F. , Li Qing , Boom W. Henry , Ellner Jerrold J. 
Published: January 2023

AbstractProtective human immunity to Mycobacterium tuberculosis(M. tb) has proven difficult to characterize, in part because of technical obstacles to in vitro infection of human cells with virulent M. tb. We established a reproducible method of infecting human monocytes (MN) with the virulent M. tb strain H37Rv that did not reduce MN viability. TNF-α had no effect on replication of H37Rv within MN, and IFN-γ mediated only a 1.9-fold reduction in bacterial growth. In contrast, nonadherent cells (NAC) from purified protein derivative (PPD)-positive and PPD-negative subjects reduced intracellular growth of H37Rv by 6- and 10.6-fold, respectively (p = 0.007 and p = 0.005). CD4+ T cells were essential to growth inhibition mediated by NAC of PPD-positive subjects, whereas containment of M. tb by NAC of PPD-negative subjects did not require CD4+ cells. CD8+ T cells did not contribute to protection mediated by NAC of either group. Supernatants of cocultured H37Rv-infected MN and NAC only partially reduced intracellular growth of M. tb despite containing nanogram concentrations of TNF-α and IFN-γ. Neutralizing antibodies to TNF-α, IFN-γ, and IL-12 failed to affect the NAC-mediated growth limitation. NAC treated with emetine retained approximately 40% of their capacity to contain intracellular H37Rv, however. These studies indicate that protective human recall responses to M. tb are mediated primarily by CD4+ T cells, whereas CD4−CD8− lymphocytes may contribute to innate immunity to M. tb. The ability of NAC to activate M. tb-infected MN is only partly attributable to soluble mediators and may also involve contact-mediated mechanisms.
Development of a Murine Mutant Ras CD8+ CTL Peptide Epitope Variant That Possesses Enhanced MHC Class I Binding and Immunogenic Properties
Authors: Bristol J. Andrew , Schlom Jeffrey , Abrams Scott I. 
Published: January 2023

AbstractWe recently identified a murine mutant Ras p21 CD8+ CTL epitope reflecting residues 4 to 12, containing the mutation of Gly to Val at codon 12, that bound weakly to H-2Kd in vitro and generated a weak primary CTL response in immunized BALB/c mice. Here, we explored the hypothesis that specific modifications to the Ras4–12 peptide sequence can improve MHC binding, leading to enhanced immunogenicity without altering immune specificity. We synthesized Ras4–12 peptides in which Val at residue 12 was replaced with the more dominant H-2Kd C-terminus anchor residue Leu or Ile. In functional H-2Kd binding assays, Ras4–12(L12 or I12) peptide variants competed more effectively than the Ras4–12(V12) peptide. Ras4–12(L12 or I12) peptide variants enhanced both in vitro cytotoxicity and proliferation responses of anti-Ras4–12 CTL compared with the mutant Ras4–12(V12) peptide. Additionally, the Ras4–12(L12) peptide variant induced a quantitatively greater T cell response in vivo compared with that produced by Ras4–12(V12) as determined by IFN-γ production. Mice immunized with Ras4–12(L12) peptide elicited CD8+ CTL activity specific for target cells presenting the Ras4–12(V12) epitope exogenously and endogenously. Moreover, both anti-Ras4–12(V12)-derived and anti-Ras4–12(L12)-derived CTL lines were similar insofar as their TCR usage and amino acid contact residues in the Ras4–12(V12) peptide. These experiments demonstrate that modifications can be introduced in tumor-specific peptide epitopes to enhance both in vitro and in vivo immunogenicity. The design of oncogene-specific peptide epitope variants as immunogens may accelerate the generation of anti-tumor T cell responses for cancer immunotherapy.