bluuebunny/crossref_metadata_2025_split huggingface dataset:
Administration of recombinant human IL-1 by Staphylococcus enterotoxin B prevents tolerance induction in vivo.
Authors: Nakata Y , Matsuda K , Uzawa A , Nomura M , Akashi M , Suzuki G 
Published: December 2022

Abstract
Peripheral tolerance is important to prevent autoimmunity of T cells against tissue-specific autoantigens in peripheral organs. In certain pathologic situations, peripheral tolerance breaks for unknown reasons and autoimmune diseases occur. Anergy is one of the mechanisms of peripheral tolerance that down-modulates IL-2 synthesis and IL-4 responsiveness by helper T cell clones. In this report, we utilized a model system in which V beta 8+ CD4 T cells were anergized by administration of high doses of Staphylococcus enterotoxin B (SEB) in vivo and investigated an effect of recombinant human (rh) IL-1 on the tolerance induction. RhIL-1 was used because of its ability to induce IL-4 responsiveness in T cells. When rhIL-1 was administered within 24 h after SEB inoculation, the cytokine interfered with tolerance induction; V beta 8+CD4 T cells from mice that had been treated with both SEB and IL-1 proliferated in response to SEB and produced IL-2, IL-4, and IFN-gamma upon TCR/CD28 cross-linking. Delayed administration of rhIL-1 by 48 h failed to do this; T cells did not proliferate in response to SEB, but they retained an ability to produce IL-4 upon TCR/CD28 cross-linking. Administration of rhIL-1 induced better proliferation of V beta 8+CD4 T cells in response to SEB in vivo but did not prevent cell death after proliferation. These results suggest a potential role of inflammatory cytokine IL-1 in the course of autoimmunity via interference with tolerance.
IL-4 induces germ-line IgE heavy chain gene transcription in human fetal pre-B cells. Evidence for differential expression of functional IL-4 and IL-13 receptors during B cell ontogeny.
Authors: Punnonen J , Cocks B G , de Vries J E 
Published: December 2022

Abstract
The present study demonstrates that IL-4 induces germ-line IgE heavy chain (epsilon) gene transcription in human fetal splenic mononuclear cells; fetal bone marrow cells; highly purified sorted surface (s) mu+, CD10+, CD19+ immature B cells; and s mu-, cytoplasmic mu+, CD10+, CD19+ pre-B cells derived from human fetal bone marrow. Similar to observations in normal adult B cells, TGF-beta and IFN-gamma inhibited IL-4-induced germ-line epsilon RNA synthesis in fetal pre-B cells, whereas anti-CD40 mAbs and TNF-alpha had enhancing effects, suggesting that the general mechanisms regulating germ-line epsilon transcription in adult B cells and pre-B cells are similar. IL-13 also induced germ-line epsilon RNA synthesis in s mu+, CD10+, CD19+ immature B cells, but the level of transcription induced by IL-13 was significantly less than that induced by IL-4. Anti-CD40 mAbs strongly synergized with both IL-4 and IL-13 in inducing germ-line epsilon RNA synthesis by fetal immature B cells. Interestingly, IL-13 failed to induce germ-line epsilon RNA synthesis in s mu- pre-B cells even in the presence of anti-CD40 mAbs. These distinct effects of IL-4 and IL-13 suggest that functional IL-13R are expressed at a later stage of B cell ontogeny than IL-4R, and that IL-13, in contrast to IL-4, does not regulate pre-B cell differentiation. Given the fact that IL-4 production appears to be enhanced in atopic individuals, the capacity of IL-4 to induce germ-line epsilon transcription in human fetal immature B cells and pre-B cells suggests that commitment of B cell precursors to IgE-producing cells may occur during intrauterine life and may explain the increased IgE production in neonates with a family history of atopy.
Entry of B cell antigen receptor and antigen into class II peptide-loading compartment is independent of receptor cross-linking.
Authors: Song W , Cho H , Cheng P , Pierce S K 
Published: December 2022

Abstract
The processing and presentation of Ag by B lymphocytes are initiated by Ag binding to the B cell Ag receptor (BCR). Using subcellular fractionation, we recently identified a compartment in B cells in which functional, processed Ag-class II complexes are formed following BCR-mediated Ag internalization, referred to as the peptide-loading compartment. These studies, however, did not address the transport of Ag or BCR from the cell surface to the peptide-loading compartment. In this work, we describe the intracellular trafficking of Ag and surface Ig (sIg) in B cells and evaluate the effect of cross-linking sIg on this intracellular movement. We show that sIg constitutively transports Ag from the plasma membrane, through endosomes, to the MHC class II peptide-loading compartment. The cross-linking of the BCR increases the rate of internalization of sIg and bound Ag, but does not alter the trafficking pathway. Thus, the delivery of Ag to the class II peptide-loading compartment by the sIg is independent of BCR cross-linking, but can be influenced by BCR cross-linking.
Cloning and characterization of a mouse IL-12 receptor-beta component.
Authors: Chua A O , Wilkinson V L , Presky D H , Gubler U 
Published: December 2022

Abstract
Using DNA cross-hybridization, we have isolated and characterized cDNA clones encoding a mouse (mo) IL-12R beta component. Two forms of cDNA were found. The first form encodes a receptor protein that has an overall structure very similar to that of the known human (hu) IL-12R beta with 54% amino acid identity, whereas in the second type of mouse cDNA, the equivalent of the transmembrane region has been deleted. This presumed alternative splicing event also gives rise to a frame shift that results in a receptor with an identical extracellular domain but a different C-terminal sequence. Whether this alternative C terminus is capable of signaling is not yet known. Both types of receptors when expressed in COS-7 cells are membrane associated and bind moIL-12 with an affinity of 1 nM, similar to the affinity of huIL-12R beta for huIL-12. The monomeric size of both moIL-12R beta proteins is about 100 kDa. Similar to huIL-12R beta, moIL-12R beta is expressed at the surface of COS-7 and Ba/F3 cells as a dimer/oligomer whose formation is independent of IL-12 binding. When expressed in Ba/F3 cells, moIL-12R beta binds moIL-12 with two affinities of 50 and 470 pM, corresponding to the medium and high affinity IL-12 binding sites previously identified on mouse Con A lymphoblasts. Despite the higher affinity displayed by the moIL-12R beta in Ba/F3 cells, this receptor alone is not sufficient to transduce a signal, suggesting that another subunit is probably required to generate a functional moIL-12R complex.
Purified X2 binding protein (X2BP) cooperatively binds the class II MHC X box region in the presence of purified RFX, the X box factor deficient in the bare lymphocyte syndrome.
Authors: Moreno C S , Emery P , West J E , Durand B , Reith W , Mach B , Boss J M 
Published: December 2022

Abstract
The conserved X2 box sequence of MHC class II promoters is homologous to TRE/CRE elements, and is required for B cell expression and IFN-gamma induction of MHC class II genes. The X2 binding protein (X2BP) was initially identified as a DNA-binding activity that specifically interacts with the conserved X2 box sequence in both the MHC HLA-DRA and HLA-DRB promoters. To begin to demonstrate that X2BP is the X2 box factor responsible for class II expression in B cells, we have purified X2BP to homogeneity from B cell nuclear extracts using DNA-affinity chromatography. X-box DNA-affinity purification indicates that X2BP is most likely composed of two polypeptides of 120 kDa and 46 kDa. The 120-kDa protein was specifically cross-linked to an X-box probe by exposure to UV irradiation. The 46-kDa subunit of X2BP cross-reacted with anti-rat CREB polyclonal Abs but not to anti-human CREB Abs in Western analysis and supershift assays, indicating that it may be a novel member of the ATF/CREB family. Purified X2BP interacted with purified RFX, a factor that binds to the adjacent X1 box and is absent in some cell lines that are mutant for MHC class II transcription. This interaction increases the DNA-binding half-life of RFX from 5 to at least 60 min, suggesting that X2BP functions in class II MHC gene expression by forming a stable complex with RFX.
Influence of coding-end sequence on coding-end processing in V(D)J recombination.
Authors: Nadel B , Feeney A J 
Published: December 2022

Abstract
The large diversity of the Ig and TCR repertoires is accounted for by combinatorial assembly of the germ-line-encoded V, D, and J gene segments, as well as extensive modification at the junctions during the recombination process. Those modifications, termed coding-end processing, consist of removal and addition of an apparently random number of nucleotides. To obtain further insights into the mechanism of the coding-end processing, we constructed a large data base of several Ig and TCR coding ends obtained in vivo, using conditions that avoid potential bias by cellular selection events. We show that the processing patterns are not random, but rather specific for each coding end, suggesting that specific motifs in the coding-end sequence influence the processing. We found a good correlation between the presence of internal stretches of at least three A.T nucleotides, absence of stretches of G.C nucleotides, and high average nucleotide deletion. Based on a detailed analysis of the processing patterns, we propose that nicks of the hairpin intermediate take place preferentially in potential open structures formed by weaker pairings of A.T stretches. Together, these findings indicate that the sequence of the coding end plays an important role in nonrandom aspects of the recombination mechanism. This suggests that coding-end sequences might have been selected throughout evolution to participate in an early control of the development of the primary repertoire.
Multiple proteins physically interact with PU.1. Transcriptional synergy with NF-IL6 beta (C/EBP delta, CRP3).
Authors: Nagulapalli S , Pongubala J M , Atchison M L 
Published: December 2022

Abstract
PU.1 is a transcription factor that belongs to the ets family of DNA binding proteins. In this study, we show by Far Western blot analyses that multiple nuclear proteins are capable of physically interacting with PU.1. Using radiolabeled PU.1 protein as a probe, we screened a B cell cDNA expression library and isolated a number of clones encoding PU.1 interacting proteins. Three of these clones encode DNA binding proteins (NF-IL6 beta, HMG I/Y, and SSRP), one clone encodes a chaperone protein, and another clone encodes a multifunctional phosphatase. We have characterized the physical and functional interactions between PU.1 and NF-IL6 beta, a leucine zipper transcription factor implicated in inflammatory responses. We found that deletion of the carboxyl-terminal 28 amino acids of PU.1 disrupted PU.1-NF-IL6 beta physical interaction. This deletion disrupts the PU.1 Ets domain. Deletion of the NF-IL6 beta leucine zipper domain also greatly diminished the interaction between these two proteins. In transient expression assays, we found that PU.1 and NF-IL6 beta can functionally cooperate to synergistically activate transcription. Electrophoretic mobility shift assays showed that PU.1 and NF-IL6 beta can simultaneously bind to adjacent DNA binding sites, but apparently do not influence the kinetics or affinity of each other's DNA binding. These results suggest that transcriptional synergy is due to each protein independently influencing the basal transcription complex.
Presentation of endogenous peptide/MHC class I complexes is profoundly influenced by specific C-terminal flanking residues.
Authors: Shastri N , Serwold T , Gonzalez F 
Published: December 2022

Abstract
Processing of intracellular proteins yields 8-11 residue peptides that are displayed on the APC surface as peptide/MHC class I complexes. The remarkably precise excision of antigenic peptides from their precursor polypeptides raises the question of whether specific flanking residues influence presentation efficiency. Here we addressed this question by analyzing the generation of OVA/Kb or influenza nucleoprotein/Db complexes in APC expressing precursors with varying N- or C-terminal flanking residues. We find that T cell responses were not significantly affected by varying the N-terminal flanking residue in the precursors. In contrast, presentation of peptide/MHC complexes was inhibited with the addition of a single C-terminal flanking residue. The most dramatic inhibition was observed with isoleucine, leucine, cysteine, and proline as the C-terminal flanking residues. These residue-specific variations in presentation activity could not be accounted for by differences in the stimulatory activity of corresponding synthetic peptides but were proportional to the relative amounts of naturally processed peptides recovered in the cell extracts. These findings suggest differences in the susceptibility of N- vs C-terminal flanking residues to proteolytic cleavage during Ag processing. The strong influence of specific C-terminal flanking residue(s) could be an important factor affecting the choice of peptides presented to T cells on the APC surface.
Host cell-derived complement control proteins CD55 and CD59 are incorporated into the virions of two unrelated enveloped viruses. Human T cell leukemia/lymphoma virus type I (HTLV-I) and human cytomegalovirus (HCMV).
Authors: Spear G T , Lurain N S , Parker C J , Ghassemi M , Payne G H , Saifuddin M 
Published: December 2022

Abstract
The current study was undertaken to determine whether the human T cell leukemia/lymphoma oncovirus type I (HTLV-I) and the herpesvirus human cytomegalovirus (HCM) incorporate host cell-derived C regulatory proteins. Our experiments showed that both CD59 and CD55 were associated with the external membrane of HTLV-I derived from MT2 cells, since virus could be captured by mAbs to these proteins, and antisera to CD55 and CD59 induced C-mediated lysis of HTLV-I virions. Additionally, both CD55 and CD59 were detected by immunoblot analysis of purified HTLV-I. Purified HCMV produced in human foreskin fibroblasts (HFF) also contained both CD55 and CD59, as detected by immunoblot analysis. However, treatment with anti-CD55, but not anti-CD59, reduced the HCMV infectious titer in the presence of C. Additional studies determined whether HTLV-I-associated CD55 and CD59 participated in the resistance of the virus to C-mediated lysis. Treatment of virus with phosphatidylinositol-specific phospholipase C (PI-PLC), which removes glycosylphosphatidylinositol-anchored CD55 and CD59, increased the sensitivity of HTLV-I to C-mediated destruction in the presence of anti-HTLV-I Abs. Reconstitution of PI-PLC-treated virus with purified CD55 and CD59 restored resistance to C. These experiments show that HTLV-I and HCMV acquire C control proteins from host cells. Together with our previous experiments showing that both CD55 and CD59 are present on HIV-1, these studies demonstrate a mechanism by which a variety of enveloped viruses may acquire resistance to C-mediated destruction.
Incorporation of a 35-kilodalton purified protein from Loxosceles intermedia spider venom transforms human erythrocytes into activators of autologous complement alternative pathway.
Authors: Tambourgi D V , Magnoli F C , Von Eickstedt V R , Benedetti Z C , Petricevich V L , da Silva W D 
Published: December 2022

Abstract
Cutaneous inoculation of Loxosceles spp. spider venoms produces local necrosis, occasionally accompanied by systemic intravascular clotting and hemolysis. In this work, we analyzed the role of the C system on the lysis of human erythrocytes (Eh) induced by Loxosceles venoms in vitro. Eh were treated with whole venom of Loxosceles laeta, Loxosceles gaucho, or Loxosceles intermedia, or with purified venom proteins, and incubated with C-sufficient (Cs-NHS) or C9-depleted autologous (C9d-NHS) serum. Hemolysis was determined spectrophotometrically, and deposition of C components or removal of C regulatory proteins was analyzed by FACS. Eh suspensions exposed to venoms or to a purified 35-kDa protein from L. intermedia were lysed after incubation with Cs-NHS, but not with C9d-NHS. Lysis was blocked by heating the serum at 50 degrees C or Ca2+/Mg2+ chelation by EDTA, but not by Ca2+ chelation with EGTA. Deposition of C1, C2, C3, C4, C5, and factor B on the venom-treated Eh occurred during activation of autologous C. Regulatory proteins decay-accelerating factor (DAF) and CD59 were not altered significantly. Conversion of C-resistant Eh into C-susceptible Eh by the L. intermedia venom was accompanied by incorporation of a 35-kDa venom protein onto the cell surface. Thirty-five-kilodalton-related proteins were detected in the two other Loxosceles venoms by ELISA, using rabbit antiserum against the L. intermedia 35-kDa protein. These data suggest that the C system mediates the lysis of human erythrocytes and, by extension, of other cell types able to incorporate the lytic factor of Loxosceles venoms on their cell surfaces.
Tumor-specific and HLA-A2-restricted cytolysis by tumor-associated lymphocytes in human metastatic breast cancer.
Authors: Linehan D C , Goedegebuure P S , Peoples G E , Rogers S O , Eberlein T J 
Published: December 2022

Abstract
A tumor-specific cytotoxic T lymphocyte (CTL) immune response has been well documented in melanoma, renal cell carcinoma, and ovarian cancer. Conflicting evidence exists regarding the existence of tumor-specific CTL populations in breast cancer. Tumor cells and tumor-associated lymphocytes (TAL) were isolated from the pleural effusions of six consecutive patients with metastatic breast cancer. After solid-phase anti-CD3 stimulation, TAL cultures were expanded with weekly autologous tumor stimulation and low-dose IL-2 for 3 wk. T cell populations were characterized using flow cytometric analysis and ranged from 49 to 91% CD8+, &gt; 98% CD3+, and &lt; 3% CD16+. Functionally, tumor-stimulated TAL showed tumor-specific recognition of autologous tumor cells (241 +/- 142 LU20/10(7)) and no detectable lysis of autologous fibroblasts, Daudi or K562. Cytotoxicity of TAL against HLA-A2+ allogeneic targets was significantly higher when compared with HLA-A2- tumor cell lines (127 +/- 76 vs 6 +/- 18 LU, p = 0.0001). This cytotoxicity against autologous and allogeneic tumor cells was blocked by anti-HLA-A2 mAb and cold HLA-A2+ targets in cold-target inhibition assays. TAL from all HLA-A2+ patients recognized GP2, a known, HER2/neu-derived tumor-associated peptide Ag that is HLA-A2 restricted. We have shown that TAL obtained from metastatic effusions of breast cancer patients contain lymphocytes that can recognize and lyse autologous and allogeneic tumor cells in a tumor-specific, HLA-A2-restricted fashion. In addition, tumor-specific TAL derived from breast cancer patients can selectively lyse HLA-A2+ pancreatic and ovarian tumor cell targets, suggesting a common HLA-A2-restricted tumor-associated Ag between these distinct epithelial cancers. Further elucidation of the cell-mediated immune response to breast cancer and the identification of shared TAA could result in the development of broadly applicable vaccine therapies for many cancers.
Treatment with bacterial LPS renders genetically resistant C57BL/6 mice susceptible to Theiler's virus-induced demyelinating disease.
Authors: Pullen L C , Park S H , Miller S D , Dal Canto M C , Kim B S 
Published: December 2022

Abstract
Theiler's murine encephalomyelitis virus (TMEV) induces a demyelinating disease in susceptible strains, which clinically and histopathologically resembles human multiple sclerosis. Since bacterial LPS produced by Gram-negative bacteria is known to potentiate an immune response and trigger resident central nervous system cells to produce various inflammatory cytokines, we examined the ability of LPS to affect resistance to TMEV-induced demyelinating disease (TMEV-IDD). Intraperitoneal injection of LPS, concomitant with intracerebral of genetically resistant C57BL/6 mice with TMEV, resulted in clinical symptoms in approximately 50% of the group. The increase in susceptibility following LPS treatment correlated with the enhanced levels of TMEV-specific delayed-type hypersensitivity and T cell proliferative responses. Similar treatment with LPS, however, did not accelerate the clinical course of susceptible (SJL/J) or intermediately susceptible (C3H) mice. The LPS-treated C57BL/6 mice displayed an increased viral persistence in the central nervous system when compared with nontreated control mice. Intraperitoneal administration of IL-1 beta could mimic the LPS effect in C57BL/6 mice, suggesting that the increase in susceptibility to TMEV-IDD may function via IL-1 produced following LPS stimulation.
Different patterns of TCR transgene expression in single-positive and double-negative T cells. Evidence for separate pathways of T cell maturation.
Authors: Cheng L , Dejbakhsh-Jones S , Liblau R , Zeng D , Strober S 
Published: December 2022

Abstract
Two lines of transgenic mice were established using the TCR alpha (V alpha 4.4-J alpha 24)- and beta (V beta 9-D beta 1.1-J beta 2.1)-chain genes from a cloned CD4-CD8-alpha beta + (double-negative; DN) T cell line from BALB/c mice. The TCR genes were expressed in CD4+CD8- and CD4-CD8+ (single-positive; SP) and double-positive (DP) T cells in the thymus, and in SP T cells in the peripheral lymphoid tissues, and marrow in one transgenic mouse line, and predominantly in DN T cells in the other. Bone marrow precursor cells from only the DN mouse line generated T cells expressing the V beta 9 transgene during tissue culture. V beta 9+ T cells were found in DN but not SP transgenic mice backcrossed to BALB/c nu/nu mice. The results suggest two separate pathways of T cell maturation, one which generates SP T cells in the thymus, and another which generates DN T cells in both the thymus and bone marrow.
Peptide-dependent expression of HLA-B7 on antigen processing-deficient T2 cells.
Authors: Smith K D , Lutz C T 
Published: December 2022

Abstract
Class I MHC Ag presentation and cell surface expression largely depend on peptide transport into the ER/cis-Golgi by TAP, the transporter associated with Ag processing. Despite this dependency, class I MHC molecules are expressed at low levels on the surface of TAP-deficient T2 cells. We studied the peptide dependency of HLA-B7 expression in transfected T2 cells. HLA-B7 expression was affected by mutations at 19 out of 23 peptide-binding groove residues, but not by nine mutations outside of the peptide-binding groove. T2 cell surface HLA-A2, -B7, and -B51 had similar stabilities, and approximately half of these class I molecules had a long t1/2 consistent with tight peptide binding. Using metabolically labeled T2 cells, HLA-A2-bound peptide eluted as five prominent peaks, but HLA-B7-bound peptide was not detected. In contrast, HLA-B7-eluted peptides were detected spectrophotometrically. These data suggest that HLA-A2 and HLA-B7 molecules utilize distinct TAP-independent peptide supply mechanisms to different degrees. Equivalent amounts of HLA-B7 from TAP- and TAP+ cells yielded similar amounts of peptide, which had the characteristic HLA-B7 peptide-binding motif. The dependency of HLA-B7 cell surface expression on peptide-binding groove residues, the stability of cell surface class I molecules, and the ability to detect HLA-B7-bound peptide indicate that the low level expression on T2 cells is largely peptide dependent. TAP-independent peptide Ag presentation may allow immune recognition of intracellular pathogens that interfere with TAP-dependent peptide transport.