bluuebunny/crossref_metadata_2025_split huggingface dataset:
Immunomodulatory effects of transforming growth factor-beta on T lymphocytes. Induction of CD8 expression in the CTLL-2 cell line and in normal thymocytes.
Authors: Inge T H , McCoy K M , Susskind B M , Barrett S K , Zhao G , Bear H D 
Published: December 2022

Abstract
We investigated the role of transforming growth factor-beta 1 (TGF-beta) in regulation of T cell growth and differentiation. Treatment of CTLL-2 cells with TGF-beta inhibited IL-2-dependent proliferation and caused morphologic changes as well as increased adherence. A major change of phenotype in TGF-beta-treated cells was the de novo expression of CD8 alpha chain in 35% of cells, which required the continuous presence of TGF-beta. Of the CD8 alpha+ cells, 20 to 30% co-expressed CD8 beta chain. Increased CD8 expression occurred even in the total absence of cell growth, was not a consequence of growth inhibition, and was not a result of selective growth or survival of CD8+ cells. New RNA synthesis was required for TGF beta-induced CD8 alpha surface expression, inasmuch as this was prevented by treatment with actinomycin D. Northern blot analysis demonstrated that cells treated with IL-2 + TGF-beta rapidly accumulated mRNA encoding both chains of the CD8 dimer, to a level fourfold greater than control by 6 to 12 h. In contrast, the IL-2-dependent increases in IL-2R alpha, IL-2R beta, and Granzyme B mRNA levels in these cultures were profoundly inhibited by TGF-beta. When unfractionated murine thymocytes were stimulated with phorbol dibutyrate plus ionomycin and cultured with IL-2 + TGF-beta, an increase in CD8 alpha mRNA was seen and greater numbers of CD8+ cells with higher levels of CD8 alpha and CD8 beta surface expression resulted, as compared to controls treated with IL-2 alone. Furthermore, similar treatment of CD4-CD8-(double negative) thymocytes with TGF-beta induced de novo CD8 alpha expression by a substantial number of cells, and the majority of these CD8+ cells lacked TCR/CD3. These data suggest that TGF-beta has both positive and negative regulatory effects on the expression of gene products important for T lymphocyte differentiation and function.
B cell activator. Effects on B cell expression of CD23, proliferation, and antibody secretion.
Authors: Marcelletti J F , Matsushita S , Katz D H 
Published: December 2022

Abstract
The studies herein describe a B cell hybridoma-derived, low m.w. (less than 1000 Da), hydrophilic mediator denoted B cell activator (BCA). BCA stimulates B cell expression of IgE-specific FcR (Fc epsilon RII or CD23) in a manner similar to IL-4. However, BCA can be readily distinguished from IL-4 because it does not 1) enhance B cell Ia expression; 2) bind 11B11 anti-IL-4 mAb; or 3) elicit superinduction of Fc epsilon RII expression or IgE production in cultures of LPS-activated B cells. Moreover, BCA is considerably more mitogenic than IL-4 for LPS-activated B cells and, in contrast to IL-4, lacks mitogenicity for anti-mu-activated B cells. BCA can enhance IgG2b and IgG3 production by LPS-activated B cells, responses that are suppressed by IL-4. BCA alone did not stimulate IgE and IgG1 production by LPS-activated B cells, but exerted synergistic activity when combined with IL-4 in stimulating secretion of these antibody isotypes. Finally, secondary Ag-driven IgG1, IgE, and IgA antibody responses can be stimulated by BCA in vitro. Thus, BCA appears to be a novel mediator with broad B cell activation properties.
Heterogeneity of anticardiolipin antibodies defined by the anticardiolipin cofactor.
Authors: Matsuura E , Igarashi Y , Fujimoto M , Ichikawa K , Suzuki T , Sumida T , Yasuda T , Koike T 
Published: December 2022

Abstract
Anticardiolipin antibodies (aCL) found in sera from patients with SLE react with cardiolipin (CL) in the presence of a 50-kDa serum cofactor. The cofactor, which was identified to be beta 2-glycoprotein I by sequencing the N-terminal amino acids, not only enhances CL binding by antibodies in SLE but also depresses it by antibodies associated with syphilis. Cofactor-dependent binding of aCL in SLE to solid phase CL was competitively inhibited by the simultaneous addition of fluid phase CL but was unaffected by either prior or simultaneous addition of a high excess of the cofactor. Binding of aCL in syphilis to solid phase CL was competitively inhibited by either addition of the cofactor or fluid phase CL. aCL in SLE reacted with CL, PS, and PA in the presence of cofactor. In contrast, biotinyl-cofactor bound directly to these anionic phospholipids (PL) and also to PG. These results show that the cofactor-CL complex bears an epitope that confers recognition specificity for aCL in SLE, in contrast with direct CL recognition by syphilitic aCL. The direct binding of the cofactor to PL suggests that the cofactor dependence of aCL binding to PL is due to recognition by aCL of a unique epitope generated upon the formation of the cofactor-CL complex.
Membrane IgM-mediated signaling of human B cells. Effect of increased ligand binding site valency on the affinity and concentration requirements for inducing diverse stages of activation.
Authors: Mongini P K , Blessinger C A , Highet P F , Inman J K 
Published: December 2022

Abstract
The potential for ligand-initiated signal transduction through B cell membrane IgM is assessed in terms of ligand concentration, binding site valency, and binding site affinity for membrane Ig. Estimates of the physicochemical requirements for achieving G0* enhancement of class II MHC expression, G1 entry, and S phase entry in human B cells were made by comparing the stimulatory effects of three affinity-diverse anti-Cmu2 mAb when in bivalent (unconjugated) form, or as mAb-dextran conjugates with low binding site valency (oligovalent ligands) or high binding site valency (multivalent ligands). An increase in binding site number (and concomitant molecular mass) caused a profound reduction in both the minimal concentration and affinity requisites for B cell activation. The enhancing effect of increased binding site valency was most evident for the signaling of those most distal stages in B cell activation, i.e., G1 and S phase, which were difficult to induce with bivalent ligands. The results suggest that highly multimeric TI-2 Ag may be good immunogens because they are able to elicit a full activation response not only from infrequent high affinity B cells, but also from a substantial proportion of the many lower affinity Ag-specific B cells in virgin B cell populations. Interestingly, the activation of B cells by ligands with binding sites of high intrinsic affinity (Ka = 5 x 10(8) M-1) was less influenced by increases in binding site valency than was B cell activation by ligands with intermediate binding site affinity (Ka = 2 x 10(7) M-1). This suggests that the minimal epitope valency requirement for T cell-independent B cell activation by mIg cross-linking Ag may be dependent on the intrinsic affinity with which membrane Ig molecules on a given B cell interact with the redundantly expressed epitopes.
Apoptosis is induced in cells with cytolytic potential by L-leucyl-L-leucine methyl ester.
Authors: Thiele D L , Lipsky P E 
Published: December 2022

Abstract
Previous studies have demonstrated that the selective toxicity of leucyl-leucine methyl ester (Leu-Leu-OMe) for cytotoxic lymphocytes and myeloid cells is dependent on intracellular conversion to membranolytic metabolites by the acyl transferase activity of the granule enzyme dipeptidyl peptidase I (DPPI) that is enriched in these cells. The mechanism of cell death remained unclear, however, and was the subject of the experiments reported here. When human U937, HL60, or THP-1 myeloid tumor cell lines or murine CTLL-2 cells were treated with Leu-Leu-OMe, early release of both cytosolic 51Cr and soluble [3H]TdR labeled DNA fragments was observed, whereas antibody + C treatment of these cells caused only 51Cr release. Killing of U937 or THP-1 cells by incubation with the lysosomotropic amino acid methyl ester, Phe-OMe also induced only 51Cr release without evidence of DNA fragmentation. Preincubation with Zn2+, a known inhibitor of endonuclease activity prevented Leu-Leu-OMe-induced 51Cr or [3H]TdR release from these cell lines, but had no effect on antibody + C or Phe-OMe-induced 51Cr release. Zn2+ also prevented Leu-Leu-OMe-mediated killing of normal human CD16+ NK cells. Zn2+ had no inhibitory effect on Leu-Leu-OMe uptake or intracellular conversion to (Leu-Leu)n-OMe metabolites by these cell lines. Moreover, Zn2+ did not inhibit 51Cr release from nonnucleated E or nucleated U937 targets induced by extracellular production of DPPI-generated metabolites of Leu-Leu-OMe. Thus, killing of cytotoxic lymphocytes and myeloid cells by Leu-Leu-OMe appears to be dependent on generation of metabolites with membranolytic properties, but cell death induced by this process does not involve simple lysis of the plasma membrane. Rather, intracellular production of DPPI generated (Leu-Leu)n-OMe metabolites appears to trigger, an additional Zn(2+)-sensitive process that is associated with induction of apoptosis in cells with cytolytic potential.
Reduced susceptibility to HIV-1 infection of ethyl-methanesulfonate-treated CEM subclones correlates with a blockade in their protein kinase C signaling pathway.
Authors: Hillman K , Qian J , Siegel J N , Roderiquez G , Blackburn R , Manischewitz J , Norcross M , Golding H 
Published: December 2022

Abstract
We have described the isolation of chemically induced CEM subclones that express CD4 receptors and bind soluble gp120, yet show a markedly reduced susceptibility to infection with HIV-1. Two subclones were found to have an abnormal response to the protein kinase C (PKC) activator PMA. PMA treatment induced CD3 and CD25 (IL-2R) receptors on the parental line and on other ethyl-methanesulfonate-derived subclones, but not on these two mutants. Direct assays of PKC activity were conducted. Total cellular PKC enzymatic activity was found to be normal in these subclones. PMA-induced CD4 down-modulation occurred normally. In addition, activation of c-raf kinase was normal. Since HIV-1 long terminal repeat contains two functional nuclear factor kB (NF-kB) regulatory elements, we studied the ability of PMA to induce NF-kB binding activity by different assays. Chloramphenicol acetyl transferase (CAT) assays using the HIV-1 (-139)long terminal repeat-CAT construct showed no PMA induction of CAT activity in these subclones (unlike the parental line and other subclones). Okadaic acid, an inhibitor of phosphatases 1 and 2A, did not overcome the defect in these subclones. Gel retardation assays, using a 32P-probe containing the HIV-1 NF-kB probe and nuclear extracts from PMA-treated cells, showed significantly reduced induction of nuclear NF-kB binding proteins in these two subclones compared with wild type CEM and a control subclone. Deoxycholate treatment of cytoplasmic extracts from these subclones released much reduced NF-kB binding proteins from their cytoplasmic pools. Thus, reduced levels of PKC-induced nuclear NF-kB activity in two T cell subclones did not affect their normal cell growth, but correlated with a pronounced reduction in their susceptibility to HIV-1 infection.
Genomic structure and alternative splicing of 519, a gene expressed late after T cell activation.
Authors: Manning W C , O'Farrell S , Goralski T J , Krensky A M 
Published: December 2022

Abstract
Relatively little is known about the transcriptional control of genes expressed late after T cell activation. We have identified four genes expressed 3 to 5 days after T cell activation by alloantigen or mitogen. Here we report the genomic organization of 519, one of these late T cell activation Ag. Analysis of the genomic clone revealed that 519 consists of six exons. Ribonuclease protection experiments indicated that the most abundant transcript arising from this region is an alternatively spliced form of 519, referred to as 520, which lacks exon 2 and is similar in sequence to NKG5, a cDNA identified in NK cells. These experiments also revealed the existence of two other alternatively spliced RNA transcripts, with heterogeneity in exon 2. Primer extension analysis and ribonuclease protection assays demonstrated that there are two prominent start sites for transcription; however, there is no evidence for the NKG5 transcript in T cells, indicating that NKG5 may represent a NK cell-specific form of 520. The 5' flanking region of this gene contains several previously identified sequences involved in transcriptional regulation, as well as some potentially interesting novel conserved motifs.
HLA-J, a second inactivated class I HLA gene related to HLA-G and HLA-A. Implications for the evolution of the HLA-A-related genes.
Authors: Messer G , Zemmour J , Orr H T , Parham P , Weiss E H , Girdlestone J 
Published: December 2022

Abstract
Ragoussis and co-workers (Genomics 4:301) previously described a class I HLA gene (now designated HLA-J) that maps to within 50 kb of HLA-A. The nucleotide sequences of three HLA-J alleles are reported here. Comparison of the nucleotide sequences of HLA-J alleles shows this gene is more related to HLA-G, A, and H than to HLA-B, C, E, and F. All four alleles of HLA-J are pseudogenes because of deleterious mutations that produce translation termination either in exon 2 or exon 4. Apart from these mutations, the predicted proteins have structures similar to those of HLA-A, B, and C molecules. There is, however, little polymorphism at HLA-J and none at functional positions of the Ag-recognition site. The polymorphism is less than found for HLA-H another HLA-A-related pseudogene. HLA-J appears, like HLA-H, to be an inactivated gene that result from duplication of an Ag-presenting locus related to HLA-A. Nucleotide sequence comparisons show that the HLA-A, H, J, and G genes form a well defined group of "HLA-A-related" loci. Evolutionary relationships as assessed by construction of trees suggest the four modern loci: HLA-A, G, H, and J were formed by successive duplications from a common ancestral gene. In this scheme one intermediate locus gave rise to HLA-A and H, the other to HLA-G and J.
Molecular cloning of a murine IL-6 receptor-associated signal transducer, gp130, and its regulated expression in vivo.
Authors: Saito M , Yoshida K , Hibi M , Taga T , Kishimoto T 
Published: December 2022

Abstract
The IL-6R system comprises two functionally different chains: a ligand binding-chain (IL-6R) and a non-ligand-binding but signal-transducing chain (gp130). gp130 associates with the IL-6-IL-6R complex, resulting in the formation of high-affinity IL-6 binding sites, and transduces the signal. A cDNA for murine gp130 has been cloned from the cDNA library of murine macrophages by using a human gp130 cDNA as a probe. The overall homology with human gp130 was 76.8% at the protein level. The extracellular region of murine gp130, as observed in human gp130, comprises 6 U of a fibronectin type III module and part of this region of approximately 200 amino acids has typical features of a cytokine receptor family. Cloned murine gp130 could transduce the growth signal in a murine IL-3-dependent cell line in response to a complex of IL-6 and soluble IL-6R. Two species of murine gp130 mRNA (7 and 10 kb) were expressed in almost all the cell lines. These transcripts were also ubiquitously expressed in murine tissues, embryonic stem cells, and embryos as early as day 6 of gestation. Administration of IL-6 in mouse caused up-regulation of the gp130 mRNA levels in several tissues. Both gp130 and IL-6R mRNA in liver were up-regulated in vivo by IL-6.
Role of CD3 delta in surface expression of the TCR/CD3 complex and in activation for killing analyzed with a CD3 delta-negative cytotoxic T lymphocyte variant.
Authors: Buferne M , Luton F , Letourneur F , Hoeveler A , Couez D , Barad M , Malissen B , Schmitt-Verhulst A M , Boyer C 
Published: December 2022

Abstract
The TCR is composed of two chains (alpha/beta) containing variable regions associated at the cell surface with invariant chains (CD3 gamma-, delta-, epsilon-, and zeta/eta chains). The latter control assembly and surface expression of the TCR/CD3 complex, as well as its cytoplasmic association with signal transduction relays. In differentiated CTL, stimulation through the TCR leads to the transcriptional activation of genes coding secreted cytokines such as gamma-IFN as well as transcription-independent activation of the lytic machinery. It is not known which of the CD3 components is necessary to transduce the required signals. CD3 gamma- and delta-chains have high sequence homology, in particular in their cytoplasmic domain, and it has been proposed that alpha beta gamma epsilon zeta and alpha beta delta, epsilon zeta may be expressed and function in signal transduction independently. Here, we characterize a CTL clone that has selectively lost expression of the CD3 delta mRNA. This results in expression of partial CD3 complexes devoid of TCR alpha beta chains at the surface of the clone, which are not functional for activation of cytolysis or for gamma-IFN production. Transfection of the clone with either the native or a cytoplasmic exon-deleted CD3 delta gene restores full TCR/CD3 surface expression as well as Ag- or CD3-mediated activation for killing and for gamma-IFN production, indicating that the CD3 delta chain is essential for surface expression of the TCR alpha beta, but that the CD3 delta cytoplasmic portion is not required either for complex assembly or for signal transduction involved in the functions studied.
Characterization of IgG FcR-mediated proliferation of human T cells induced by mouse and human anti-CD3 monoclonal antibodies. Identification of a functional polymorphism to human IgG2 anti-CD3.
Authors: Parren P W , Warmerdam P A , Boeije L C , Capel P J , van de Winkel J G , Aarden L A 
Published: December 2022

Abstract
T cell activation induced by mouse anti-CD3 mAb has shown to be dependent on the Ig isotype of these antibodies. A study of isotype dependency of human antibodies, however, seems more relevant to human effector systems, especially in view of the availability of humanized antibodies for clinical applications. We constructed a panel of mouse and mouse/human chimeric anti-CD3 mAb, which differ only in their CH region and hence have identical binding sites and affinity. By using these antibodies, we now studied their ability to induce T cell proliferation in human PBMC and analyzed the classes of IgG FcR involved in these responses. The human (h)IgG1, hIgG3, and hIgG4, as well as mouse (m)IgG2a and mIgG3 anti-CD3 mAb induced an Fc gamma RI (CD64)-dependent T cell proliferation in all donors. Activation with hIgG2 and mIgG1 anti-CD3 mAb was observed to be mediated via the low affinity Fc gamma RII (CD32). It was found that leukocytes in a normal donor population display a functional polymorphism with respect to hIgG2 anti-CD3 responsiveness. This polymorphism was found to be inversely related to the previously defined Fc gamma RII-polymorphism to mIgG1 anti-CD3 mAb. Monocytes expressing the Fc gamma RII mIgG1 low responder (LR) allele support hIgG2 anti-CD3 induced T cell proliferation efficiently, whereas cells homozygous for the Fc gamma RII mIgG1 high responder (HR) allele do not. This observation could be confirmed in T cell activation studies using hFc gamma RIIa-transfected mouse fibroblasts, expressing either the mIgG1 anti-CD3 HR or LR Fc gamma RII-encoding cDNA.
Autoreactivity of low but not of high CD4 variants of an antigen-specific, I-A-restricted mouse T cell clone.
Authors: Saizawa M K , Hug E , Haque S , Portoles P , Suzuki S , Eichmann K 
Published: December 2022

Abstract
Variant lines expressing high and low surface densities of the accessory molecule CD4 have been developed by repeated preparative flow cytometric cell sortings from the murine Th cell clone D10.G4.1 (D10). The high CD4 variant line (D10H) fully maintained the original I-Ak restricted specificity for conalbumin of wild-type D10 cells. In contrast, the low CD4 variant line (D10L) showed a strong autoreactivity to I-Ak carrying stimulator cells alone which was only slightly augmented by addition of conalbumin. Cell surface molecules other than CD4, including TCR, CD3, CD11a, CD2, CD45, CD44, and MHC class I, remained identical on D10H and D10L sublines as on D10 wild-type cells. The possibility that D10L cells had suffered alterations of their TCR-alpha beta was excluded by demonstrating their reactivity with a panel of eight different anti-clonotypic mAb specific for various epitopes of the D10 TCR. By limiting dilution analysis we show that the majority of responding cells of D10L sublines were autoreactive. Although the reactivity for allogeneic I-A also increased as compared with D10H cells, a clear preference for self-I-Ak was maintained so that a true autoreactive phenotype was evident. The results indicate that the surface concentration of CD4 has a decisive influence on self-non-self discrimination of MHC class II-restricted Th cells.
Effect of IL-3 and stem cell factor on the appearance of human basophils and mast cells from CD34+ pluripotent progenitor cells.
Authors: Kirshenbaum A S , Goff J P , Kessler S W , Mican J M , Zsebo K M , Metcalfe D D 
Published: December 2022

Abstract
Hemopoietic stem cell factor (SCF), which is the ligand for the proto-oncogene c-kit receptor (allelic with W locus) and the product of Sl locus of the mouse, has recently been cloned. The human homologue has also been cloned, and recombinant protein (human rSCF) expressed and purified to homogeneity. To determine the effect of human rSCF in the presence or absence of human rIL-3 on human bone marrow-derived mast cells and basophils, human CD34+ pluripotent progenitor cells, highly enriched (greater than 99%) from bone marrow mononuclear cells, were cultured over agarose surfaces (interphase cultures) in the presence of human rIL-3, human rIL-3 and increasing concentrations of human rSCF, or human rSCF alone. Over 3 to 4 wk, human rSCF acted synergistically with human rIL-3 at all concentrations, producing a three- to fivefold increase in total, mast cell, and basophil numbers over human rIL-3 alone when used at 100 ng/ml. The percentage of cell types in the human rIL-3 and human rIL-3 plus human rSCF cultures, however, remained the same, with basophils constituting 18 to 35% of the final cultured cells, and mast cells 3% or less of the final cell number. In the presence of human rSCF alone, the combined total percentage of mast cells and basophils was 0 to 1.0%, the majority of cells being macrophages. Mast cells cultured in human rIL-3 plus human rSCF, but not human rIL-3 alone, were berberine sulfate positive, suggesting the presence of heparin proteoglycans within granules. Electron microscopic examination of cultures supplemented with human rIL-3 and rSCF, but not human rIL-3 alone, revealed that after 3 wk in culture, mast cell granules contained tryptase and exhibited scroll, reticular, and homogeneous patterns as seen previously in CD34+/3T3 fibroblast cocultures. Thus, CD34+ cells cultured in the presence of both human rIL-3 and rSCF give rise to cultures containing increased numbers of basophils and mast cells, with the mast cells by ultrastructural studies showing evidence of maturation although the percentages of basophils and mast cells arising in these cultures remained unchanged.