bluuebunny/crossref_metadata_2025_split huggingface dataset:
A common TCR beta-chain expressed by CD8+ intestinal mucosa T cells in ulcerative colitis.
Authors: Chott A , Probert C S , Gross G G , Blumberg R S , Balk S P 
Published: December 2022

Abstract
The human intestine contains two populations of anatomically distinct T cells, intraepithelial lymphocytes and lamina propria lymphocytes (LPLs), both of which preferentially use the TCR-alpha beta. Recent studies of TCR alpha- and beta-chain usage by intestinal intraepithelial lymphocytes, which are predominantly CD8+ T cells, have demonstrated that these cells are oligoclonal in normal intestine. This report examined the TCR beta-chains expressed by purified CD4+ and CD8+ T cells from normal colonic lamina propria and from the intestinal mucosa of patients with active ulcerative colitis (UC). The selective expansion of CD8+ T cell clones, and to a lesser extent CD4+ T cell clones, was observed among both normal LPLs and mucosal T cells in UC. These expanded LPL clones from normal donors were all distinct, but the mucosal T cells isolated from five of nine patients with UC contained CD8+ T cells expressing related V beta 3-J beta 1.6 TCRs. These observations provide evidence for an Ag-specific mucosal T cell response in UC. Further studies will be required to identify this Ag and address whether the T cell response to it plays a primary role in initiating the disease or is secondary to the inflammatory response.
Dendritic cells produce macrophage inflammatory protein-1 gamma, a new member of the CC chemokine family.
Authors: Mohamadzadeh M , Poltorak A N , Bergstressor P R , Beutler B , Takashima A 
Published: December 2022

Abstract
Langerhans cells (LC) are skin-specific members of the dendritic cell (DC) family. DC are unique among APC for their capacity to activate immunologically naive T cells, but little is known about their chemotactic recruitment of T cells. We now report that LC produce macrophage inflammatory protein-1 gamma (MIP-1 gamma), a newly identified CC chemokine. MIP-1 gamma mRNA was detected in epidermal cells freshly procured from BALB/c mice, and depletion of I-A+ epidermal cells (i.e., LC) abrogated that expression. MIP-1 gamma mRNA was detected in the XS52 LC-like DC line as well as by 4F7+ splenic DC and granulocyte-macrophage CSF-propagated bone marrow DC. XS52 DC culture supernatants contained 9 and 10.5 kDa immunoreactivities with anti-MIP-1 gamma Abs. We observed in Boyden chamber assays that 1) XS52 DC supernatant (added to the lower chambers) induced significant migration by splenic T cells; 2) this migration was blocked by the addition of anti-MIP-1 gamma in the lower chambers or by rMIP-1 gamma in the upper chambers; and 3) comparable migration occurred in both CD4+ and CD8+ T cells and in both activated and nonactivated T cells. We conclude that mouse DC (including LC) have the capacity to elaborate the novel CC chemokine MIP-1 gamma, suggesting the active participation of DC in recruiting T cells before activation.
A role for c-myc in the regulation of thymocyte differentiation and possibly positive selection.
Authors: Broussard-Diehl C , Bauer S R , Scheuermann R H 
Published: December 2022

Abstract
The purpose of thymocyte differentiation is to establish the T cell repertoire and eliminate nonfunctional and autoreactive T cells. In an analysis of potential regulators of this process, we have found that c-myc expression is down-regulated dramatically during early thymocyte differentiation and subsequently up-regulated along with TCR/CD3 in CD4+8+ cells. Transgenic E beta-myc mice that constitutively express c-myc in thymocytes have a larger proportion of thymocytes with high TCR/CD3 and low heat-stable antigen-1 expression than controls, and an increase in the number of transitional cells with a CD4+CD8low phenotype. Mature E beta-myc T cells respond less vigorously than controls to activation through their TCR/CD3 complex, as measured by proliferation and induction of the activation marker CD69. These results are consistent with a hypothesis in which activation of immature T cells through TCR/CD3 induces c-myc up-regulation and drives thymocytes through the initial stage of positive selection.
Expression and characterization of functionally active recombinant perforin produced in insect cells.
Authors: Liu C C , Persechini P M , Young J D 
Published: December 2022

Abstract
A key cytolytic mediator used by killer lymphocytes, perforin (also known as pore-forming protein or cytolysin), has been shown to be capable of undergoing polymerization to form pores in cell membranes and cause osmotic lysis of target cells. Although perforin has been purified from killer lymphocytes and the coding gene has been cloned and sequenced, information concerning the domain structure of the perforin molecule has remained scarce. To overcome the difficulty in obtaining sufficient amounts of perforin and to further assess the functional relevance of the N-terminal portion of the perforin molecule in its lytic activity, we have attempted in the present study to produce recombinant perforins. Three forms of recombinant mouse perforin, a full-length form and two N-terminal truncated forms, have been expressed in insect (Spodoptera frugiperda (Sf9)) cells using recombinant baculovirus. Biochemical and functional characterization showed the purified full-length recombinant perforin to be capable of lysing target cells, inducing Ca2+ influx into target cells, and forming structural pores in target membranes. Significant lytic activities were also detected for the two truncated recombinant perforins lacking, respectively, the N-terminal 21 amino acid residues and 121 amino acid residues. Time course study showed that the latter acted less efficiently than the former. These results suggest the N-terminal portion of the perforin molecule to be an important, but not the only, domain responsible for the lytic function of the perforin molecule.
A new biologic role for C3a and C3a desArg: regulation of TNF-alpha and IL-1 beta synthesis.
Authors: Takabayashi T , Vannier E , Clark B D , Margolis N H , Dinarello C A , Burke J F , Gelfand J A 
Published: December 2022

Abstract
The complement activation products C3a and C3a desArg are generated in the course of trauma, infection, tissue injury, and ischemia. We have investigated the effects of C3a and C3a desArg on gene expression and protein synthesis of TNF-alpha and IL-1 beta in PBMC. Neither C3a nor C3a desArg alone induced detectable protein or mRNA levels for TNF-alpha and IL-1 beta. C3a modulated LPS-induced TNF-alpha and IL-1 beta synthesis. In nonadherent PBMC, C3a suppressed LPS-induced synthesis of TNF-alpha (20-71% decrease by 0.2-10 microgram/ml of C3a, p less than 0.01) and IL-1 beta (19-57% decrease by 0.5-10 microgram/ml of C3a, p less than 0.01), independently of endogenous production of PGE2. C3a also suppressed LPS-induced mRNA levels for TNF-alpha and IL-1 beta. In contrast, in adherent PBMC, C3a at 5 to 20 microgram/ml enhanced LPS-induced TNF-alpha (75-188% increase, p less than 0.001) and IL-1 beta (119-274% increase, p less than 0.001) synthesis. C3a enhanced TNF-alpha and IL-1 beta mRNA levels in LPS-stimulated adherent cells. Furthermore, C3a desArg shared with C3a the ability to modulate LPS-induced mRNA and protein synthesis for TNF-alpha and IL-1 beta. These results suggest that C3a, thought to be proinflammatory, and C3a desArg, thought to be biologically inactive, are modulators of inflammation. Both C3a and C3a desArg may enhance cytokine synthesis by adherent monocytes at local inflammatory sites, while inhibiting the systemic synthesis of proinflammatory cytokines by circulating cells.
Protective antibodies in murine Lyme disease arise independently of CD40 ligand.
Authors: Fikrig E , Barthold S W , Chen M , Grewal I S , Craft J , Flavell R A 
Published: December 2022

Abstract
Borrelia burgdorferi-infected mice develop acute arthritis that undergoes Ab-mediated resolution. To further investigate the role of B. burgdorferi-specific Abs in Lyme borreliosis, CD40 ligand-deficient (CD40L-deficient) mice were infected with B. burgdorferi. The development and regression of arthritis were similar in CD40L-deficient and control mice. Although CD40L-deficient mice have defects in Ig class switching, infected CD40L-deficient mice developed B. burgdorferi-specific IgG2b Abs. Moreover, the transfer of serum from B. burgdorferi-infected CD40L-deficient animals prevented infection in severe combined immunodeficient mice. These data show that B. burgdorferi-infected CD40L-deficient mice are capable of producing Abs that are protective, despite the inability of these mice to mediate T-dependent immune responses.
Differential utilization of Janus kinase-signal transducer activator of transcription signaling pathways in the stimulation of human natural killer cells by IL-2, IL-12, and IFN-alpha.
Authors: Yu C R , Lin J X , Fink D W , Akira S , Bloom E T , Yamauchi A 
Published: December 2022

Abstract
IL-2-, IL-12-, and IFN-alpha-mediated signaling pathways were analyzed in primary NK cells and in the NK3.3 cell line. Gel mobility shift and immunoprecipitation analyses revealed that in addition to activating STAT3 (signal transducer and activator of transcription-3) and STAT5, IL-2 induced tyrosine and serine phosphorylation of STAT1 alpha, which formed IFN-gamma-activated sequence-binding complexes by itself and with STAT3. Although IL-2 and IFN-alpha activated STAT1 alpha and STAT5, IL-2 predominantly activated STAT5, while IFN-alpha predominantly activated STAT1 alpha. IL-2 induced less STAT1 alpha activation and IFN-alpha induced greater STAT5 activation in NK3.3 cells compared with preactivated primary NK cells. In NK3.3 cells, IL-2 induced comparable formation of c-fos promoter sis-inducible element IFN-gamma-activated sequence-binding complexes containing STAT3 alone with complexes containing STAT3 and STAT1 alpha, while in preactivated primary NK cells, it preferentially induced complexes containing STAT3 and STAT1 alpha. Thus, signaling in NK3.3 cells is not always identical with that in primary NK cells. In contrast to IL-2 and IFN-alpha, IL-12 induced strong tyrosine phosphorylation of STAT4 and variable weak phosphorylation of STAT3. However, supershift analyses using the c-fos promoter sis-inducible element probe showed that IL-12 activated STAT4, STAT1 alpha, and STAT3, and induced complexes containing STAT4 only, STAT4 with STAT1 alpha, STAT3 with STAT1 alpha, or STAT1 alpha only in preactivated primary NK cells. STAT1 alpha activation by IL-12 correlated with increased phosphorylation of serine, but not tyrosine. Finally, IL-2 induced tyrosine phosphorylation of JAK1 and JAK3, while IL-12 induced phosphorylation of JAK2 and TYK2 in both preactivated primary NK and NK3.3 cells. Differential phosphorylation and consequent differential activation of both separate and overlapping STAT proteins by IL-2, IL-12, and IFN-alpha may provide a molecular basis for the similarities and differences in the actions of these cytokines on NK cells.
Selective induction of CD73 expression in human lymphocytes by CD38 ligation: a novel pathway linking signal transducers with ecto-enzyme activities.
Authors: Peola S , Borrione P , Matera L , Malavasi F , Pileri A , Massaia M 
Published: December 2022

Abstract
CD73 is a glycosyl phosphatidylinositol (GPI)-anchored purine salvage enzyme (ecto-5'-nucleotidase (ecto-5'-NT), E.C. 3.1.3.5) whose expression on lymphocytes is dependent on their differentiation state and function. CD73 behaves as an agonistic molecule in signaling via the CD3/TCR and CD2 pathways and is associated with CTL generation, IgG production, and activation of resting naive CD8+ T cells. CD73 deficiency has been reported in a variety of patients with impaired T and/or B cell function. Thus, CD73 holds promise as a molecular target for intervention in the immune system, but the mechanisms regulating its expression are largely unknown. The aim of this study was to gain insight into the regulation of CD73 expression in human lymphocytes. CD38, another cell surface differentiation Ag with ecto-enzyme activities (NAD+ glycohydrolase, ADP-ribosyl cyclase, and cyclic ADP-ribose (cADPR) hydrolase), was found to specifically induce CD73 expression in T and B cell lines as well as in normal adult T and NK cells, cord blood T cells, and thymocytes. CD38 cross-linking induced a rapid export to the cell surface of pre-formed CD73 derived from an intracellular pool and not from de novo biosynthesis. This translocation was dependent on protein tyrosine kinase (PTK) activity and lasted approximately eight hours, after which CD73 was removed from the cell surface by enzymatic cleavage. CD73 was not induced by other agents that activate T cells and CD73 was the only GPI-anchored molecule up-regulated by CD38 ligation out of six analyzed. These results document a novel pathway in human lymphocytes leading from CD38 ligation to CD73 expression, which may result in the rapid acquisition of new functions, including increased purine salvage, increased sensitivity to Ag-induced activation, and the generation of adenosine (Ado) for Ado receptor signaling.
Early production of IL-4 and induction of Th2 responses in the lymph node originate from an MHC class I-independent CD4+NK1.1- T cell population.
Authors: von der Weid T , Beebe A M , Roopenian D C , Coffman R L 
Published: December 2022

Abstract
Splenic CD4+NK1.1+ T cells have been shown to secrete large and transient amounts of IL-4 mRNA 90 min after i.v. injection of anti-CD3 Ab, suggesting that this novel subset of T cells may induce Th2 responses in the spleen by quickly providing IL-4 at the onset of an immune response. beta2-microglobulin-deficient (beta2m(o/o)) mice have been shown to contain strongly reduced numbers of NK1.1+ T cells and to be severely impaired in their capacity for rapid induction of IL-4 mRNA in response to anti-CD3, demonstrating that these cells are MHC class I dependent. To address the role of CD4+NK1.1+ T cells in the induction of Th2 responses against Leishmania major, we have dissected the onset and the outcome of the immune response elicited against the parasite in BALB/c-beta2m(o/o) mice and in anti-NK1.1-treated congenic BALB/c mice expressing the NK1.1 marker (BALB/c-NK1.1+). Both BALB/c-beta2m(o/o) and NK1.1-depleted BALB/c-NK1.1+ mice developed a progressive, nonhealing disease that was indistinguishable from wild-type mice. Upon infection, early induction of IL-4 mRNA in the lymph node was not affected in BALB/c-beta2m(o/o) and in NK1.1-depleted BALB/c-NK1.1+ mice, but was abrogated by injection of a CD4-depleting Ab. These data suggest that, in the lymph node, MHC class I-dependent CD4+NK1.1+ T cells do not play a major role in the generation of Th2 responses against L. major. To investigate whether the inability of NK1.1+ T cells to induce IL-4 production in the lymph node was specific to L. major Ag, mice were challenged with low doses of anti-CD3 Ab s.c. in the footpad. In contrast to the spleen, normal levels of IL-4 mRNA were expressed in the lymph nodes of BALB/c-beta2m(o/o) mice. Thus, the MHC class I-dependent CD4+NK1.1+ cell population that gives a rapid IL-4 response in the spleen appears not to contribute significantly to early induced IL-4 responses in the popliteal lymph nodes.
Single-chain MHC class II molecules induce T cell activation and apoptosis.
Authors: Rhode P R , Burkhardt M , Jiao J , Siddiqui A H , Huang G P , Wong H C 
Published: December 2022

Abstract
MHC class II/peptide complexes displayed on the surface of APCs play a pivotal role in initiating specific T cell responses. Evidence is presented here that components of this heterotrimeric complex can be genetically linked into a single polypeptide chain. Soluble single-chain (sc) murine class II IA(d) molecules with and without covalently attached peptides were produced in a recombinant baculovirus-insect cell expression system. Correct conformation of these molecules was verified based on 1) reactivity to Abs directed against conformational epitopes in IA(d) and 2) peptide-specific recognition of the IA(d)/peptide complexes by T cells. Both sc class II molecules loaded the appropriate peptides and sc class II/peptide fusions were effective in stimulating T cell responses, including cytokine release and apoptosis. Mammalian cells were also found to be capable of expressing functional sc class II molecules on their cell surfaces. The findings reported here open up the possibility of producing large amounts of stable sc class II/peptide fusion molecules for structural characterization and immunotherapeutic applications.
1alpha,25-Dihydroxyvitamin D3 modulates CD38 expression on human lymphocytes.
Authors: Stoeckler J D , Stoeckler H A , Kouttab N , Maizel A L 
Published: December 2022

Abstract
B cells from chronically stimulated tonsils displayed high initial mean CD38 levels that declined during in vitro culture, despite ligation of CD40 and/or the Ag receptor in the presence of IL-4. Exposure to 1alpha,25-dihydroxyvitamin D3 (1,25(OH)2D3) restored the initial CD38 expression on these stimulated cells and up-regulated the Ag on stimulated CD38-/low cells. 1,25(OH)2D3 enhanced CD38 expression by four- to sixfold on CD8- and CD8+ peripheral blood T cells following PHA activation. The EC50 values for induction were 2 to 3 nM. Although all-trans-retinoic acid also induced CD38 expression on stimulated B and T cells, it was less effective than 1,25(OH)2D3. B cell CD38 expression was augmented less by 1,25(OH)2D3 than by IFN-alpha and IFN-gamma. However, T cell CD38 expression was induced more strongly by 1,25(OH)2D3 than by IFN-alpha, and was unaffected by IFN-gamma. The CD38 density on activated 1,25(OH)2D3-treated CD38-/low B and peripheral T cells was proportional to cell size, indicating that hormonal induction depended upon entry into the cell cycle. While IFNs induced CD38 rapidly in stimulated T and B lymphocytes, 1,25(OH)2D3 exerted its effects only after initial 1- to 3-day delays, suggesting a requirement for nuclear 1,25(OH)2D3 receptor up-regulation. In HL-60 cells, which constitutively express the nuclear receptors, 1,25(OH)2D3 rapidly induced CD38 Ag and ectoenzyme activity. The CD38 density on freshly isolated unfractionated tonsillar B lymphocytes and on the activated 1,25(OH)2D3-treated cultured cells was nearly identical for cells within the same size range, indicating that in vitro hormonal exposure reconstituted in vivo CD38 expression levels.
IL-4 protects cells from apoptosis via the insulin receptor substrate pathway and a second independent signaling pathway.
Authors: Zamorano J , Wang H Y , Wang L M , Pierce J H , Keegan A D 
Published: December 2022

Abstract
Although it has been known for some time that IL-4 protects cells from death via apoptosis, very little is known about the mechanism by which IL-4 exerts this effect. In this report, we have studied the molecular mechanisms of the IL-4-induced prevention of apoptosis in the 32D and B cell systems. IL-3 withdrawal has been shown to induce G1-arrest in 32D cells and subsequent death by apoptosis. We found that overexpression of IRS-1 protected 32D cells from death induced by IL-3 deprivation. IL-4 was able to protect 32D cells from apoptosis in the presence or absence of IRS-1. However, the protection from apoptosis of cells cultured in IL-4 was greater in the presence of IRS-1 and it reached levels comparable to those of cells cultured in IL-3. The IRS-1-dependent prevention of apoptosis is linked to the activation of PI 3'-kinase since wortmannin and LY294002, two inhibitors of PI 3'-K, partially inhibited the prevention of apoptosis mediated by IL-4 in 32D-IRS-1 cells after IL-3 withdrawal but not in 32D cells lacking IRS-1 expression. In addition, we found that the IRS/PI 3'-K pathway is, at least in part, responsible for the prevention of apoptosis by IL-4 in normal splenic B cell cultures. In spite of the ability of murine IL-4 to partially protect 32D cells lacking IRS-1 from apoptosis, human IL-4 was not able to prevent cell death in 32D-IRS-1 cells transfected with the human IL-4 receptor mutated in the insulin-lL-4 receptor motif (14R-motif) at amino acid 497 (Y497F). This mutation has previously been shown to abrogate the tyrosine phosphorylation of IRS-1 by human IL-4. These results demonstrate that IL-4 protects 32D cells from apoptosis by two different pathways, one of them mediated by IRS-1. In addition, these results suggest that the 14R-motif of the IL-4R is linked to both pathways.
Rho is a negative regulator of human monocyte spreading.
Authors: Aepfelbacher M , Essler M , Huber E , Czech A , Weber P C 
Published: December 2022

Abstract
Monocyte spreading is a sequential series of events including cell flattening, formation of new actin structures and focal adhesions, as well as development of cytoplasmic projections. To investigate the involvement of the GTP-binding protein Rho in spreading, we treated human blood monocytes or PMA-stimulated U937 or THP1 cells with Clostridium botulinum C3-transferase (C3), which ADP-ribosylates and inactivates Rho in intact cells. The C3 treatment caused 1) a four- to fivefold increase in the number of THP1 cells that spread on fibronectin within 24 h of PMA stimulation, 2) a greater area covered by the spread cells, and 3) accelerated and enhanced development of macrophage-like filopodial and pseudopodial projections. Similar results were obtained with PMA-stimulated U937 cells and human blood monocytes. Furthermore, cell staining revealed disorganization of subcortical actin in C3-treated THP1 cells, whereas circular actin formations at the substrate-attached part of the cells and vinculin-containing focal complexes/adhesions were unaffected. Finally, we found a decrease in membrane-associated RhoA in normal spreading THP1 cells, which suggests endogenous inactivation of Rho and might provide an explanation for the acceleration of spreading caused by the C3-transferase. In conclusion, these results indicate that active Rho is an important, negative regulator of human monocyte spreading by maintaining cell tension and cortical actin organization.
alpha1-Antitrypsin inhibits the lethal response to TNF in mice.
Authors: Libert C , Van Molle W , Brouckaert P , Fiers W 
Published: December 2022

Abstract
alpha1-Antitrypsin, an acute-phase reactant in many species, protects significantly against the lethality induced by TNF or endotoxin in mice. The protection is optimal with a single dose of at least 300 microg i.p. or 100 microg i.v. given 2 h before a lethal challenge, either with a low dose of TNF in the presence of galactosamine or a higher dose of murine TNF alone. Under optimal conditions, the drop in body temperature, the release of liver transaminases, and the increase in clotting time are also inhibited. alpha1-Antitrypsin does not protect against a lethal dose of platelet-activating factor. It is suggested that the protection is due to reduced release of platelet-activating factor.