bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enhanced CTL responses mediated by plasmid DNA immunogens encoding costimulatory molecules and cytokines.
Authors: Iwasaki A , Stiernholm B J , Chan A K , Berinstein N L , Barber B H 
Published: December 2022

Abstract
In the course of examining epitope-specific CTL responses to intramuscular plasmid DNA immunization with influenza nucleoprotein (NP)-expressing vectors, a nonimmunogenic mutant NP (NP(o)) was identified. The coding region of NP(o) differed from the wild-type A/PR/8/34 NP sequence (designated NP(v)) by three amino acid alterations in the carboxyl-terminal portion of the molecule remote from the H-2K(d) epitope (147-155) being monitored. Correction of these mutations restored the immunogenicity of the native sequence, indicating that sequence alterations remote from the CTL epitope in question can profoundly influence its immunogenicity. In an effort to identify general, nonstructural means of enhancing the CTL response to weak plasmid DNA immunogens, vectors were constructed expressing NP(o) in tandem with the costimulatory molecules B7-1 or B7-2. Co-linear expression of NP(o) with B7-2, but not B7-1, significantly increased the NP epitope-specific CTL response. In addition, coinjection of these NP(o) plasmids with granulocyte-macrophage CSF- and/or IL-12-expressing vectors also restored near native NP-specific CTL responses. Thus, the coexpression of certain costimulatory molecules and/or cytokines, in concert with a non-self gene delivered as an intramuscular plasmid DNA immunogen, can significantly enhance Ag-specific CTL responses.
Regulation of CD95 (Fas) ligand expression by TCR-mediated signaling events.
Authors: Latinis K M , Carr L L , Peterson E J , Norian L A , Eliason S L , Koretzky G A 
Published: December 2022

Abstract
Stimulation of mature peripheral T cells by TCR engagement results in activation of signals that drive induction of cytokine gene expression and clonal expansion. However, under some conditions, engagement of the TCR leads instead to apoptosis. Recent studies demonstrate that TCR-stimulated apoptosis requires expression of CD95 ligand on activated T cells followed by an interaction between CD95 ligand and the CD95 receptor also expressed on this population. The experiments reported in this study were designed to address the signaling events triggered by TCR engagement that are important for regulating CD95 ligand gene expression. To approach this, we generated a luciferase reporter construct containing elements of the CD95 ligand promoter. Using a previously described mutant of the Jurkat T cell line, we show that proximal signaling events dependent on the presence of the CD45 tyrosine phosphatase are required for TCR-stimulated CD95 ligand expression. Transient transfection studies demonstrate further that TCR-stimulated activation of the Ras signaling pathway is required for optimal activation of CD95 ligand. Next, in an effort to determine critical transcription factors that regulate CD95 ligand expression, we demonstrate a cyclosporin A-sensitive nuclear factor-AT response element in the promoter region of this gene that is critical for optimal CD95 ligand reporter activity in stimulated T cells. Together, these studies begin a dissection of the biochemical events that lead to expression of CD95 ligand, a required step for TCR-induced apoptosis.
Bidirectional regulation of human B cell responses by CD40-CD40 ligand interactions.
Authors: Miyashita T , McIlraith M J , Grammer A C , Miura Y , Attrep J F , Shimaoka Y , Lipsky P E 
Published: December 2022

Abstract
Positive and negative effects of CD40 ligation on human B cell function were suggested by the observation that mAb to CD40 ligand partially blocked the suppressive influences of anti-CD3-stimulated control CD4+ T cells, as well as the B cell stimulatory effects of anti-CD3 activated mitomycin C-treated CD4+ T cells. To examine the negative effects of CD40 ligation in greater detail, B cells were cultured with anti-CD3 activated mitomycin C-treated CD4+ T cells that expressed optimal levels of CD40 ligand; additional recombinant human CD40 ligand significantly suppressed Ig production, but not proliferation. In contrast, when B cells were stimulated with SAC (formalinized Cowan I strain Staphylococcus aureus) and IL-2 in the absence of T cells, small amounts of recombinant CD40 ligand-stimulated Ig production, whereas larger quantities directly suppressed Ig secretion. The suppressive action of CD40 ligation on Ig production was most apparent after initial B cell activation. Moreover, IgD-memory B cells were significantly more sensitive to inhibition by CD40 ligation than IgD+ naive B cells. Engagement of CD40 not only suppressed Ig secretion by IgD- memory B cells, but also expression of CD38. Finally, activated B cells acquired the capacity to down-regulate CD40 ligand expression by stimulated CD4+ T cells more effectively than resting B cells. These results indicate that during T cell-B cell collaboration, engagement of CD40 can influence Ig production both positively and negatively, depending on the density of CD40 ligand as well as the stage of B cell activation and differentiation.
Expression of an inducible type of nitric oxide (NO) synthase in the thymus and involvement of NO in deletion of TCR-stimulated double-positive thymocytes.
Authors: Tai X G , Toyo-oka K , Yamamoto N , Yashiro Y , Mu J , Hamaoka T , Fujiwara H 
Published: December 2022

Abstract
The present study investigates the role of nitric oxide (NO) in the deletion of TCR-stimulated double-positive (DP) thymocytes. Fetal thymi expressed mRNA for an inducible type of NO synthase (iNOS). The levels of iNOS mRNA became maximal around gestation day 18 with a decline after birth. Administration of anti-CD3 mAb to fetal thymus organ culture (FTOC) or young mice resulted in enhanced expression of mRNAs for iNOS as well as IFN-gamma. Immunohistochemical analyses revealed that iNOS was produced in the corticomedullary junction and medulla. The effects of iNOS-induced NO on anti-CD3-unstimulated or anti-CD3-stimulated thymocytes were examined by culturing them in the presence or absence of a NO-generating compound. Stimulation of DP thymocytes with anti-CD3 alone induced the generation of CD4(low)CD8(low) thymocytes. The subsequent exposure of these anti-CD3-stimulated thymocytes to NO promoted down-regulation of CD4 and CD8 expression. The recovery of viable DP cells was considerably reduced compared with stimulation with anti-CD3 or NO alone. Even in a viable DP population, high incidences of DNA strand breaks were detected in the CD4(low)CD8(low) compartment. In contrast to DP cells, the recovery of viable single-positive cells was not decreased but rather slightly enhanced by treatment with anti-CD3 and/or NO. The recovery of anti-CD3-stimulated thymocytes were also reduced when cultured on the thymic stromal monolayer with the capacity to produce NO upon IFN-gamma stimulation. These results indicate that NO, which is generated in association with TCR stimulation in the thymus, functions to induce deletion of DP thymocytes, especially when their TCR is stimulated.
Development of effector CD8+ T cells in contact hypersensitivity occurs independently of CD4+ T cells.
Authors: Xu H , Banerjee A , Dilulio N A , Fairchild R L 
Published: December 2022

Abstract
Contact hypersensitivity (CHS) is a T cell-mediated response to hapten sensitization of the epidermis. Recent results from this laboratory indicated that hapten sensitization induces two populations of hapten-reactive T cells: CD8+ T cells producing IFN-gamma, which mediate the response, and CD4+ T cells producing IL-4 and IL-10, which function to limit the magnitude and the duration of the response. In the current report we first examined the hapten-presenting cell priming each of these T cell populations and then examined the influence of CD4+ T cell priming on the development of the CD8+ effector T cells. Isolation of hapten-presenting Langerhans cells from the lymph nodes of oxazolone-sensitized mice and transfer to naive mice resulted in the induction of both the regulatory CD4+ and the effector CD8+ T populations. Both CD4+ and CD8+ T cells expressing high levels of the activation determinants CD11a and CD44 appeared in the lymph nodes 3 days after hapten sensitization. The CD8+ T cells producing IFN-gamma and mediating CHS responses following transfer to naive mice were restricted to the high CD44-expressing population. In vitro activation of hapten-immune CD8+ T cells resulted in very low amounts (3 U/ml) of IL-2 production, whereas production of IL-2 by immune CD4+ T cells was approximately 70-fold higher (208 U/ml). Despite this discrepancy in IL-2 production and the coincidental priming of CD4+ and CD8+ T cells by hapten-presenting Langerhans cells during hapten sensitization, the numbers of CD8+/high CD44-expressing T cells in the lymph nodes were nearly identical when CD4+ T cells were present or absent during hapten priming. These results indicate that coincidental priming of CD4+ (and CD8+) T cells by LC does not augment CD8+ T cell development in CHS.
Genomic organization, promoter region analysis, and chromosome localization of the mouse bcl-x gene.
Authors: Grillot D A , González-García M , Ekhterae D , Duan L , Inohara N , Ohta S , Seldin M F , Nuñez G 
Published: December 2022

Abstract
The bcl-x gene, a bcl-2 family member, is highly regulated during lymphoid development, and its expression modulates apoptosis in lymphoid and other cell populations. Several forms of bcl-x mRNAs with different biologic functions have been described in rodents and humans. In this study, we have determined the organization and promoter region of the mouse bcl-x gene in an effort to understand the molecular basis for the different bcl-x mRNA species identified in tissues. We show that mouse bcl-x maps to the distal mouse chromosome 2 at approximately 89 cM, and exhibits a three-exon structure with an untranslated first exon and a facultative first intron. The coding region of bcl-xL is generated by the juncture of exons II and III through a splicing reaction, whereas bcl-xS is generated by an alternatively utilized donor splice site located within exon II. Analysis of multiple cDNAs and primer extension experiments revealed major transcription initiation sites in brain and thymus within a GC-rich region, with multiple Sp1-binding motifs located upstream of exon I. Another promoter was mapped to a 57-bp region localized upstream of the translation initiation codon by transfection of reporter constructs into FL5.12 and K562 cell lines. The remarkable similarity between the genomic regions of bcl-2 and bcl-x suggests that these genes have evolved from a common ancestral gene or through gene duplication.
Defects in cell-mediated immunity affect chronic, but not innate, resistance of mice to Mycobacterium avium infection.
Authors: Doherty T M , Sher A 
Published: December 2022

Abstract
To investigate the role of cell-mediated immunity in the control of Mycobacterium avium infection, we studied the effects of targeted gene disruptions in components of the T lymphocyte-dependent, macrophage-mediated response on resistance of mice to this pathogen. Normal mice developed a chronic, asymptomatic infection, with rapid induction of mRNAs for IFN-gamma, IL-12, and TNF-alpha in spleen, liver, and lung. Bacterial loads in gene knockout, scid, and wild-type mice were indistinguishable for the first 4 wk of infection. However, by 8 wk postinfection, scid mice as well as animals with a targeted disruption of the IFN-gamma gene showed enhanced bacterial growth compared with wild-type controls. In contrast, knockout mice lacking the genes for the TNF-alpha p55/p75 receptors or inducible nitric oxide synthase not only developed comparable bacterial loads to wild-type animals, they also failed to display the splenomegaly and profound suppression of mitogen-induced lymphocyte proliferative responses evident in infected wild-type controls. Thus, M. avium is clearly distinct from other intracellular pathogens (e.g., Leishmania monocytogenes, Toxoplasma gondii, and Mycobacterium tuberculosis) whose initial replication in the host is tightly controlled by Th1-dependent effector mechanisms. Instead, the major effect of host cell-mediated immunity is to limit bacterial growth during the chronic phase of infection. Surprisingly, inducible nitric oxide appears to be more important for the immunopathology than for the host resistance induced by this bacterial pathogen.
Novel anti-inflammatory compounds induce shedding of L-selectin and block primary capture of neutrophils under flow conditions.
Authors: Endemann G , Abe Y , Bryant C M , Feng Y , Smith C W , Liu D Y 
Published: December 2022

Abstract
Leumedins are small molecules that inhibit neutrophil movement into inflamed tissues. These compounds have been shown to inhibit the adherence of neutrophils in static adhesion assays mediated by beta2-integrins. We now report that leumedins, like activating agents, induce the loss of L-selectin from the neutrophil surface. The loss of L-selectin is unrelated to the inhibition of static adhesion, since neutrophils that have been pretreated with leumedins to cause shedding of L-selectin, followed by removal of drug, adhere normally in a static adhesion assay, and this adhesion is inhibited upon readdition of leumedin. In an assay of adhesion to endothelial cells under conditions of physiologic wall shear stress, leumedins prevent both primary capture of neutrophils mediated by L-selectin and firm adherence mediated by beta2-integrins.
Chloroquine inhibits processing of tumor necrosis factor in lipopolysaccharide-stimulated RAW 264.7 macrophages.
Authors: Jeong J Y , Jue D M 
Published: December 2022

Abstract
TNF, a potent immunoregulatory cytokine, is associated with inflammatory diseases such as rheumatoid arthritis, multiple sclerosis, and cerebral malaria when produced in excess. Antimalarial agents such as chloroquine and hydroxychloroquine have been used to treat some rheumatic diseases. Chloroquine was reported to inhibit production of TNF, although the underlying mechanism is poorly understood. In RAW 264.7 cells stimulated with LPS, addition of chloroquine at nontoxic concentrations did not inhibit induction of TNF mRNA and NF-kappaB activity. In the same cells, synthesis and steady state level of 26-kDa pro-TNF were also not significantly reduced by addition of chloroquine, while only small amount of 17-kDa mature TNF was detected in the medium. A pulse-chase experiment of pro-TNF produced in chloroquine-treated cells showed significant inhibition of processing of prohormone. Hydroxychloroquine showed similar inhibitory effect, whereas other lysosomal inhibitors such as ammonium chloride and methylamine had no effect on the production of TNF. Our results suggest that chloroquine inhibits production of TNF at the step of processing of membrane-bound pro-TNF to make soluble mature protein in a lysosome-independent manner.
The human complement C9 gene: identification of two mutations causing deficiency and revision of the gene structure.
Authors: Witzel-Schlömp K , Späth P J , Hobart M J , Fernie B A , Rittner C , Kaufmann T , Schneider P M 
Published: December 2022

Abstract
The ninth component of human complement (C9) is the last of the terminal complement components creating the membrane attack complex. C9 is a single-chain serum protein that is encoded by a gene located on chromosome 5p. Deficiency of terminal complement components is generally associated with recurrent neisseria infections. We studied a previously described Swiss family with inherited C9 deficiency. To identify the genetic basis of C9 deficiency, we developed an approach using exon-specific PCR and direct DNA sequencing. As a cause of C9 deficiency, we found two different point mutations, both generating TGA stop codons in the coding sequence. One mutation, a C to A exchange, was detected in exon 2 at cDNA position 166, the other, a C to T exchange, was located in exon 4 (cDNA position 464). In family studies of three first-degree relatives with heterozygous C9 deficiency, we demonstrated that the two mutations are segregating independently. Therefore, these mutations are sufficient to explain the complete deficiency of both the probands studied. DNA sequencing of the exon-intron junctions revealed a number of revisions regarding the boundaries between exons 4, 5, and 6 as well as between exons 10 and 11. No additional introns were detected in exons 6 and 10. Furthermore, DNA marker studies were conducted using known polymorphisms of the C6, C7, and C9 genes, confirming the linkage of the observed C9 mutations with defined haplotypes.
Inhibition of graft-versus-host disease. Use of a T cell-controlled suicide gene.
Authors: Helene M , Lake-Bullock V , Bryson J S , Jennings C D , Kaplan A M 
Published: December 2022

Abstract
Graft-vs-host disease (GVHD) after allogeneic bone marrow transplantation is associated with significant morbidity and mortality. T cell depletion of the marrow graft, which is currently used to prevent GVHD, has been shown to result in increased graft failure and leukemia relapse. To explore the feasibility of controlling GVHD, transgenic mice with the herpes simplex virus thymidine kinase suicide gene linked to the IL-2 promoter were used as a source of T cells to induce GVHD, which would be modulated with ganciclovir. Injection of herpes simplex virus thymidine kinase transgenic B10.A(5R) spleen cells into lethally irradiated DBA/2 mice resulted in severe acute GVHD. Treatment of the recipient mice with ganciclovir significantly inhibited GVHD-mediated weight loss and mortality and reduced the severity of inflammation in the target organs of GVHD.
Dissociation of apoptosis and activation of IL-1beta-converting enzyme/Ced-3 proteases by ALG-2 and the truncated Alzheimer's gene ALG-3.
Authors: Lacanà E , Ganjei J K , Vito P , D'Adamio L 
Published: December 2022

Abstract
Recent attention has been focused on the members of the IL-1beta-converting enzyme (ICE)/Ced-3 family of cysteine protease as the key components of programmed cell death. However, the molecular events that lead to protease activation and link it to the final apoptotic processes remain poorly characterized. We have shown recently that ALG-2 is a Ca2+-binding protein required for apoptosis. ALG-2 depletion protects the mouse T cell hybridoma 3DO from programmed cell death induced by several stimuli, such as synthetic glucocorticoids, TCR, and Fas triggering. In this work, we show that in the ALG-2-depleted clones the ICE/Ced-3 proteases are normally activated upon TCR, Fas, and dexamethasone stimulation, as determined by cleavage of the endogenous substrate poly(ADP-ribose) polymerase and of a fluorogenic substrate. ALG-3, a truncated form of the familial Alzheimer's disease gene PS2, confers resistance to TCR- and Fas-induced apoptosis. Of interest, it also reduces protease activity and inhibits poly(ADP-ribose) polymerase cleavage upon Fas triggering. Our results suggest that, during apoptosis, ALG-2 functions downstream of, and that ALG-3 interferes with the sequential activation of members of the ICE family proteases.
Apoptosis during B lymphopoiesis in mouse bone marrow.
Authors: Lu L , Osmond D G 
Published: December 2022

Abstract
To evaluate the magnitude of cell death and the critical stages at which it occurs during B lymphopoiesis in mouse bone marrow (BM), we have examined the kinetics of apoptosis at defined stages of B cell differentiation. FACS-sorted B220+ BM cells exhibited a low incidence of morphologically apoptotic cells by electron microscopy. In freshly prepared BM suspensions, the incidence of hypodiploid cells detected by multiparameter flow cytometry was greater among large dividing B220+ surface IgM- (sIgM-) precursor B cells and sIgM(low) immature B lymphocytes than among terminal deoxynucleotidyl transferase+ (TdT+) pro-B cells, small nondividing B220+ sIgM- precursors, and surface IgD+ mature B lymphocytes. During short-term culture, apoptotic cells, identified by both DNA content and in situ DNA strand break labeling, increased linearly with time without macrophage ingestion, providing an assay for the rate of entry into apoptosis. B220+ B lineage cells accumulated in apoptosis more rapidly than cells of other lineages. The apoptotic rate was greater among B220+ sIgM- precursor cells than sIgM+ B cells, and was highest among B220+ mu- pro-B cells. Coculture with stromal cells reduced the apoptotic rate of B220+ sIgM- precursors to a greater extent than that of sIgM+ B lymphocytes. The results lead to estimates of the actual number of B lineage cells undergoing apoptosis per unit time in successive differentiation compartments. The findings indicate that, although influenced by local microenvironmental factors, apoptotic cell death occurs most markedly at two developmental stages associated with Ig heavy chain gene rearrangement and Ag receptor expression, respectively.
Thrombopoietin directly and potently stimulates multilineage growth and progenitor cell expansion from primitive (CD34+ CD38-) human bone marrow progenitor cells: distinct and key interactions with the ligands for c-kit and flt3, and inhibitory effects of TGF-beta and TNF-alpha.
Authors: Ramsfjell V , Borge O J , Cui L , Jacobsen S E 
Published: December 2022

Abstract
Thrombopoietin (Tpo) is a primary regulator of megakaryocyte and platelet production. However, studies in c-mpl-deficient mice suggest that Tpo might also play an important role in early hemopoiesis. Here, the direct ability of Tpo to stimulate stroma-independent growth, multilineage differentiation, and progenitor cell expansion from single primitive CD34+ CD38- human bone marrow cells was investigated. Tpo alone stimulated limited clonal growth, but synergized with c-kit ligand (KL), flt3 ligand (FL), or IL-3 to potently enhance clonogenic growth. Whereas KL and FL in combination stimulated the clonal growth of only 3% of CD34+ CD38- cells, 40% of CD34+ CD38- cells were recruited by KL+FL+Tpo, demonstrating that Tpo promotes the growth of a high fraction of CD34+ CD38- progenitor cells. Additional cytokines (IL-3, IL-6, and erythropoietin (Epo)) did not significantly enhance clonal growth above that observed in response to KL+FL+Tpo. In contrast, Tpo enhanced clonogenic growth in response to KL+FL+IL-3+IL-6+Epo by as much as 80%, implicating a key role for this cytokine in early hemopoiesis. Importantly, we also demonstrate that the majority of Tpo-recruited CD34+ CD38- progenitor cells have a multilineage differentiation potential, and that Tpo promotes prolonged expansion of multipotent progenitors. Specifically, whereas progenitor cells were reduced in cultures containing only KL+FL, addition of Tpo resulted in 40-fold expansion of multipotent progenitors following a 14-day incubation. Finally, we identified inhibitors of Tpo-induced progenitor cell growth, in that TGF-beta as well as TNF-alpha almost completely abrogated the growth of CD34+ CD38- progenitor cells in response to Tpo alone as well as KL+FL+Tpo.