bluuebunny/crossref_metadata_2025_split huggingface dataset:
Immunologic Characterization of CD7-Deficient Mice
Authors: Lee David M. , Staats Herman F. , Sundy John S. , Patel Dhavalkumar D. , Sempowski Gregory D. , Scearce Richard M. , Jones Dawn M. , Haynes Barton F. 
Published: January 2023

AbstractHuman CD7 is an Ig superfamily molecule that is expressed on mature T and NK lymphocytes. Although in vitro studies have suggested a role for CD7 in lymphoid development and function, the exact function of CD7 in vivo has remained elusive. One patient has been reported with SCID syndrome attributed to CD7 deficiency. To study in vivo functions of CD7, we have generated CD7-deficient mice and assessed their lymphoid development and function. CD7-deficient mice were viable, had normal peripheral blood and spleen lymphocyte numbers, and had normal specific Ab responses with Ag-driven Ig isotype switching. Thymocyte numbers were normal in 4-wk-old, 6-mo-old, and 1-yr-old CD7-deficient mice, but in 3-mo-old CD7-deficient mice, total thymocyte numbers were significantly increased by 60% (p &lt; 0.02) compared with normal age-matched +/+ littermates. CD7-deficient splenocytes proliferated normally in response to various mitogens, including PHA, anti-CD3, Con A, and LPS. While NK cell numbers and cytolytic activity to YAC targets were normal, CD7-deficient mice had lower Ag-induced MHC class I-restricted CTL activity against OVA-transfected target cells than did +/+ control mice. Thus, CD7-deficient mice did not have a SCID syndrome, but rather had transient increases in thymocyte numbers at age 3 mo and altered splenocyte Ag-specific CTL effecter cell activity. These data suggest a role for CD7 in regulating intrathymic T cell development and in mediating CTL effecter function.
IL-16 Activates the SAPK Signaling Pathway in CD4+ Macrophages
Authors: Krautwald Stefan 
Published: January 2023

Abstract
IL-16 has been reported as a modulator of T cell activation and was shown to function as chemoattractant factor. The chemotactic activity of IL-16 depends on the expression of CD4 on the surface of target cells, but the intracellular signaling pathways are only now being deciphered. This report describes IL-16 as an additional activator of the stress-activated protein kinase (SAPK) pathway in CD4+ macrophages. Treatment of these cells with recombinant expressed IL-16 leads to the phosphorylation of SEK-1, resulting in activation of the SAPKs p46 and p54. IL-16 stimulation also leads to the phosphorylation of c-Jun and p38 MAPK (mitogen-activated protein kinase), without inducing MAPK-family members ERK-1 and ERK-2. Interestingly, the IL-16-mediated activation of SAPKs and p38 MAPK in macrophages alone induces no detectable apoptotic cell death. These observations suggest specific regulatory functions of IL-16 distinct from the proinflammatory cytokines TNF-α and IL-1β.
HLA-G Isoforms Produced by Placental Cytotrophoblasts and Found in Amniotic Fluid Are Due to Unusual Glycosylation
Authors: McMaster Michael , Zhou Yan , Shorter Simon , Kapasi Kubra , Geraghty Dan , Lim Kee-Hak , Fisher Susan 
Published: January 2023

Abstract
The human placenta expresses HLA-G, a nonclassical (class Ib) MHC molecule that could play a central role in maternal tolerance of the semiallogeneic fetus. In this work, we report the production of a new mAb, 4H84, that specifically reacts with HLA-G in two formats: immunocytochemistry and immunoblotting. Immunolocalization experiments with 4H84 confirmed our previous finding that cytotrophoblasts within the uterine wall are the only cells in tissue sections of placenta that express the HLA-G protein. Additional experiments showed that both amniocytes and cytotrophoblasts in the amnion-chorion express this protein. Since multiple HLA-G transcripts have been described, we used immunoblotting to study the HLA-G isoforms produced by cytotrophoblasts in vitro and by the amnion-chorion in vivo. Cytotrophoblasts, their conditioned medium, and amniotic fluid samples contained heterodisperse immunoreactive bands (Mr 35,000–50,000). N-deglycosylation by peptide-N-glycosidase F digestion resolved these isoforms into two distinct bands. Cell samples contained primarily an Mr 37,000–42,000 protein, most likely encoded by the full-length mRNA. Conditioned medium and amniotic fluid contained a slightly smaller protein, most likely the secreted form lacking the transmembrane and cytoplasmic regions. Removal of polylactosamine chains by endo-β d-galactosidase digestion significantly reduced the electrophoretic mobility of the immunoreactive bands, suggesting that HLA-G, unlike class Ib molecules studied to date, carries N-acetyllactosamine units. These data show that Mr heterogeneity of HLA-G is due to its novel glycosylation, rather than to the translation of alternatively spliced mRNAs. We postulate that the unusual carbohydrate structures this molecule carries could interact with maternal immune cells and/or stabilize the molecule.
Failure to Activate Cytosolic Phospholipase A2 Causes TNF Resistance in Human Leukemic Cells
Authors: Wu Yu-Ling , Jiang Xu-Rong , Newland Adrian C. , Kelsey Stephen M. 
Published: January 2023

Abstract
Activation of cytosolic phospholipase A2 (cPLA2) by TNF has been shown to be an important component of the signaling pathway leading to cell death. The role of cPLA2 in the cytotoxic action of TNF was investigated in a panel of human leukemic cell lines. TNF could activate cPLA2 only in U937 and HL60 TNF-sensitive leukemic cells, but not in KG1a, CEM, and CEM/VLB100 cells that are relatively resistant to TNF. Pretreatment with 4-bromophenacyl bromide, a cPLA2 inhibitor, rendered U937 and HL60 cell lines resistant to the cytotoxic effect of TNF. Immunoblot and reverse-transcriptase PCR demonstrated that cPLA2 expression was detectable at both transcriptional and translational levels in all leukemic cell lines studied, although CEM and CEM/VLB100 cells expressed cPLA2 mRNA and protein at lower levels. The protein synthesis inhibitor, cycloheximide, increased TNF-induced cPLA2 activity and cytotoxicity in both CEM and CEM/VLB100 cell lines. Low levels of cPLA2 activity in the KG1a cell line could be activated by the cPLA2 activator mellitin, or the calcium ionophore A23187. The data suggest that cPLA2 activity is involved in TNF-induced cytotoxicity in leukemic cells. Resistance to TNF-induced cytotoxicity may involve either protein inhibitors that act upstream of cPLA2 in the TNF-signaling pathway or constitutive defects of cPLA2 itself, possibly involving calcium utilization.
Mechanisms of Macrophage Stimulation Through CD8: Macrophage CD8α and CD8β Induce Nitric Oxide Production and Associated Killing of the ParasiteLeishmania major
Authors: Hirji Nadir , Lin Tong-Jun , Bissonnette Elyse , Belosevic Miodrag , Befus A. Dean 
Published: January 2023

AbstractPrior studies demonstrated that rat macrophages express CD8, which differs from T lymphocyte CD8 within the ligand binding domain. We investigated whether stimulation of macrophage CD8 could induce mediator release and regulate host defense. Cross-linking either CD8α (OX8, 5 μg/ml) or CD8β (341, 10 μg/ml) stimulated nitric oxide (NO) production, which correlated with an up-regulation of inducible NO synthase protein. Cell signaling inhibitors were used to elucidate the pathways of CD8α and CD8β stimulation. Genistein (broad spectrum protein tyrosine kinase inhibitor, 10 μg/ml), PP1 (src family kinase inhibitor, 5 μg/ml), polymyxin B (protein kinase C (PKC) inhibitor, 100 μg/ml), and Ro 31-8220 (PKC inhibitor, 1 μM) significantly inhibited anti-CD8α- and anti-CD8β-stimulated NO production and inducible NO synthase up-regulation, suggesting that tyrosine kinase(s) (src family) and PKC are involved in CD8 signaling. In addition, cross-linking CD8α stimulated NO-dependent macrophage killing of the parasite Leishmania major. For the first time, this work demonstrates that the β-chain of macrophage CD8, in addition to the α-chain, can regulate mediator release. These results further illustrate the importance of this molecule and support our previous data demonstrating differences between macrophage and T lymphocyte CD8. Additional studies on the signaling mechanisms and possible ligand(s) for macrophage CD8 will lead to a greater understanding of inflammation and host defense.
The Role of T Cells in Allografted Tumor Rejection: IFN-γ Released from T Cells Is Essential for Induction of Effector Macrophages in the Rejection Site
Authors: Yoneda Yukio , Yoshida Ryotaro 
Published: January 2023

AbstractAllografted Meth A tumor rejection is T cell dependent, but T cells are inactive toward the allograft; rather, the main effector cells are allograft-induced macrophages (AIM) with MHC haplotype specificity. Here, we examined the role of T cells in the induction of AIM in the rejection site. On day 4.5 after i.p. transplantation of Meth A fibrosarcoma cells to C57BL/6 (B6) mice, we obtained a kind of precursor of AIM (pro-AIM) from the transplantation site by an enrichment technique involving adherence to serum-coated dishes. The noncytotoxic pro-AIM-rich population put into a diffusion chamber became cytotoxic against Meth A cells after 2 days in the peritoneal cavity of an untreated B6 mouse. Similar activation of the chambered B6 pro-AIM-rich population occurred in IFN-γ −/− B6 mice, whereas there was no activation when chambers containing an IFN-γ −/− mouse-derived pro-AIM-rich population were placed in normal or IFN-γ −/− mice, suggesting that IFN-γ is involved in the activation. RT-PCR experiments demonstrated that among bulk infiltrates T cells were the major producer of IFN-γ; and most of the cells in a T cell-eliminated pro-AIM population in a diffusion chamber kept for 2 days in a B6 mouse did not become AIM. Furthermore, IFN-γ −/− B6 mice could not reject allografted Meth A tumor cells, whereas the grafts were rejected by i.p. injections of IFN-γ into the mutant mice. These results indicate that IFN-γ released from allograft-induced T cells is essential for both the activation of a kind of pro-AIM to AIM in the transplantation site and the rejection of an allografted tumor.
IL-6 Produced by Kupffer Cells Induces STAT Protein Activation in Hepatocytes Early During the Course of Systemic Listerial Infections
Authors: Gregory Stephen H. , Wing Edward J. , Danowski Kristine L. , van Rooijen Nico , Dyer Kevin F. , Tweardy David J. 
Published: January 2023

AbstractKupffer cells were the principal source of IL-6 produced in the livers of mice following i.v. inoculation of Listeria monocytogenes. IL-6 mRNA expression and the production of IL-6 were reduced drastically within the nonparenchymal liver cell population derived from mice rendered Kupffer cell depleted by pretreatment with liposome-encapsulated dichloromethylene diphosphonate. A sharp increase in the appearance of activated STAT3 occurred in extracts of purified hepatocytes derived from normal mice infected i.v. with Listeria. Remarkably, the kinetics of this increase overlapped IL-6 mRNA expression by Kupffer cells; each peaked at approximately 30 min postinfection. No increase in STAT3 activation was observed in IL-6-deficient or Kupffer cell-depleted animals. The results of these experiments indicate that the synthesis of IL-6 and the activation of STAT3 within hepatocytes are critical functions of Kupffer cells occurring very early during the course of systemic listerial infections.
Characterization of the Peptide Binding Motif of a Rhesus MHC Class I Molecule (Mamu-A*01) That Binds an Immunodominant CTL Epitope from Simian Immunodeficiency Virus
Authors: Allen Todd M. , Sidney John , del Guercio Marie-France , Glickman Rhona L. , Lensmeyer Gary L. , Wiebe Donald A. , DeMars R. , Pauza C. David , Johnson R. Paul , Sette Alessandro , Watkins David I. 
Published: January 2023

AbstractThe majority of immunogenic CTL epitopes bind to MHC class I molecules with high affinity. However, peptides longer or shorter than the optimal epitope rarely bind with high affinity. Therefore, identification of optimal CTL epitopes from pathogens may ultimately be critical for inducing strong CTL responses and developing epitope-based vaccines. The SIV-infected rhesus macaque is an excellent animal model for HIV infection of humans. Although a number of CTL epitopes have been mapped in SIV-infected rhesus macaques, the optimal epitopes have not been well defined, and their anchor residues are unknown. We have now defined the optimal SIV gag CTL epitope restricted by the rhesus MHC class I molecule Mamu-A*01 and defined a general peptide binding motif for this molecule that is characterized by a dominant position 3 anchor (proline). We used peptide elution and sequencing, peptide binding assays, and bulk and clonal CTL assays to demonstrate that the optimal Mamu-A*01-restricted SIV gag CTL epitope was CTPYDINQM181–189. Mamu-A*01 is unique in that it is found at a high frequency in rhesus macaques, and all SIV-infected Mamu-A*01-positive rhesus macaques studied to date develop an immunodominant gag-specific CTL response restricted by this molecule. Identification of the optimal SIV gag CTL epitope will be critical for a variety of studies designed to induce CD8+ CTL responses specific for SIV in the rhesus macaque.
Altered Intestinal Immune System but Normal Antibacterial Resistance in the Absence of P-Selectin and ICAM-1
Authors: Steinhoff Ulrich , Klemm Uwe , Greiner Manuela , Bordasch Karin , Kaufmann Stefan H. E. 
Published: January 2023

Abstract
ICAM-1 and P-selectin are adhesion molecules that regulate leukocyte migration, extravasation to inflammatory sites, and other immune cell interactions. T cell-mediated resistance against acute infection with Listeria monocytogenes and chronic infection with Mycobacterium bovis Calmette-Guérin bacillus was investigated in mutant mice lacking P-selectin and/or ICAM-1. Mice deficient in P-selectin (Psel−/−), ICAM-1 (ICAM−/−), or the combination of both (Psel−/− × ICAM−/−) showed normal bacterial clearance, comparable delayed-type hypersensitivity reactions, and equivalent memory T cell responses. Additionally, the distribution of αβ vs γδ T lymphocyte populations was examined. Normal lymphocyte distributions were noted in thymus, spleen, and blood, whereas mutant mice showed marked alterations in the intestinal intraepithelial (i-IEL) and lamina propria lymphocytes. Differences in i-IEL populations were reflected functionally by differential lytic activities and cytokine productions of i-IEL populations from mutant mice. Despite these changes within the mucosal immune system of mutant mice, their resistance against oral infection with L. monocytogenes was apparently unimpaired. These findings demonstrate that P-selectin and ICAM-1 are critically involved in the shaping of lymphocyte populations of the gut but have only a minor influence on systemic and regional host defense against intracellular bacteria.
IL-4-Dependent Regulation of TGF-α and TGF-β1 Expression in Human Eosinophils
Authors: Elovic Aram E. , Ohyama Hiroe , Sauty Alan , McBride Jim , Tsuji Takanori , Nagai Masazumi , Weller Peter F. , Wong David T. W. 
Published: January 2023

AbstractTGFs play important roles in wound healing and carcinogenesis. We have previously demonstrated that eosinophils infiltrating into different pathologic processes elaborate TGF-α and TGF-β1. Eosinophils infiltrating hamster cutaneous wounds were found to express TGFs sequentially. In this study, we examined the biologic mediators that may regulate the expression of TGF-α and -β1 by eosinophils. Eosinophils were isolated from the peripheral blood of healthy donors and cultured in the absence or presence of IL-3, IL-4, and IL-5. Cells were analyzed by in situ hybridization and immunohistochemistry. Supernatants from these cultures were assayed for secreted TGF-α and TGF-β1 using TGF-specific ELISAs. IL-3, IL-4, and IL-5 independently up-regulated TGF-β1 mRNA and product expression by eosinophils in all donors. Interestingly, TGF-α production by eosinophils was up-regulated by IL-3 and IL-5 but was down-regulated by IL-4. Consistent with the ability of IL-4 to regulate eosinophil responses, IL-4 signaling molecules are present in human eosinophils. The observation that IL-4 can differentially regulate the expression of TGF-α and TGF-β1 suggests that IL-4 may serve as a physiologic molecular switch of TGF expression by the infiltrating eosinophils in wound healing and carcinogenesis.
Complement Activation Occurs on Subendothelial Extracellular Matrix In Vitro and Is Initiated by Retraction or Removal of Overlying Endothelial Cells
Authors: Hindmarsh Elizabeth J. , Marks Rory M. 
Published: January 2023

AbstractVascular endothelium is continuously exposed to plasma complement, which could generate a potent proinflammatory signal if activated on the vascular wall. Normal endothelium, however, expresses an anti-inflammatory phenotype, which includes resistance to complement fixation. As activated endothelium converts to a proinflammatory phenotype, we investigated the effect of cytokines on endothelial susceptibility to complement fixation. Cytokine-treated HUVEC were exposed to human serum as a source of complement, and C3 deposition was quantified. IL-1β and TNF-α in combination with IFN-γ markedly increased endothelial C3 deposition; however, immunofluorescence microscopy revealed that the endothelial cells had retracted, and that bound C3 was concentrated not on cells but in areas of exposed subendothelial extracellular matrix (ECM). Studies with cell-free ECM indicated that complement activation required only ECM exposure and was independent of cellular activation. C3 deposition on ECM was reproduced by reconstituting the alternative pathway, which generated a stable C3 convertase on ECM, but not on endothelial cells. C3b and iC3b were identified on ECM exposed to purified alternative pathway components and serum, respectively. In conditions associated with endothelial disruption, exposure of subendothelial ECM could induce complement fixation and contribute to inflammation and vascular damage.
Complement Receptor 3 of Macrophages Is Associated with Galectin-1-Like Protein
Authors: Avni Orly , Pur Zivit , Yefenof Eitan , Baniyash Michal 
Published: January 2023

AbstractWe have previously identified a 16-kDa protein with a pI of 5.1 (P16/5.1) that is associated with macrophage CR3. Microsequencing of P16/5.1 indicated exclusive homology to the β-galactoside-binding lectin, galectin-1. Abs specific to a galectin-1 unique peptide reacted with P16/5.1. The association of P16/5.1 with CR3 was specifically inhibited by lactose, which binds with high affinity to galectin-1. These data together with similarities in molecular mass and pI suggest that P16/5.1 is galectin-1. Two-color immunofluorescence staining revealed the expression of galectin-1 on the macrophage surface and its colocalization with CR3. However, a surplus of CR3 was free of galectin-1, and some galectin-1 molecules were associated with cell surface receptors other than CR3. Based on these results we propose two models depicting the functional significance of CR3-galectin-1 association: 1) homodimeric galectin-1 possessing a divalent sugar binding site may act as an extracellular adapter molecule that cross-links CR3 with other receptors; and 2) association of galectin-1 with β-galactosides on the extracellular domain of CR3 may modify the binding affinity of the receptor to its ligand. These possibilities are not mutually exclusive and can clarify the mode by which CR3 transmits signals in macrophages.
Novel Role of Transmembrane SCF for Mast Cell Activation and Eotaxin Production in Mast Cell-Fibroblast Interactions
Authors: Hogaboam Cory , Kunkel Steven L. , Strieter Robert M. , Taub Dennis D. , Lincoln Pam , Standiford Theodore J. , Lukacs Nicholas W. 
Published: January 2023

AbstractMast cell activation can be induced by multiple mechanisms, including IgE-, complement-, and stem cell factor (SCF)-mediated pathways. In addition, the interaction of mast cells with particular cell populations, such as fibroblasts, have also demonstrated increased mast cell reactivity. In these studies, we have investigated the role of fibroblast-mast cell interaction for induction of histamine release and chemokine production and the specific role of SCF during this interaction. Primary pulmonary fibroblast cell lines were grown in culture and used throughout these studies. Mast cells were grown in parallel with fibroblasts by incubation of bone marrow cells with SCF and IL-3. During mast cell-fibroblast coculture, increased histamine release could be attenuated either by separation of the cell populations using a Trans-Well setup, which did not allow cellular contact, or by specific anti-SCF Ab. In addition, a significant increase in eotaxin, a potent eosinophil-specific C-C chemokine, was also observed during fibroblast-mast cell interaction. The production of eotaxin was cell contact dependent and could be inhibited using an anti-SCF Ab or specific antisense therapy. SCF was constitutively produced from fibroblasts in its transmembrane form and could be induced by TNF. SCF-coated plates induced significant mast cell-derived eotaxin production, whereas soluble SCF induced little or no eotaxin, suggesting a necessity for receptor cross-linking for activation. These studies indicate that fibroblast-mast cell contact plays a role in exacerbation of histamine release and eotaxin production.
Low Grade Rhinovirus Infection Induces a Prolonged Release of IL-8 in Pulmonary Epithelium
Authors: Johnston Sebastian L. , Papi Alberto , Bates Philip J. , Mastronarde John G. , Monick Martha M. , Hunninghake Gary W. 
Published: January 2023

Abstract
Rhinoviruses are important respiratory pathogens implicated in asthma exacerbations. The mechanisms by which rhinoviruses trigger inflammatory responses in the lower airway are poorly understood, in particular their ability to infect the lower airway. Bronchial inflammatory cell (lymphocyte and eosinophil) recruitment has been demonstrated. IL-8 is a potent proinflammatory chemokine that is chemotactic for neutrophils, lymphocytes, eosinophils, and monocytes and may be important in the pathogenesis of virus-induced asthma. Increased levels of IL-8 have been found in nasal samples in natural and experimental rhinovirus infections. In these studies we therefore examine the ability of rhinovirus to infect a transformed lower airway epithelial cell line (A549) and to induce IL-8 protein release and mRNA induction. We observed that rhinovirus type 9 is able to undergo full viral replication in A549 cells, and peak viral titers were found 24 h after inoculation. Rhinovirus infection induced a dose- and time-dependent IL-8 release up to 5 days after infection and an increase in IL-8 mRNA expression that was maximal between 3 and 24 h after infection. UV inactivation of the virus completely inhibited replication, but only reduced IL-8 protein production and mRNA induction by half, while prevention of virus-receptor binding completely inhibited virus-induced IL-8 release, suggesting that part of the observed effects was due to viral replication and part was due to virus-receptor binding. These studies demonstrate that rhinoviruses are capable of infecting a pulmonary epithelial cell line and inducing IL-8 release. These findings may be important in understanding the pathogenesis of rhinovirus-induced asthma exacerbations.