bluuebunny/crossref_metadata_2025_split huggingface dataset:
Emergence of CTL Coincides with Clearance of Virus During Primary Simian Immunodeficiency Virus Infection in Rhesus Monkeys
Authors: Kuroda Marcelo J. , Schmitz Jörn E. , Charini William A. , Nickerson Christine E. , Lifton Michelle A. , Lord Carol I. , Forman Meryl A. , Letvin Norman L. 
Published: December 2022

AbstractThe CTL response was characterized during primary SIV/macaque (SIVmac) infection of rhesus monkeys to assess its role in containing early viral replication using both an epitope-specific functional and an MHC class I/peptide tetramer-binding assay. The rapid expansion of a single dominant viral epitope-specific CTL population to 1.3–8.3% of circulating CD8+ peripheral blood and 0.3–1.3% of lymph node CD8+ T cells was observed, peaking at day 13 following infection. A subsequent decrease in number of these cells was then demonstrated. Interestingly, the percent of tetramer-binding CD8+ T cells detected in the lymph nodes of all evaluated animals was smaller than the percent detected in PBL. These epitope-specific CD8+ T cells expressed cell surface molecules associated with memory and activation. Early clearance of SIVmac occurred coincident with the emergence of the CTL response, suggesting that CTL may be important in containing virus replication. A higher percent of annexin V-binding cells was detected in the tetramer+ CD8+ T cells (range, from 33% to 75%) than in the remaining CD8+ T cells (range, from 3.3% to 15%) at the time of maximum CTL expansion in all evaluated animals. This finding indicates that the decrease of CTL occurred as a result of the death of these cells rather than their anatomic redistribution. These studies provide strong evidence for the importance of CTL in containing AIDS virus replication.
Differential Homing Commitments of Antigen-Specific T Cells After Oral or Parenteral Immunization in Humans
Authors: Kantele Anu , Zivny Jan , Häkkinen Miikka , Elson Charles O. , Mestecky Jiri 
Published: December 2022

AbstractAnimal experiments show that lymphocytes activated in the intestine circulate through mesenteric lymph nodes, lymphatics, and blood, returning to the gut. Homing into intestinal lamina propria is mediated by lymphocyte surface homing receptors, mainly the α4β7-integrin. We studied in humans whether intestinal T cells entering the blood upon antigenic activation would exhibit homing commitments to the gut. Volunteers were immunized with keyhole limpet hemocyanin (KLH) first orally and then parenterally or only parenterally, and the expression of α4β7 on T cells specific for KLH or tetanus toxoid was studied. Circulating T cells were depleted of α4β7+ cells by immunomagnetic selection. This depletion removed a significant proportion of the KLH-specific cells (mean decrease in proliferative response of 71%) in the orally immunized volunteers. No difference in the KLH-induced proliferation was found between the total and the α4β7-depleted populations in volunteers parenterally immunized with KLH, regardless of whether a preceding mucosal priming had taken place or not. In both immunization groups, the depletion of α4β7+ cells had no influence on the proliferative response to tetanus toxoid. We conclude that, in contrast to T cells activated by parenteral immunization, gut-derived T cells have preferential homing commitments to the gut. This commitment was no longer observed after a subsequent parenteral Ag administration. Besides showing that the site of Ag encounter determines the expression of homing receptors, the present study is the first to provide evidence for a circulation of newly activated Ag-specific intestinal T cells back to the gut in humans.
Cell-Surface Expression and Alloantigenic Function of a Human Nonclassical Class I Molecule (HLA-E) in Transgenic Mice
Authors: Pacasova Rita , Martinozzi Silvia , Boulouis Henri-Jean , Ulbrecht Matthias , Vieville Jean-Claude , Sigaux François , Weiss Elisabeth H. , Pla Marika 
Published: December 2022

AbstractWe have introduced the gene (E*01033) encoding the heavy chain of the human nonclassical MHC class I Ag, HLA-E, into the mouse genome. Two founder mice carry a 21-kb fragment, the others bear an 8-kb fragment. Each of the founder mice was mated to mice of an already established C57BL/10 transgenic line expressing human β2-microglobulin (β2m). Cell surface HLA-E was detected on lymph node cells by flow cytometry only in the presence of endogenous human β2m. However, HLA-E-reactive mouse CTL (H-2-unrestricted) lysed efficiently the target cells originating from HLA-E transgenic mice without human β2m, showing that the HLA-E protein can be transported to the cell surface in the absence of human β2m, presumably by association with murine β2m. Rejection of skin grafts from HLA-E transgenic mice demonstrates that HLA-E behaves as a transplantation Ag in mice. HLA-E transgenic spleen cells are effective in stimulating an allogeneic CTL response in normal and human classical class I (HLA-B27) transgenic mice. Furthermore, results from split-well analysis indicate that the majority of the primary in vivo-induced CTL recognizes HLA-E as an intact molecule (H-2-unrestricted recognition) and not as an HLA-E-derived peptide presented by a mouse MHC molecule, although a small fraction (ranging from 4 to 21%) of the primary in vivo-induced CTL is able to recognize HLA-E in an H-2-restricted manner. Based on these observations, we conclude that HLA-E exhibits alloantigenic properties that are indistinguishable from classical HLA class I molecules when expressed in transgenic mice.
Induction of Primary Human CD8+ T Lymphocyte Responses In Vitro Using Dendritic Cells
Authors: Zarling Angela L. , Johnson Julia G. , Hoffman Robert W. , Lee David R. 
Published: December 2022

AbstractThe ability of two different human professional APCs, specifically macrophages (Mφ) and dendritic cells (DC), to stimulate primary responses in human CD8+ T lymphocytes was examined using both allogeneic and Ag-pulsed autologous APCs. CTL responses in CD8+ T lymphocytes isolated from HIV-uninfected donors were evaluated against six different HIV epitopes that are restricted by four different HLA alleles using autologous human PBMC-derived Mφ and DCs for primary stimulation. In a side-by-side experiment, immature DCs, but not Mφ, were able to prime a CTL response against the B14-restricted p24gag 298–306 epitope; mature DCs were also able to prime a response against this epitope. In addition, DCs were capable of priming CD8+ CTL responses against the B8-restricted p24gag 259–267 epitope. In contrast, Mφ were unable to prime strong CTL responses against other epitopes. Since the Ag-specific cytotoxic responses required subsequent rounds of restimulation before they could be detected, the ability of the allogeneic Mφ and DCs to directly prime CD8+ T lymphocyte responses without subsequent restimulation was examined. Similar to the aforementioned peptide-specific results, DCs were more efficient than Mφ in priming both allogeneic proliferative and cytotoxic responses in human CD8+ T lymphocytes. Collectively, these results promote an enhanced status for DCs in the primary stimulation of human CD8+ T lymphocytes.
Synergism for Cytokine-Mediated Disease During Concurrent Endotoxin and Viral Challenges: Roles for NK and T Cell IFN-γ Production
Authors: Nguyen Khuong B. , Biron Christine A. 
Published: December 2022

AbstractViral infections in humans or mice can result in increased sensitivity to challenges with bacteria, bacterial products, or cytokine administration. During lymphocytic choriomeningitis virus infections, mice are more sensitive to the lethal effects of bacterial endotoxin LPS, and in the experiments reported here, were observed at up to 10-fold lower doses in infected than in uninfected mice. The mechanisms responsible for heightened susceptibility under these conditions were evaluated. Kinetic studies demonstrated that virus-infected mice had 3- to 50-fold increases over uninfected mice in peak serum TNF, IL-12, and IFN-γ levels after LPS administration. All three cytokines contributed to lethality during dual challenge, because neutralization of any one of the factors protected from death. Production of TNF was not dependent on either NK or T cells. In contrast, these populations were the predominant sources of IFN-γ, as determined by lack of detectable IFN-γ production in NK and T cell-deficient mice and by intracellular cytokine expression in the cell subsets. Concordant with the demonstrations that both cell populations produced IFN-γ and that this factor was critical for lethality, removal of either subset alone was not sufficient to protect mice from death resulting from dual challenges. Increased resistance required absence of both cell subsets. Taken together, the data show that during viral infections, the normally protective immune responses can profoundly modify reactions to secondary heterologous challenges, to result in dysregulated cytokine expression and consequent heightened detrimental effects.
Mice with Th2-Biased Immune Systems Accept Orthotopic Corneal Allografts Placed in “High Risk” Eyes
Authors: Yamada Jun , Yoshida Munenori , Taylor Andrew W. , Streilein J. Wayne 
Published: December 2022

AbstractCD4+ T cells of the Th1 type play a central role in acute rejection of solid tissue grafts, including orthotopic corneal allografts. Th1 cells, which mediate delayed hypersensitivity, are the polar opposites of CD4+ Th2 cells, and the latter cells cross-regulate Th1 cells through the unique pattern of cytokines they secrete. As such, Th2 cells may have a useful role to play in preventing rejection of corneal allografts. To test this possibility, the immune systems of adult mice were biased toward Th2 responses by immunization with keyhole limpet hemocyanin plus IFA. When immunized subsequently with either OVA or allogeneic corneal tissue, these mice acquired Ag-specific primed T cells of the Th2 type. More important, allogeneic corneas grafted into neovascularized eyes of Th2-biased mice experienced significantly enhanced survival. To demonstrate that enhanced survival was promoted by donor-specific Th2 cells, lymphoid cells from keyhole limpet hemocyanin-immune mice bearing healthy corneal allografts suppressed orthotopic corneal allograft rejection when adoptively transferred into naive, syngeneic recipients. We conclude that acceptance of corneal allografts in neovascularized mouse eyes can be significantly enhanced by biasing the recipient immune system toward Th2 responses.
Expression of L-Selectin Ligands by Transformed Endothelial Cells Enhances T Cell-Mediated Rejection
Authors: Biancone Luigi , Stamenkovic Ivan , Cantaluppi Vincenzo , Boccellino Mariarosaria , De Martino Antonella , Bussolino Federico , Camussi Giovanni 
Published: December 2022

Abstract
Recent immunohistochemical studies have suggested that L-selectin ligands may be implicated in the infiltration of tumors and rejected transplants by lymphocytes. In the present study, polyoma-middle T Ag-transformed endothelial cells (H.end), which typically form in vivo immunogenic vascular tumors resembling Kaposi’s sarcoma, were engineered to express L-selectin ligands by stable transfection with a cDNA encoding α(1,3/4)-fucosyltransferase (H.endft). The ability of these cells to form tumors in the s.c. tissues of normal and immunocompromised mice was then compared with that of H.end cells transfected with the hygromycin-resistance vector only (H.endhygro). H.endhygro cells rapidly formed local and metastatic tumors in normal syngeneic mice, leading to death within 2–3 mo postinjection. By contrast, tumors derived from H.endft cells displayed a slower rate of growth, an absence of metastasis, and marked lymphocyte infiltration. Animals bearing these tumors survived for a significantly longer duration than animals injected with H.endhygro cells. Alternatively, H.endft and H.endhygro cells formed tumors with comparable aggressiveness in immunocompromised mice, resulting in animal death within 3 wk of injection. H.endft but not H.endhygro cells supported L-selectin-dependent adhesion and cytolytic T cell activity in vitro. Taken together, our observations indicate that the in situ expression of fucosyltransferase may significantly influence the cellular immune response in endothelioma tumors. These results may be relevant in understanding the development of vascular opportunistic tumors such as Kaposi’s sarcoma.
Thymus and Autoimmunity: Production of CD25+CD4+ Naturally Anergic and Suppressive T Cells as a Key Function of the Thymus in Maintaining Immunologic Self-Tolerance
Authors: Itoh Misako , Takahashi Takeshi , Sakaguchi Noriko , Kuniyasu Yuhshi , Shimizu Jun , Otsuka Fujio , Sakaguchi Shimon 
Published: December 2022

AbstractThis study shows that the normal thymus produces immunoregulatory CD25+4+8− thymocytes capable of controlling self-reactive T cells. Transfer of thymocyte suspensions depleted of CD25+4+8− thymocytes, which constitute ∼5% of steroid-resistant mature CD4+8− thymocytes in normal naive mice, produces various autoimmune diseases in syngeneic athymic nude mice. These CD25+4+8− thymocytes are nonproliferative (anergic) to TCR stimulation in vitro, but potently suppress the proliferation of other CD4+8− or CD4−8+ thymocytes; breakage of their anergic state in vitro by high doses of IL-2 or anti-CD28 Ab simultaneously abrogates their suppressive activity; and transfer of such suppression-abrogated thymocyte suspensions produces autoimmune disease in nude mice. These immunoregulatory CD25+4+8− thymocytes/T cells are functionally distinct from activated CD25+4+ T cells derived from CD25−4+ thymocytes/T cells in that the latter scarcely exhibits suppressive activity in vitro, although both CD25+4+ populations express a similar profile of cell surface markers. Furthermore, the CD25+4+8− thymocytes appear to acquire their anergic and suppressive property through the thymic selection process, since TCR transgenic mice develop similar anergic/suppressive CD25+4+8− thymocytes and CD25+4+ T cells that predominantly express TCRs utilizing endogenous α-chains, but RAG-2-deficient TCR transgenic mice do not. These results taken together indicate that anergic/suppressive CD25+4+8− thymocytes and peripheral T cells in normal naive mice may constitute a common T cell lineage functionally and developmentally distinct from other T cells, and that production of this unique immunoregulatory T cell population can be another key function of the thymus in maintaining immunologic self-tolerance.
Multiple Roles for IL-12 in a Model of Acute Septic Peritonitis
Authors: Steinhauser Matthew L. , Hogaboam Cory M. , Lukacs Nickolas W. , Strieter Robert M. , Kunkel Steven L. 
Published: December 2022

AbstractThe present study addressed the role of IL-12 in a murine model of septic peritonitis, induced by cecal ligation and puncture (CLP). Although CLP surgery induced IL-12 production at 6 and 24 h after surgery, IL-12 immunoneutralization was clearly deleterious in this model: 54% of CLP mice receiving preimmune serum survived, whereas mice administered IL-12 antisera prior to CLP experienced a 25% survival rate. IL-12 immunoneutralization not only led to increased mortality, but also appeared to promote a shift away from IL-12 and IFN-γ, in favor of IL-10. This cytokine shift corresponded to changes in bacterial load, as CLP mice receiving IL-12 antiserum yielded more CFUs from the peritoneal cavity at 24 h after CLP. To address the role of bacterial infection in IL-12 antiserum-induced mortality following CLP, antibiotics were administered for 4 days after surgery. Despite regular antibiotic administration, IL-12 immunoneutralization still reduced survival in CLP mice. Furthermore, histology of the ceca revealed that mice administered IL-12 antisera failed to show typical organization of the damaged cecum wall. Accordingly, Gram staining revealed bacteria within peritoneal fluids from these mice, while peritoneal fluids from CLP mice that received preimmune serum and antibiotics were free of bacteria. Altogether, these data suggested multiple important roles for IL-12 in the evolution of murine septic peritonitis.
Thrombin-Induced p65 Homodimer Binding to Downstream NF-κB Site of the Promoter Mediates Endothelial ICAM-1 Expression and Neutrophil Adhesion
Authors: Rahman Arshad , Anwar Khandaker N. , True Andrea L. , Malik Asrar B. 
Published: December 2022

Abstract
We investigated the mechanisms by which proinflammatory mediator, thrombin, released during intravascular coagulation and tissue injury, induces ICAM-1 (CD54) expression in endothelial cells. Stimulation of HUVEC with thrombin resulted in dose- and time-dependent increases in ICAM-1 mRNA and cell surface expression and in ICAM-1-dependent endothelial adhesivity toward polymorphonuclear leukocytes. Transient transfection of endothelial cells with ICAM-1 promoter luciferase reporter gene (ICAM-1LUC) constructs indicated that deletion of upstream NF-κB site (−533 bases from translation start site) had no effect on thrombin responsiveness, whereas mutation/deletion of downstream NF-κB site (−223 bases from the translation start site) prevented the activation of ICAM-1 promoter, indicating that the downstream NF-κB site is critical for thrombin inducibility. NF-κB-directed luciferase activity increased ∼3-fold when cells transfected with the plasmid pNF-κBLUC containing five copies of consensus NF-κB site linked to a minimal adenovirus E1B promoter-luciferase gene were exposed to thrombin, indicating that activation of NF-κB was essential for thrombin response. Gel supershift assays demonstrated that thrombin induced binding of NF-κBp65 (Rel A) to downstream NF-κB site of the ICAM-1 promoter. Thrombin receptor activation peptide, a 14-amino-acid peptide representing the new NH2 terminus of proteolytically activated receptor-1, mimicked thrombin’s action in inducing ICAM-1 expression. These data indicate that thrombin activates endothelial ICAM-1 expression and polymorphonuclear leukocyte adhesion by NF-κBp65 binding to the downstream NF-κB site of ICAM-1 promoter after proteolytically activated receptor-1 activation.
Membrane-Anchored Forms of Lipopolysaccharide (LPS)-Binding Protein Do Not Mediate Cellular Responses to LPS Independently of CD14
Authors: Tapping Richard I. , Orr Sally L. , Lawson Evangeline M. , Soldau Katrin , Tobias Peter S. 
Published: December 2022

AbstractInflammatory responses of myeloid cells to LPS are mediated through CD14, a glycosylphosphatidylinositol-anchored receptor that binds LPS. Since CD14 does not traverse the plasma membrane and alternatively anchored forms of CD14 still enable LPS-induced cellular activation, the precise role of CD14 in mediating these responses remains unknown. To address this, we created a transmembrane and a glycosylphosphatidylinositol-anchored form of LPS-binding protein (LBP), a component of serum that binds and transfers LPS to other molecules. Stably transfected Chinese hamster ovary (CHO) fibroblast and U373 astrocytoma cell lines expressing membrane-anchored LBP (mLBP), as well as separate CHO and U373 cell lines expressing membrane CD14 (mCD14), were subsequently generated. Under serum-free conditions, CHO and U373 cells expressing mCD14 responded to as little as 0.1 ng/ml of LPS, as measured by NF-κB activation as well as ICAM and IL-6 production. Conversely, the vector control and mLBP-expressing cell lines did not respond under serum-free conditions even in the presence of more than 100 ng/ml of LPS. All the cell lines exhibited responses to less than 1 ng/ml of LPS in the presence of the soluble form of CD14, demonstrating that they are still capable of LPS-induced activation. Taken together, these results demonstrate that mLBP, a protein that brings LPS to the cell surface, does not mediate cellular responses to LPS independently of CD14. These findings suggest that CD14 performs a more specific role in mediating responses to LPS than that of simply bringing LPS to the cell surface.
Detection of Functional Platelet-Activating Factor Receptors on Human Tonsillar B Lymphocytes
Authors: Bastien Yolande , Toledano Baruch J. , Mehio Noha , Cameron Lisa , Lamoukhaid Bouchaib , Renzi Poalo , Hamid Qutayba , Mazer Bruce D. 
Published: December 2022

AbstractAlthough platelet-activating factor (PAF) receptors have been found on B lymphoblastoid cell lines, the action of PAF on freshly isolated human B cells has not been clearly demonstrated. Using a sensitive semiquantitative reverse-transcriptase PCR, we have found PAF receptor mRNA expressed by tonsillar B lymphocytes, but little in T lymphocytes. Examination of Percoll-fractionated tonsillar B cells indicated that the low density (primarily germinal center cells) and medium density fractions had approximately twofold more PAF receptor mRNA relative to the high density fraction. PAF (10−7 M) stimulated increases in intracellular Ca2+ that were consistently higher in the low and medium density B lymphocytes compared with high density cells. The PAF receptor antagonist Web 2170 inhibited this. Addition of PAF, but not lyso- or enantio-PAF, induced four- to sixfold greater synthesis of IgM and IgG in low and medium density cells compared with unstimulated controls, but had little effect on Ig production by high density cells. To investigate how PAF may influence Ig synthesis, PAF-stimulated B cells were examined for production of the Th2-type cytokines IL-4 and IL-13. PAF induced IL-4 and IL-13 mRNA expression in 17% of CD20+ cells, and IL-4 was detected in cell supernatants after 48–72 h of culture. Together, these data strongly suggest that functional PAF receptors are expressed on B cells in tonsils.
Endothelial Expression of VCAM-1 in Experimental Crescentic Nephritis and Effect of Antibodies to Very Late Antigen-4 or VCAM-1 on Glomerular Injury
Authors: Allen Andrew R. , McHale Julie , Smith Jennifer , Cook H. Terence , Karkar Ayman , Haskard Dorian O. , Lobb Roy R. , Pusey Charles D. 
Published: December 2022

AbstractThe migration of leukocytes into glomeruli in crescentic glomerulonephritis is fundamental to pathogenesis, and offers important therapeutic opportunities. We addressed the importance of VCAM-1, and its leukocyte ligand very late antigen-4 (VLA-4), in such leukocyte migration. In a rat model of nephrotoxic nephritis, glomerular expression of VCAM-1, studied by immunohistochemistry, was up-regulated by day 6 of nephritis. To quantify kidney endothelial VCAM-1 expression, a differential radiolabeled mAb technique was used, which demonstrated that protein expression was not up-regulated by day 2 of nephritis, but rose threefold between days 2 and 5, and remained elevated until at least day 28. An in vivo study was then performed, using blocking mAbs to either VCAM-1 or VLA-4, starting mAb treatment on the day prior to disease induction, and continuing until animals were sacrificed at day 7. mAbs to VLA-4 significantly attenuated renal injury (albuminuria, glomerular fibrinoid necrosis, and crescent formation), but mAbs to VCAM-1 had no significant effect. Surprisingly, the number of leukocytes within glomeruli was unaffected by anti-VLA-4 mAb therapy, despite the reduction in renal injury. Paradoxically, classical markers of macrophage activation were increased in the anti-VLA-4- and anti-VCAM-1-treated animals. This study demonstrates that kidney endothelial VCAM-1, in contrast to ICAM-1, is not up-regulated by day 2 of nephrotoxic nephritis, and plays little part in early leukocyte influx into glomeruli. However, VLA-4 is an important mediator of glomerular injury, operating after transendothelial leukocyte migration, and presumably binding to alternate ligands within the kidney.