bluuebunny/crossref_metadata_2025_split huggingface dataset:
Peptide binding to the class Ib molecule, Qa-1b.
Authors: Kurepa Z , Forman J 
Published: December 2022

Abstract
We have analyzed the interaction of a nonameric peptide (Qdm) derived from the leader sequence of a MHC D region molecule with the class Ib molecule, Qa-1b. Using a direct binding assay with radiolabeled peptide on intact cells, we show specific binding of iodinated Qdm peptide to Qa-1b expressing cells. Specificity was confirmed by experiments in which the binding of iodinated peptide was blocked by unlabeled Qdm and not by control peptides. This allowed us to determine the on- and off-rate of peptide binding to Qa-1b, its binding affinity, and number of available peptide-binding sites per cell. Optimal binding occurs at 4 degrees C, and most of the binding to Qa-1b occurs within the first 10 min and peaks after 3 h. The dissociation of the peptide from cells has a t1/2 of approximately 10 h. The Kd is calculated between 0.2 and 1.1 x 10(-10) M, which is in the range or slightly higher than the Kd we measured for pMCMV to Ld (0.9 x 10(-10) M). The relatively high affinity of binding of the Qdm peptide and low dissociation rate could partially explain why a large portion of Qa-1b molecules are occupied with this single peptide species. We also changed each peptide residue to Ala or Gly to determine its effect on binding. Substitution of Leu at position 9 to Ala strongly reduced peptide binding, while changes at positions 2 (Met--&gt;Ala) and 5 (Arg--&gt;Ala) had a lesser effect. Binding to Qa-1b was completely abrogated with simultaneous Ala mutations at positions 2 and 9.
Conserved CTL epitopes within EBV latent membrane protein 2: a potential target for CTL-based tumor therapy.
Authors: Lee S P , Tierney R J , Thomas W A , Brooks J M , Rickinson A B 
Published: December 2022

Abstract
In healthy virus carriers, EBV is subject to strong CTL responses that principally target the EBV nuclear Ag (EBNA) 3A, 3B, 3C subset of virus proteins. In vitro-reactivated CTLs of this kind have proved very effective in treating EBV-positive immunoblastic lymphoma, a malignancy that expresses the full range of virus proteins. However, targeting other EBV-positive tumors will require CTLs that recognize some of the subdominant viral Ags since in nasopharyngeal carcinoma and EBV-positive Hodgkin's disease, EBNA1, latent membrane protein (LMP) 1, and LMP2 are the only virus proteins present. Studying healthy virus carriers (Caucasian and Chinese), we identified five CTL target epitopes in LMP2 restricted through HLA alleles particularly common in the southern Chinese population, which is most at risk for nasopharyngeal carcinoma (HLA-A2, 50%; A11, 50%; A24, 30%; and B40, 32%). Furthermore, we analyzed the effect of HLA subtype polymorphism, especially in the context of A2 for which four subtypes are present at significant frequency in the Chinese population. As to virus polymorphism, LMP2 epitope sequences (in contrast to EBNA 3A, 3B, and 3C epitopes) were shown to be antigenically conserved among EBV isolates from different world populations, including viruses present in nasopharyngeal carcinoma and Hodgkin's disease biopsy samples. Thus, nasopharyngeal carcinoma and Hodgkin's disease are predicted to express LMP2 proteins that contain conserved CTL target epitopes restricted through common HLA alleles; boosting responses to these epitopes could form the basis of a CTL-based therapy for these malignancies.
Regulation of tumor cell motility and migration by CD63 in a human melanoma cell line.
Authors: Radford K J , Thorne R F , Hersey P 
Published: December 2022

Abstract
CD63 belongs to the transmembrane 4 superfamily of membrane proteins and is expressed in several normal tissues as well as in melanoma cells. Previous reports have suggested that CD63 may play an important role in inhibiting melanoma progression, and this was supported by our studies showing that CD63 was associated with suppression of the growth of melanoma in nude mice. Recently, we and others have shown that CD63 may form noncovalent associations with beta1 integrins, which suggests that the function of CD63 may be related to that of integrins. To further explore the role of CD63 in melanoma, we transfected CD63 into a highly motile, CD63-negative melanoma cell line, KM3, which was shown to express alpha(v)beta5 as the predominant integrin with only trace amounts of beta1 integrins. Following transfection, CD63 was shown to associate with beta1 integrins, and beta1 expression appeared to be up-regulated. Cell motility in serum-containing media was markedly suppressed following transfection of CD63. This inhibition was potentiated by mAbs to CD63, and correlated with the level of CD63 expression. The CD63-transfected, but not the untransfected, melanoma cells showed increased adhesion and migration on the beta1 substrates, fibronectin, laminin, and collagen, whereas rates of migration were similar on the beta5 substrate, vitronectin. These results show that CD63 is involved in regulation of the motility of melanoma cells and their adhesion and migration on substrates associated with beta1 integrins. We suggest they provide further insights into the role of CD63 in tumor progression.
IL-12 induces T helper 1-directed antitumor response.
Authors: Tsung K , Meko J B , Peplinski G R , Tsung Y L , Norton J A 
Published: December 2022

Abstract
Although IL-12 possesses the most potent single-cytokine antitumor efficacy, the mechanism by which IL-12 exerts its antitumor activities remains unclear. Using a complete tumor regression model induced by IL-12 treatment, we demonstrate that the antitumor response induced by IL-12 is mediated by a Th1 cell-directed process, with the macrophage as the effector cell and nitric oxide produced by the activated macrophage as the effector molecule. The induction of the Th1 response by IL-12 depends on the existence of a host T cell response to the tumor before IL-12 administration. IL-12 treatment causes the complete regression of 10-day established s.c. tumors (4-8 mm). Associated with the induction of tumor necrosis, activated macrophages expressing high levels of inducible nitric oxide synthase were found surrounding the tumor. The importance of nitric oxide as the effector molecule was further confirmed by the delay and loss of tumor regression in the presence of a nitric oxide synthase inhibitor in vivo. Examination of tumor-associated T cells indicates that IL-12 induces production of the Th1 cytokine IFN-gamma and suppresses production of IL-2, IL-4, and IL-10 at the tumor site, where these are found to be the predominant cytokines produced by tumor-associated T cells before IL-12 treatment. These findings demonstrate that IL-12 plays an essential role in the induction of an effective Th1 type of cell-mediated immune response against established tumors.
Inhibition of 5-lipoxygenase blocks IL-1 beta-induced vascular adhesion molecule-1 gene expression in human endothelial cells.
Authors: Lee S , Felts K A , Parry G C , Armacost L M , Cobb R R 
Published: December 2022

Abstract
Inflammation is characterized by the recruitment of leukocytes and their subsequent migration from the vasculature into the tissue, where they often cause severe damage. Endothelial cells play a major role in this cascade by expressing cell surface adhesion molecules, such as VCAM-1 and ICAM-1, and chemokines, in response to cytokines. Many of these genes are under the control of inflammatory response transcription factors such as nuclear factor (NF)-kappa B. In this study, we examined the effects of 5-lipoxygenase inhibitors (nordihydroguaiaretic acid and AA861) on IL-1 beta-induced VCAM-1 gene expression in HUVECs. We demonstrated that 5-lipoxygenase inhibitors, but not cyclooxygenase inhibitors, block IL-1 beta-induced VCAM-1 cell surface expression and promoter activity. In transiently transfected HUVECs, NF-kappa B-dependent gene expression was inhibited by 5-lipoxygenase inhibitors. These inhibitors did not block IL-1 beta-induced nuclear translocation of NF-kappa B, inhibitor of kappa B-alpha proteolytic degradation, or significantly reduce phosphorylation of p65. These studies indicate that inhibition of 5-lipoxygenase blocks cytokine-induced VCAM-1 gene expression by reducing the functional activity of NF-kappa B/Rel proteins in HUVECs.
Receptor induction regulates the synergistic effects of substance P with IL-1 and platelet-derived growth factor on the proliferation of bone marrow fibroblasts.
Authors: Rameshwar P , Poddar A , Zhu G , Gascón P 
Published: December 2022

Abstract
The neuropeptide substance P (SP) stimulates CFU in bone marrow (BM) cultures. Although the methylcellulose matrix used in these assays does not provide an appropriate substratum to support adherent-dependent cells, we have observed that cultures containing optimal SP (10(-8)-10(-10) M) develop confluent areas of reticular/fibroblastoid-like cells with CFUs predominantly localized within their vicinity. Characterization (cytochemical and immunofluorescence) of the reticular/fibroblastoid-like cells indicated that they were fibroblasts, the major constituent of the BM stroma. Hemopoietic effects by SP are mediated by the stroma that expresses SP receptors. We studied the effects of SP (10(-7)-10(-11) M) with suboptimal platelet-derived growth factor-BB (PDGF-BB; 5 ng/ml) and IL-1alpha (2 ng/ml), two fibrogenic cytokines, and also hemopoietic regulators. SP by itself and in synergy with either cytokine induced fibroblast proliferation. At optimum SP, IL-1alpha induced 1.6 times the proliferation of PDGF-BB (87 +/- 7 vs 55 +/- 5; n = 12; p &lt; 0.05). The effects of SP were blunted by a specific neurokinin-1 antagonist. Scatchard analysis indicated that SP binds to BM fibroblasts with an approximate Kd of 5 nM. SP induced steady state mRNA for IL-1 receptor IL-1RI and PDGF-BB (PDGF-AR, PDGF-BR) receptors by 7.5-, 6.2-, and 10.5-fold, respectively. Their up-regulation may be partly responsible for the synergistic effects of SP and their ligands. Induction (3-fold) of neurokinin-1 mRNA by IL-1alpha compared with no induction by PDGF-BB may explain the preferred synergism between SP and IL-1alpha. This study indicates that induction of SP, IL-1alpha, and PDGF-BB receptors is important to their synergistic effects on BM fibroblast proliferation. These results bring new insights into stroma-mediated hemopoietic regulation.
Induction of aminopeptidase N/CD13 on human lymphocytes after adhesion to fibroblast-like synoviocytes, endothelial cells, epithelial cells, and monocytes/macrophages.
Authors: Riemann D , Kehlen A , Thiele K , Löhn M , Langner J 
Published: December 2022

Abstract
Aminopeptidase N (APN/CD13) is a transmembrane ectoenzyme occurring on a wide variety of cells. In contrast to monocytes and granulocytes, lymphocytes of peripheral blood do not express CD13 Ag. However, tumor-infiltrating T cells in renal cell cancer as well as synovial fluid T cells from patients suffering from various forms of arthritis can be CD13 positive. To learn more about expression of CD13 in these tissues, we cocultured lymphocytes with different adherent cell lines. CD13 expression was induced in T and B lymphocytes upon adhesion to fibroblast-like synoviocytes, HUVEC, renal tubular epithelial cells, and monocytes/macrophages but not always upon interaction with different tumor cell lines. Induction of APN was rapid, occurring as early as 1 h after coincubation. Expression persisted for &gt;3 days and partially resisted inhibition by cycloheximide. Fixation of adherent cells with paraformaldehyde could not prevent induction of CD13 in lymphocytes. Soluble APN from human kidneys or placenta could not induce CD13 expression on lymphocytes. Induction of CD13 Ag on lymphocytes required direct cell-to-cell contact as shown in experiments using dual chambers. Lymphocytes exhibited an induction not only in CD13 protein but also in Ala-pNA-cleaving enzyme activity and in CD13 mRNA. Lymphocytic expression of CD13 represents a potentially increased cellular ability to inactivate inflammatory mediators. Furthermore, CD13 could be involved in adhesion, in lymphocytic migration, or in the Ag processing of peptides bound in the groove of MHC class II molecules.
Fc gamma receptor cross-linking activates p42, p38, and JNK/SAPK mitogen-activated protein kinases in murine macrophages: role for p42MAPK in Fc gamma receptor-stimulated TNF-alpha synthesis.
Authors: Rose D M , Winston B W , Chan E D , Riches D W , Gerwins P , Johnson G L , Henson P M 
Published: December 2022

Abstract
Fc gamma R cross-linking on murine macrophages resulted in the activation of mitogen-activated protein kinase (MAPK) family members p42MAPK, p38, and c-Jun NH2-terminal kinase (JNK)/stress-activated protein kinase (SAPK). The temporal pattern of activation was distinct for each kinase. p42MAPK activation peaked at 5 min after receptor cross-linking, while peak p38 activity occurred 5 to 10 min later. Maximal JNK/SAPK activation occurred 20 min after Fc gamma R cross-linking. The selective MAPK/extracellular signal-regulated kinase-1 (MEK-1) inhibitor PD 098059 inhibited activation of p42MAPK induced by Fc gamma R cross-linking, but not p38 or JNK/SAPK activation. PD 098059 also inhibited the synthesis of TNF-alpha induced by Fc gamma R cross-linking (IC50 approximately 0.1 microM). Together, these results suggest that 1) the activation of MAPKs may play a role in Fc gammaR signal transduction, and 2) the activation of p42MAPK is necessary for Fc gamma R cross-linking-induced TNF-alpha synthesis.
Human IL-1Ra gene transfer into human synovial fibroblasts is chondroprotective.
Authors: Müller-Ladner U , Roberts C R , Franklin B N , Gay R E , Robbins P D , Evans C H , Gay S 
Published: December 2022

Abstract
Rheumatoid arthritis (RA) is characterized by progressive destruction of synovial cartilage. In vitro, degradation of cartilage is stimulated by IL-1, a proinflammatory cytokine, which is released from RA synovial fibroblasts (RA-SF). To determine whether gene therapy using the gene encoding the naturally occurring inhibitor of IL-1, IL-1 receptor antagonist (IL-1Ra) is feasible, IL-1 Ra-transduced RA-SF were coimplanted with normal human cartilage in SCID mice. The IL-1 Ra-transduced RA-SF continued to secrete IL-1Ra over a 60-day period. Cartilage that was coimplanted with RA-SF transduced with a marker gene exhibited progressive, chondrocyte-mediated cartilage degradation, whereas no such degradation was observed in cartilage that was coimplanted with RA-SF transduced with IL-1 Ra. Thus, gene therapy using a retrovirus-based gene delivery system appears to be a feasible approach to effectively modifying the local synovial environment.
Immune deviation in relation to ocular immune privilege.
Authors: Streilein J W , Ksander B R , Taylor A W 
Published: December 2022

Abstract
Immune privilege in the eye is a dynamic state in which the immune response to ocular Ags is molded and modified by the eye itself. Immune privilege correlates with systemic alterations in the immune response such that deviant forms of immunity emerge. The eye itself contributes to immune deviation, in part by displaying unique immunoregulatory factors in aqueous humor and expressed on ocular cells. When T cells encounter Ag in the eye, they can become anergic, undergo apoptosis, secrete TGF-beta, and/or release soluble regulatory factors containing the TCR alpha-chain. Ags taken up by indigenous APC escape the eye and reach the spleen where they activate a unique spectrum of Ag-specific T and B cells. The absence of systemic delayed hypersensitivity and complement-fixing Abs in this deviant response probably relates to the fact that inflammation is deleterious to vision and leads to blindness. Immune privilege is the eye's way of protecting its vital function from the ravages of immunopathogenic injury.
CD45RA-RO+ (memory) but not CD45RA+RO- (naive) T cells roll efficiently on E- and P-selectin and vascular cell adhesion molecule-1 under flow.
Authors: Lichtman A H , Ding H , Henault L , Vachino G , Camphausen R , Cumming D , Luscinskas F W 
Published: December 2022

Abstract
This study examines the molecular mechanisms that underlie the observed preferential interactions of memory vs naive T cells with activated vascular endothelium. Many more CD4+ CD45RO+ (memory) cells adhered to 6-h TNF-alpha-activated human umbilical vein endothelium under flow than CD4+CD45RA+ (naive) cells. Adhesion studies were performed using Chinese hamster ovary (CHO) cell monolayers expressing human E- or P-selectin (CHO-E and CHO-P, respectively) or with soluble vascular cell adhesion molecule-1 (VCAM-1)-coated glass surfaces. Under flow at 1.8 dynes/cm2, RO+ T cells rolled extensively at low velocity on both CHO-P and CHO-E monolayers and VCAM-1, whereas very few RA+ T cells interacted with these surfaces. VCAM-1-dependent rolling was blocked completely by anti-very late Ag-4 (VLA-4) Abs. Purified CD4+RA+ T cells could be converted to RO+ cells by mitogen stimulation and 7-day culture in vitro, and this correlated with the acquisition of the ability to roll on E- or P-selectin, but not on VCAM-1 under flow. In summary, these data indicate that CD45RO+ cells interact with E- and P-selectins and VCAM-1 much more effectively than do CD45RA+ cells under flow conditions, and these adhesion pathways may contribute, either individually or in combination, to the preferential recruitment of memory T cells to peripheral sites of inflammation.
Differential contact of disparate class I/peptide complexes as the basis for epitope cross-recognition by a single T cell receptor.
Authors: Loftus D J , Chen Y , Covell D G , Engelhard V H , Appella E 
Published: December 2022

Abstract
In an effort to better understand functional recognition of structurally dissimilar ligands by a single TCR, a model system for studying cross-recognition of disparate peptide/class I complexes was developed using the murine (H-2b) CTL clone AHIII12.2, which is reactive to a human self-peptide (p1049) bound to an HLA-A2.1 molecule. We identified a second complex comprised of a synthetic peptide, designated p1058, bound to H-2Db that is recognized by clone AHIII12.2. In cytolysis assays, dose-response profiles for peptides p1049 and p1058 pulsed onto the appropriate target cells were comparable, suggesting that p1049/A2.1 and p1058/Db form functionally equivalent epitopes. To probe the interaction between each complex and the TCR of AHIII12.2, singly substituted analogues of each peptide were tested for their activity in lysis assays. Differences were observed between the two epitopes with respect to permissible residue substitutions at each peptide position from P3 to P8; marked differences were evident at P3 and at P8. The results obtained suggest that this TCR forms critical contacts with atoms at peptide positions P3 and P5 of p1049/A2.1 and at P5 and P8 of p1058/Db, and that TCR cross-recognition of these ligands is a function of both shared and complex-specific contacts made with each epitope. These findings further highlight the versatile reactivity that may be shown by a single TCR and suggest a basis for the recognition of peptide ligands sharing only a limited set of structural features.
IL-2-induced IL-5 synthesis, but not proliferation, of human CD4+ T cells is suppressed by FK506.
Authors: Mori A , Suko M , Kaminuma O , Inoue S , Ohmura T , Hoshino A , Asakura Y , Terada E , Miyazawa K , Nosaka C , Okumura Y , Ito K , Okudaira H 
Published: December 2022

Abstract
Regulation of T cell IL-5 synthesis was investigated using human Th cell clones. Immunosuppressant FK506 suppressed IL-5 synthesis of T cells activated through TCR in a dose-dependent manner. IL-5 gene transcription and protein synthesis were also induced in the same T cell clones upon stimulation with IL-2 and were suppressed by FK506 in a dose response similar to that induced by TCR stimulation. In contrast to TCR stimulation, neither activating protein-1, nuclear factor-AT (NF-AT), nor NF-kappaB binding activity was significantly up-regulated by IL-2 stimulation. Human IL-5 promoter/enhancer-luciferase gene construct transfected to T cell clones was transcribed upon either TCR or IL-2 stimulation and was clearly down-regulated by FK506, indicating that the approximately 500-bp human IL-5 gene segment located 5' upstream of the coding region contained FK506-sensitive enhancer elements. Our present findings clearly indicate that FK506-sensitive signaling molecules are involved in T cell IL-5 production induced by both TCR and IL-2 stimulation and suggest that IL-2 receptor signal leading to IL-5 gene transcription is transduced by a unique FK506-sensitive pathway other than the Ca2+-dependent signal transduction pathway, such as the calcineurin-NF-AT system.
Platelet-activating factor abrogates apoptosis induced by cross-linking of the surface IgM receptor in a human B lymphoblastoid cell line.
Authors: Toledano B J , Bastien Y , Noya F , Baruchel S , Mazer B 
Published: December 2022

Abstract
B lymphocyte development is characterized by deletion, via apoptosis, of immature cells that are stimulated via the B cell receptor in the absence of a second signal. We have investigated whether platelet-activating factor (PAF), a potent B lymphocyte activator, can provide a complementary signal with B cell receptor ligation to abrogate apoptosis. Cross-linking of the surface IgM on Ramos B lymphoblastoid cells using anti-IgM Abs (2 microg/ml) caused programmed cell death in 34 +/- 5.4% of the cells. Coincubation of PAF (10(-7)M) with alphaIgM led to a significant decrease in apoptotic cells as measured by DNA laddering and TUNEL assay (13.8 +/- 3%). The effect of PAF was dose dependent (10(-7)-10(-9) M) and was inhibited by the specific PAF receptor antagonist, WEB 2170. PAF protected cells from the effect of alphaIgM for up to 1 h after it was added. alphaIgM-induced programmed cell death in Ramos cells was blocked by catalase and, therefore, is caused in part by the production of toxic hydroxyl radicals from hydrogen peroxide. We investigated the action of PAF on markers of intracellular oxidation. H2O2 in low doses induced apoptosis, via production of OH. radicals. PAF inhibited H2O2-induced apoptosis in Ramos cells; it also attenuated H2O2- and alphaIgM-mediated increases in hydroxyl radical (OH.) as measured by the oxidation of 2',7'-dichlorofluorescein diacetate to 2',7'-dichlorofluorescein and blocked the depletion of reduced glutathione induced by alphaIgM. PAF maintained IgM secretion, which was greatly inhibited by incubation with alphaIgM alone. These data indicate that PAF potentially provides an important cosignal to surface IgM-stimulated Ramos cells by inhibiting apoptosis. This is in part due to the activity of PAF in the oxidant/ antioxidant pathway.