bluuebunny/crossref_metadata_2025_split huggingface dataset:
Insight into the mechanism of TCR-V beta 8+/CD8+ T cell-mediated MOPC-315 tumor eradication.
Authors: Mokyr M B , Prokhorova A , Rubin M , Bluestone J A 
Published: December 2022

Abstract
We have previously shown that depletion of TCR-V beta 8+ T cells by treatment with mAb reduces the curative effectiveness of low dose melphalan (L-phenylalanine mustard; L-PAM) for mice bearing a large MOPC-315 tumor and extensive metastases. Here we show that V beta 8+/CD8+ T cell lines derived from mice that are in the process of immune-mediated eradication of a large MOPC-315 tumor as a consequence of low dose L-PAM therapy (L-PAM TuB mice) are capable of mediating tumor eradication in vivo upon adoptive transfer. Analysis of the possible mechanisms through which these cell lines bring about tumor eradication revealed that the V beta 8+/CD8+ cells can exert in vitro a potent lytic activity and secrete large amounts of IFN-gamma. Both of these activities can be triggered by the MOPC-315 but not the MOPC-104E plasmacytoma and are restricted by the MHC class I H-2Kd molecule. In vivo neutralization of IFN-gamma by treatment with mAb was found to cause a noticeable delay in tumor rejection in mice subjected to adoptive chemoimmunotherapy with low dose L-PAM and V beta 8+/CD8+ cells; however, all tumors did regress after initial growth. Thus, the V beta 8+/CD8+ cells use an IFN-gamma-dependent mechanism for the realization of their in vivo tumor-eradicating immunity. However, an IFN-gamma-independent mechanism, most likely involving direct V beta 8+/CD8+ CTL activity, is apparently also used.
Role of sialic acid in the resistance of Trypanosoma cruzi trypomastigotes to complement.
Authors: Tomlinson S , Pontes de Carvalho L C , Vandekerckhove F , Nussenzweig V 
Published: December 2022

Abstract
Trypomastigotes of Trypanosoma cruzi, mammalian infective forms of the parasite, express an unusual cell surface trans-sialidase. This enzyme enables the parasite to rapidly sialylate its surface when supplied with alpha(2,3)-linked sialic acid from glycoconjugates in serum or on cell surfaces. Here we used a novel fluorescence-based, trypomastigote lysis assay to evaluate the role of sialic acid on the parasite's plasma membrane in providing protection against the complement cascade. Trypomastigotes were desialylated, and sialic acid removal was confirmed by a chemical assay and also by flow cytometry with the use of a mAb that recognizes a T. cruzi-sialylated epitope. Compared with sialylated trypomastigotes, which were completely refractory to lysis by human serum, only about 5% of the desialylated trypomastigotes were lysed by complement. However, further analysis revealed that the desialylated parasites had been resialylated during exposure to serum complement. Next we incubated desialylated trypomastigotes with samples of desialylated human serum. Although the sialidase-treated serum retained its full hemolytic activity, lysis of trypomastigotes increased only from 5 to 24%. This increase correlated with an enhanced deposition of complement protein C3 on the parasite surface. The ratio of C3b to lytically inactive iC3b was increased for desialylated, compared with sialylated, parasites. We conclude that although parasite sialic acid promotes C3b cleavage into iC3b, this mechanism alone does not account for the robust resistance of these parasites to complement lysis.
Identification of immunodominant epitopes in Trypanosoma cruzi trypomastigote surface antigen-1 protein that mask protective epitopes.
Authors: Wrightsman R A , Dawson B D , Fouts D L , Manning J E 
Published: December 2022

Abstract
The gene that encodes trypomastigote surface Ag-1 (TSA-1), a major surface Ag of the bloodstream trypomastigote stage of Trypanosoma cruzi, was expressed in a baculovirus expression system. To determine the epitope(s) in TSA-1 that was recognized during T. cruzi infection and after immunization with TSA-1, subregions of the TSA-1 gene were expressed in a bacterial expression system. As seen by Western blotting, both mice and rabbits immunized with recombinant TSA-1 protein, as well as T. cruzi-infected mice, developed strong immune responses to the carboxyl-proximal region of TSA-1, but show no reaction to the amino-proximal portion of TSA-1. When mice were immunized with either recombinant TSA-1 protein or the carboxyl-proximal region of TSA-1, they did not survive challenge with 10(3) bloodstream trypomastigotes. However, 70% of the mice immunized with the amino-proximal portion of TSA-1 survived challenge with 10(3) bloodstream trypomastigotes. Thus, the immune responses elicited by recombinant TSA-1 or the carboxyl-proximal portion of TSA-1 are nonprotective during T. cruzi infection. In contrast, vaccination with the amino proximal region of TSA-1 elicits a protective immune response. These results suggest that responses to immunodominant epitope(s) within the carboxyl-proximal portion of TSA-1 mask epitopes within the amino-proximal portion that are capable of stimulating host-protective immune responses. It is suggested that immunodominant regions in surface molecules such as TSA-1 may provide a mechanism for the parasite to evade the host immune response by directing the response away from epitopes that have the potential to elicit a reaction that is damaging to the parasite.
Monocyte chemotactic protein-2, monocyte chemotactic protein-3, and fibroblast-induced cytokine. Three new chemokines induce chemotaxis and activation of basophils.
Authors: Alam R , Forsythe P , Stafford S , Heinrich J , Bravo R , Proost P , Van Damme J 
Published: December 2022

Abstract
Cytokine-dependent mediator release from basophils and mast cells may play an important role in the pathogenesis of allergic and inflammatory conditions. Many C-C chemokines have been found to activate basophils and mast cells. We investigated the effect of three newly identified C-C chemokines, monocyte chemotactic protein-2 and -3 (MCP-2, MCP-3) and fibroblast-induced cytokine (FIC) on basophils and mast cells. We found that all three cytokines induced histamine secretion from basophils in a dose-dependent manner. The secretion of histamine was a Ca(2+)-dependent process. MCP-3 was the most potent activator of basophils. MCP-3 and FIC activated basophils from all study subjects, whereas the histamine release by MCP-2 was donor-dependent. The histamine-releasing activity of MCP-2, MCP-3, and FIC was compared with that of MCP-1, RANTES, and macrophage inflammatory protein-1 alpha using basophils from 10 donors. MCP-1 was the most potent among all the C-C chemokines. However, MCP-3 was nearly as potent. MCP-2, MCP-3, and FIC induced significant chemotaxis of basophils. None of the cytokines activated mouse peritoneal mast cells. The synthesis of mRNA for MCP-3 was investigated by reverse-transcription PCR using allergen-stimulated PBMC and bronchoalveolar lavage cells. Both MNC and bronchoalveolar lavage cells expressed mRNA for MCP-3. The results of this study indicate that MCP-2, MCP-3, and FIC are novel histamine-releasing factors.
Apoptotic neutrophils are phagocytosed by fibroblasts with participation of the fibroblast vitronectin receptor and involvement of a mannose/fucose-specific lectin.
Authors: Hall S E , Savill J S , Henson P M , Haslett C 
Published: December 2022

Abstract
The fate of neutrophils (PMNs) at sites of inflammation is important to our understanding of many disease processes. Previously, it had been widely assumed that extravasated PMNs inevitably disintegrated before their fragments were removed by local phagocytes, but we have recently described an alternative process whereby senescent PMNs undergo apoptosis (programmed cell death). This process leads to macrophage (Mphi) ingestion of the intact cell by a novel phagocytic recognition process. In this study, we show that monolayers of fibroblasts also can selectively phagocytose apoptotic PMNs and that the recognition of apoptotic PMNs by fibroblasts involves two distinct mechanisms: one uses the vitronectin receptor, as in Mphi ingestion of PMNs; the other uses a mannose/fucose-specific lectin, which plays no part in Mphi phagocytosis of apoptotic PMNs. The direct interactions between PMNs and fibroblasts demonstrated herein may have implications for our understanding of the relationship between inflammation and scarring in many diseases.
Inhibition of human peripheral blood lymphocyte function by protoporphyrin and longwave ultraviolet light.
Authors: Barrett K E , Yen A , Bigby T D , Montisano D , Gigli I 
Published: December 2022

Abstract
Modulation of immunologic effector cells by exogenous photoactive substances has been advanced as an underlying mechanism for the efficacy of various photochemotherapeutic regimens. It is also possible that endogenous photosensitizers, such as protoporphyrin, could similarly modify the function of immune cell types. We examined the effects of protoporphyrin plus longwave UV light on the ability of human PBL to proliferate in response to mitogens. Noncytotoxic dosages of protoporphyrin plus UV light suppressed PHA-stimulated proliferation of both PBMC and enriched T cells. CD8+ cells were more sensitive to this inhibitory effect than CD4+ cells. The inhibitory effect was also observed when proliferation was induced by the combination of a phorbol ester and ionomycin. Inhibition of PBMC proliferation was associated with inhibition of IL-2 secretion but proliferation was not restored with exogenous IL-2. Instead, the effect of protoporphyrin plus UV light may be on IL-2R. Cells treated with protoporphyrin and UV light did not display the increase in CD25 and the beta-chain of the IL-2R induced by PHA in control cells. In contrast to the effects of protoporphyrin and UV light on IL-2 and IL-2R alpha-chain protein expression, the accumulation of mRNA for these proteins induced by PHA was unaffected. None of the effects of protoporphyrin plus UV light on lymphocytes were observed in control experiments where cells were treated with either protoporphyrin or UV light alone. We conclude that biologically relevant dosages of protoporphyrin and UV light modify the function of circulating lymphocytes.
Idiotype- and anti-idiotype-reactive T lymphocytes in myasthenia gravis. Evidence for the involvement of different subpopulations of T helper lymphocytes.
Authors: Yi Q , Lefvert A K 
Published: December 2022

Abstract
Patients with myasthenia gravis have peripheral blood T cells that are stimulated to secrete IFN-gamma and IL-2 by human monoclonal anti-acetylcholine receptor and anti-idiotypic Abs. The human CD4+ Th cells may be subdivided into different subsets according to the pattern of cytokine production. To elucidate the subgroup of T cells involved in myasthenia gravis, we have analyzed IL-4-, IFN-gamma-, and IL-2-secretion patterns induced by two human disease-specific mAbs, one idiotypic and one anti-idiotypic Ab. T cells stimulated to secrete one or more of the cytokines were found in 33 of 34 patients. The idiotypic Ab stimulated IL-4 secretion in 19 of 34 patients, IFN-gamma secretion in 26 of 34 patients, and IL-2 secretion in 25 of 34. The anti-idiotypic Ab induced IL-4 secretion in 9 of 34 patients, IFN-gamma secretion in 29 of 34 patients, and IL-2 secretion in 28 of 34 patients. These T cell responses were MHC class II-restricted. According to the cytokine-secretion patterns, Id-reactive T cells might correspond to both Th1/Th2 and/or Th0 cells. The anti-idiotypic Ab more frequently induced a Th1-type response. This study indicates that different subsets of T lymphocytes are involved in the idiotypic network in myasthenia gravis, and that these functionally different T cells may participate in the immunoregulation of the disease.
The effect of mutant beta 2-microglobulins on the conformation of HLA-B27 detected by antibody and by CTL.
Authors: Fukazawa T , Hermann E , Edidin M , Wen J , Huang F , Kellner H , Floege J , Farahmandian D , Williams K M , Yu D T 
Published: December 2022

Abstract
The arthritis-predisposing HLA-B27 consists of a heavy chain, a small peptide, and the monomorphic beta 2-microglobulin (beta 2-m). CTLs and a mAb, Ye-2, which recognize the complex with specificities both for the heavy chain and for the peptide, are available. The beta 2-m is in noncovalent association with the heavy chain at multiple points and is exchangeable with free beta 2-m outside of the complex. The purpose of our experiments was to test whether mutant beta 2-m capable of modulating HLA-B27 activity could be created. Eighteen recombinant mutants of the human beta 2-m were experimentally generated. In 14 of these, mutations were at or near residues that are either contact residues or interface residues with the heavy chain. Relative to the parent beta 2-m, two-thirds of the mutants showed reduced ability to exchange into HLA-B27 complexes. However, at least four of them induced more than 80% decrease in Ye-2 Ab reactivity. Two mutants were able to induce a minor decrease in susceptibility to lysis by four CTL clones. One of the CTL clones was autoreactive. Two of the CTL clones were specific for HLA-B27 cells experimentally infected with arthritis-causing Yersinia enterocolitica. These results indicate that certain beta 2-m residues play an indirect role in peptide presentation, although they are not directly associated with the peptide residues.
Evidence for glycosphingolipid modification of the type 1 IFN receptor.
Authors: Ghislain J , Lingwood C A , Fish E N 
Published: December 2022

Abstract
P1-determinant glycolipids that include two membrane glycosphingolipids, globotriaosylceramide (Gal alpha 1-4Gal beta 1-4Glc-ceramide, Gb3) and galabiosylceramide (Gal alpha 1-4Gal-ceramide, Gb2) are receptors for an Escherichia coli-derived subunit toxin, verotoxin (VT-1). Studies with Daudi cells and glycosphingolipid-deficient Daudi mutants and U937 cells identified that the presence of Gb2/Gb3 correlates with IFN-alpha sensitivity. Comparison of amino acid sequences between VT-1 and the extracellular region of the 63-kDa IFN-alpha beta receptor (IFNAR) peptide reveals regions of identity, specifically in those domains in the VT-1 B subunit, that have been implicated as Gb2/Gb3 binding sites. In direct ligand binding studies, we show that membrane Gb2/Gb3 content affects the binding capacity of cells for IFN-alpha, although IFNAR cell surface expression is unaffected. Binding of IFN-alpha to the receptor leads to kinase-associated phosphorylation of the latent transcription factor, ISGF3, which activates transcription by binding to IFN-stimulated regulatory elements in IFN-sensitive genes. Electrophoretic mobility band shift assays indicated that U-937 and Daudi mutant cells, deficient in Gb2 and Gb3, exhibited reduced nuclear factor binding to the human 2-5A synthetase IFN-stimulated regulatory element when compared with wild-type Daudi cells, after exposure to IFN-alpha. Moreover, when Daudi cells were treated with a ceramide analogue, 1-phenyl-2-(decanoylamino)-3-morpholino-1-propanol, Gb2 and Gb3 synthesis was inhibited and a concomitant reduction in IFN-induced ISGF3 activation was noted. IFNAR cell surface expression was unaffected by 1-phenyl-2-(decanoylamino)-3-morpholino-1-propanol treatment. By using a fusion protein of the extracellular domain of IFNAR linked at the carboxyl terminus to the Fc portion of IgG1, we demonstrate that IFNAR is able to bind preferentially to Gb2. These results suggest that an association of IFNAR with membrane Gal alpha 1-4Gal containing glycolipids facilitates receptor-mediated signaling.
Activation of human monocytes via a non-neurokinin substance P receptor that is coupled to Gi protein, calcium, phospholipase D, MAP kinase, and IL-6 production.
Authors: Kavelaars A , Broeke D , Jeurissen F , Kardux J , Meijer A , Franklin R , Gelfand E W , Heijnen C J 
Published: December 2022

Abstract
Substance P (SP) is a tachykinin involved in the regulation of inflammatory processes. Tachykinins bind to three subtypes of neurokinin (NK) receptors. However, recently we demonstrated that monocytes express a SP binding site that is not one of the known NK receptors. Activation of this SP receptor leads to the stimulation of MAP kinase in monocytes. In the present paper we show that this novel SP binding site is coupled to a GTP binding protein of the Gi alpha 1/2 subclass. Triggering of the SP receptor leads to a rapid rise in cytosolic calcium. In a more sustained way, SP stimulates phospholipase D (PLD) activity in human monocytes. The effects of SP on calcium, PLD, and MAP kinase activity can be blocked by pretreatment of the cells with pertussis toxin, which is in agreement with receptor coupling to Gi. At a functional level, stimulation of the non-NK SP receptor on monocytes results in the induction of IL-6 production. We show here that the order of potency for activation of monocytes by various ligands is directly related to the Ki for displacement of labeled SP by these ligands. Therefore, our data strongly suggest that the effects of SP are mediated via the novel SP receptor we recently described.
Prevention of autoimmune type I diabetes in biobreeding (BB) rats by a newly established, autoreactive T cell line from acutely diabetic BB rats.
Authors: Nagata M , Yoon J W 
Published: December 2022

Abstract
An autoreactive T cell line, BNY-2, was established from lymphocytes isolated from the islets of acutely diabetic BioBreeding (BB) rats after continuous stimulation of the isolated lymphocytes by irradiated lymph node cells. Flow cytometric analysis showed that BNY-2 cells were positive for CD4 and CD5 and were negative for CD8 and RT6, indicating that these cells were phenotypically Th cells rather than cytotoxic T cells. mAbs against rat MHC class II Ags (anti-RT1.D) blocked the proliferation response of BNY-2 cells, suggesting that these cells recognize the MHC class II Du molecule. When splenic T lymphocytes from diabetes-prone BB rats were stimulated by Con A in the presence of irradiated BNY-2 cells or irradiated lymph node cells, the BNY-2 cells had a significant suppressive effect on splenic T cell proliferation, whereas lymph node cells had no effect. When we injected diabetes-prone BB rats i.v. at 30 and 60 days of age with activated BNY-2 cells, the incidence of diabetes was significantly reduced compared with that seen in saline-injected control rats (diabetic incidences were 12 and 80%, respectively). On the basis of these observations, we conclude that autoreactive BNY-2 T cells, established from the pancreatic islets of acutely diabetic BB rats, can prevent the development of autoimmune diabetes in the diabetes-prone BB rat by an immunosuppressive effect.
Clonotype analysis of peripheral blood T cells and autoantigen-reactive T cells from patients with mixed connective tissue disease.
Authors: Okubo M , Kurokawa M , Ohto H , Nishimaki T , Nishioka K , Kasukawa R , Yamamoto K 
Published: December 2022

Abstract
T cells that recognize autoantigens may play a central role in the autoimmune response. We have previously shown that autoantigen-reactive T cells (CD4+) to U1-small nuclear ribonucleoprotein A were found in the PBMC of patients with systemic lupus erythematosus or mixed connective tissue disease. To reveal clonotypes of such T cells that spread to the periphery, T cell clonal accumulations and their TCR-beta chain variable gene usages in fresh PBMC from eight patients with mixed connective tissue disease were analyzed by a new method of single strand conformation polymorphism applying to TCR gene detection. The results revealed that the numbers of accumulated T cell clones (mean: 24.3 clones) were greater than the numbers of clones detected in healthy donors (mean: 4.0 clones). Frequently used V beta genes in these accumulated T cell clones were V beta 1, 3, 4, 5.2, 14, and 16. After the stimulation for these samples with the soluble recombinant U1-small nuclear ribonucleoprotein A protein, proliferative T cell responses were observed. We found that T cell clones expressing more restricted TCR V beta genes (1, 3, 5.2, and 14 families) accumulated in vitro. These results suggest that autoantigen-reactive oligoclonal T cell accumulations are present in the peripheral blood from systemic autoimmune disease patients.
A region of the third variable loop of HIV-1 gp120 is recognized by HLA-B7-restricted CTLs from two acute seroconversion patients.
Authors: Safrit J T , Lee A Y , Andrews C A , Koup R A 
Published: December 2022

Abstract
HIV-1 envelope-specific CTL clones were isolated from the peripheral blood of two patients from within weeks of seroconversion. These clones were CD8+ and restricted by the HLA-B7 molecule. The minimum epitope recognized by the clones was determined to be the 30-amino acid (aa) sequence RPNNNTRKSI within the third variable (V3) loop of the envelope glycoprotein gp120. The aa sequence of this epitope is consistent with the motif found in naturally processed peptides eluted from HLA-B7 molecules. This region of the V3 loop is reasonably well conserved among clade B and some nonclade B isolates of HIV-1, especially at the anchor residues that determine binding to the HLA-B7 molecule. Using peptides based upon virus sequences present within each patient, we determined that autologous viruses were recognized by the clones, and we detected no escape variants from the initial clonal response during the acute phase of infection. Interestingly, a serine to arginine change at position 9 of the epitope abrogated clone recognition in one of the patients. This aa change is one factor that has been associated with a change from a nonsyncytium-inducing to a syncytium-inducing phenotype of HIV-1, raising the possibility that in HLA-B7-expressing patients, escape from this clonal CTL response and a change in viral phenotype may be linked. This study demonstrates that human CTL can be generated against sequences within the third variable loop of HIV-1 gp120. Because multiple vaccine strategies are based upon the V3 loop of HIV-1 gp120, this defined epitope can be exploited in determining the ability of certain vaccines to stimulate a CTL response in a select population of individuals.
Endothelial cell-induced resistance to cyclosporin A in human peripheral blood T cells requires contact-dependent interactions involving CD2 but not CD28.
Authors: Karmann K , Pober J S , Hughes C C 
Published: December 2022

Abstract
The ability of cultured human endothelial cells (EC) to activate resting T cells depends on signals provided by EC that augment T cell IL-2 synthesis. EC-mediated augmentation of IL-2 secretion by PHA-activated T cells is resistant to inhibition by cyclosporin A (CsA) or by ascomycin. Specifically, the 50% inhibitory dose of these drugs is increased over 100-fold in the presence of EC. Although rapamycin also inhibits IL-2 secretion, there is no effect of EC on the sensitivity of T cells to this drug. Resistance to CsA requires cell contact between the EC and T cells and develops 8 h after initiation of coculture. Experiments with blocking Abs implicate T cell CD2 and its endothelial cell ligands, both LFA-3 and CD59, but not T cell CD28 and its putative ligands, in EC-induced resistance to CsA. However, CD2 signals are not sufficient to induce resistance to CsA, and other EC signals remain to be identified. These observations suggest that interactions of graft EC with host T cells may contribute to CsA-resistant reactions in vivo.