bluuebunny/crossref_metadata_2025_split huggingface dataset:
Anergy and apoptosis in CD8+ T cells from HIV-infected persons.
Authors: Lewis D E , Tang D S , Adu-Oppong A , Schober W , Rodgers J R 
Published: December 2022

Abstract
CD8+T cells from HIV-infected persons increase early in infection, display increased levels of activation Ags, and abnormal MHC-restricted, HIV-specific and nonspecific cytotoxicity abilities. Paradoxically, these cells are also unresponsive to T cell signaling in vitro and have decreased in vitro cloning potential. HIV-specific CTL precursors also are lost late in infection. A quantitative Southern blotting technique showed that CD8+ T cells from asymptomatic, HIV-infected persons have increased DNA fragmentation after overnight incubation. DNA fragmentation was reduced by an endonuclease inhibitor but not by cycloheximide, suggesting that a pre-apoptotic state exists in vivo. Partial inhibition of DNA fragmentation also could be induced by IL-2 addition. No consistent difference in fragmentation was observed among CD8+ subpopulations from HIV-infected individuals, although only CD8+ T cells that did not express activation Ags (DR-, CD28+, CD57- phenotype) showed reduced fragmentation when incubated in IL-2. A dramatic increase in CD8+, CD28- cells was observed in asymptomatic HIV-infected people. A subset of CD8+, CD28- cells in both controls and HIV-infected people do not proliferate to T cell signals, and these cells from controls demonstrate increased DNA fragmentation in vitro after 3 days of incubation, regardless of stimulation conditions. This suggests that the cells are end-stage cells. Taken together, the data suggest an increase in anergic or apoptotic CD8+ T cells in HIV-infected persons. Eventual depletion of HIV-specific CD8+ T cells may occur through a process of proliferation, anergy induction, and apoptosis.
Arrested rearrangement of TCR V beta genes in thymocytes from children with X-linked severe combined immunodeficiency disease.
Authors: Sleasman J W , Harville T O , White G B , George J F , Barrett D J , Goodenow M M 
Published: December 2022

Abstract
Human X-linked severe combined immunodeficiency disease (SCID) is an immunodeficiency disorder in which T cell development is arrested in the thymic cortex. B lymphocytes in children with X-linked SCID seem to differentiate normally. X-linked SCID is associated with a mutation in the gene that encodes the IL-2R gamma-chain. Because TCR-beta gene recombination is a pivotal initial event in T lymphocyte ontogeny within the thymus, we hypothesized that a failure to express normal IL-2R gamma could lead to impaired TCR-beta gene recombination in early thymic development. PCR was used to determine the status of TCR-beta gene-segment rearrangements in thymic DNA that had been obtained from children with X-linked SCID. The initial step in TCR-beta gene rearrangement, that of D beta to J beta recombination, was readily detected in all thymus samples from children with X-linked SCID; in contrast, V beta to DJ beta gene rearrangements were undetectable in the same samples. Both D beta to J beta and V beta to DJ beta TCR genes were rearranged in the thymic tissues obtained from immunologically normal children. We conclude that TCR beta-chain gene rearrangement is arrested in children with X-linked SCID. Our results suggest a causative relationship between the failure of TCR beta-chain gene rearrangements to proceed beyond DJ beta rearrangements and the production of a nonfunctional IL-2R gamma-chain.
Activation of src family kinases in human pre-B cells by IL-7.
Authors: Seckinger P , Fougereau M 
Published: December 2022

Abstract
IL-7 was identified originally as a specific pre-B cell growth factor. We have investigated its signal transduction mechanism by using the human pre-B cell line Nalm-6, and have found that it stimulates tyrosine phosphorylation of various proteins: pp27, pp43, pp54, pp64, pp78, pp90, pp105, and pp120. Antiphosphotyrosine immunoprecipitates from IL-7-stimulated Nalm-6 showed two major proteins of M(r) = 60,000 and 55,000, capable of autophosphorylation. Autophosphorylation was maximal 10 min after the cells were challenged with the cytokine. Antiphosphotyrosine immunoprecipitates from IL-7-stimulated cells also increased tyrosine phosphorylation of the exogenously added substrate histone H2B. Furthermore, by using a polyclonal anti-IL-7 receptor (IL-7R) Ab in Western blotting analysis, we observed that antiphosphotyrosine immunoprecipitates were associated with the IL-7R in a transient manner. These data indicate that the IL-7R associates with tyrosine-phosphorylated proteins as its amino acid sequence is devoid of a putative site of tyrosine phosphorylation. These results were confirmed as several 32P-labeled proteins were visualized after immunoprecipitation by using anti-IL-7R Ab. Anti-IL-7R immunoprecipitates from IL-7-stimulated cells revealed a unique band of M(r) = 60,000 associated with the receptor able to autophosphorylate in the presence of ATP and Mn2+. Hence, we identified p59fyn and p53/56lyn to be stimulated by IL-7. In contrast to p53/56lyn, p59fyn was found to be associated constitutively with the cloned IL-7R. These data emphasize the role of the src family in hematopoiesis.
TGF-beta 1 is a potent inducer of human effector T cells.
Authors: Cerwenka A , Bevec D , Majdic O , Knapp W , Holter W 
Published: December 2022

Abstract
TGF-beta 1 is known to modulate lymphocyte activation affecting cell proliferation and the production of cytokines and Igs. Little is known about the characteristics of T cells grown in the presence of TGF-beta 1. We have stimulated human T cells with PHA in the presence of TGF-beta 1 under serum-free conditions for 7 days and characterized the resulting cell population. TGF-beta 1 (0.0032 to 10 ng/ml) affected neither [3H]thymidine incorporation (day 4) nor cell yield (day 7) in these cultures. However, cells activated in the presence of TGF-beta 1 proliferated vigorously in secondary cultures and produced highly elevated amounts of IL-2 (12 +/- 3-fold enhancement of IL-2 production in response to CD2 plus CD28 stimulation compared with control cells, mean +/- SEM; n = 10). The enhancing effects of TGF-beta 1 were demonstrable over a wide range of concentrations (0.4 to 10 ng/ml). The increased IL-2 protein production was paralleled by a dramatic up-regulation of IL-2 mRNA. In addition, cells precultured with TGF-beta 1 responded with enhanced cluster formation in the secondary cultures. With regard to their phenotype, we observed an increased expression of the alpha E beta 7-integrin human mucosal lymphocyte-1 and of the CD2-restricted epitope CD2R, whereas the expression of CD11a was slightly decreased. In contrast, TGF-beta 1 did not influence the constitutive or activation-induced expression of CD4, CD8, CD45RA, CD45RO, CD25, CD71, CD54, CD58, CD59, and B7. We conclude that TGF-beta 1 supports the generation of human effector cells with a strongly enhanced capacity to respond to subsequent restimulation.
Cloning and molecular characterization of mouse bcl-x in B and T lymphocytes.
Authors: Fang W , Rivard J J , Mueller D L , Behrens T W 
Published: December 2022

Abstract
We report the cloning and initial characterization of the mouse homologues of the bcl-2-related gene, bcl-x. We compare these to the two major isoforms of human bcl-x that were previously identified, bcl-xLong (bcl-xL) which has death repressor activity similar to bcl-2, and bcl-xShort (bcl-xS), an alternative mRNA splice product that deletes a highly conserved domain shared by bcl-2 family members and promotes cell death in transfection studies. In addition to murine (m) bcl-xL and mbcl-xS, we have cloned a novel cDNA isoform that we designate mbcl-x delta TM. This cDNA deletes, by means of alternative splicing, the carboxy terminal transmembrane domain of bcl-x and is predicted to be a soluble, rather than membrane-bound, protein. We found that mbcl-x mRNA is highly inducible in splenocytes stimulated with either anti-CD3 Abs or LPS/dextran sulfate, and that the major species of mbcl-x mRNA in a variety of cell lines and tissues was the xL isoform. Transfection of mbcl-xL or mbcl-xS into Hela cells resulted in targeting primarily to mitochondria, whereas mbcl-x delta TM localized diffusely throughout the cytosol. Overexpression of the novel delta TM isoform in an IL-3-dependent cell line delayed the onset of apoptosis induced by growth factor withdrawal. Thus, a naturally-occurring form of mbcl-x present in lymphocytes that does not localize to the mitochondrial membrane is functional in preventing apoptotic cell death. Moreover, these data suggest that bcl-x provides a life signal in activated lymphocytes.
Invariant-cognate peptide exchange restores class II dimer stability in HLA-DM mutants.
Authors: Monji T , McCormack A L , Yates J R , Pious D 
Published: December 2022

Abstract
Class II presentation mutants have mutations in the HLA-DMA or B genes and are defective in the presentation of whole exogenous Ags restricted by HLA-DR, -DQ, and -DP. The functional defect in Ag presentation is accompanied by an altered conformation of cell surface class II molecules and instability of extracted class II dimers in SDS-PAGE; the latter can be corrected by incubation of mutant cells in an acidic pH in the presence of cognate peptide. Here we investigated the basis for correction of class II dimer instability by acid/cognate peptide treatment and the extent to which this treatment corrects the class II conformational defect in DMB mutants. We found that an acidic pH generates peptide binding sites in class II molecules of DMB mutants by eluting invariant chain (li)-derived peptides from them. Cognate peptides can then bind to the empty binding sites of class II molecules in a pH-independent manner, which results in stabilization of class II dimers. Acid/peptide treatment also restores the DR polymorphic epitope recognized by mAb 7.3.19.1 but not the DR polymorphic epitope recognized by mAb 16.23; low pH gradually destroys the 16.23 epitope in nonmutant cells. Mutant 10.24.6, which has a mutation in the DRA coding region creating an extra glycosylation site, also has unstable DR dimers whose stability is restored by acid/peptide treatment. These results suggest that the primary phenotypic defect in both the DMB and 10.24.6 mutants is the abundance of li peptides and lack of cognate peptides bound to class II molecules.
CD8+ T lymphocyte-mediated lysis of Chlamydia-infected L cells using an endogenous antigen pathway.
Authors: Beatty P R , Stephens R S 
Published: December 2022

Abstract
Intracellular bacterial pathogens have evolved to either grow in the nutrient-rich cytoplasm or remain sequestered within a vacuole. One potentially important selective advantage for growth within a vacuole may be evasion of cell-mediated detection and cytolysis. To address this question we used the endosomally confined bacterium Chlamydia trachomatis, which naturally infects epithelial cells, to examine CTL-mediated lysis of nonphagocytic cells. CTL-mediated lysis of infected target cells was detected, although the increased expression of ICAM-1 by transfection was required. The elimination of CD8+ T cells or addition of brefeldin A or cycloheximide eliminated specific cytolysis, whereas conversely, treatment with chloroquine or ammonium chloride had only minor effects. These results implicate endogenous Ag processing for Chlamydia-specific cytolysis. This work demonstrates CTL-mediated lysis of cells infected with an intracellular bacterium that inhibits lysosomal fusion and is confined to an endosomal vacuole.
Toxoplasma gondii oral infection induces specific cytotoxic CD8 alpha/beta+ Thy-1+ gut intraepithelial lymphocytes, lytic for parasite-infected enterocytes.
Authors: Chardès T , Buzoni-Gatel D , Lepage A , Bernard F , Bout D 
Published: December 2022

Abstract
The first line of defense of the host after primary infection by Toxoplasma gondii is the intestinal mucosal surface, which consists of epithelial cells, intraepithelial lymphocytes (IEL) (mainly of CD8 phenotype), mucus, and secretory Igs. T. gondii cysts were administered orally to CBA/J mice to determine whether parasite-specific cytotoxic IEL can be elicited within the intestine. We found that oral infection led to an increase in the relative percentages of the CD8 beta + and Thy-1+ IEL populations between day 9 and day 13 after infection. At these times, T. gondii-primed, but not control mice, generated parasite-specific cytotoxic effector IEL for toxoplasma-infected macrophages. This cytotoxic activity was genetically restricted. By using magnetically activated cell sorting, the effector IEL were shown to be CD8 alpha/beta + Thy-1+ T lymphocytes and FACScan analysis revealed that they mainly express TCR-alpha beta. A significant level of cytotoxicity was also observed against T. gondii-infected epithelial cells from the MODE-K cell line, suggesting that parasite-specific IEL may ensure epithelial integrity by rapidly killing infected enterocytes. Finally, toxoplasma stimulation in vitro led to IFN-gamma production by T. gondii-primed IEL. Taken together, these data suggest that antigen-specific IEL, bearing the CD8 alpha/beta + Thy-1+, TCR-alpha beta + phenotype, can act directly as effector cells through a specific CTL activity at the intestinal level and may indirectly activate other mucosal effector mechanisms through IFN-gamma secretion.
IL-2 can support growth of CD8+ T cells but not CD4+ T cells of human IL-2 receptor beta-chain transgenic mice.
Authors: Asano M , Ishida Y , Sabe H , Kondo M , Sugamura K , Honjo T 
Published: December 2022

Abstract
We have generated transgenic mice expressing the human (h) IL-2R beta-chain on lymphoid cells under the control of the mouse H-2Kd promoter. Spleen cells and thymocytes of the transgenic mice were cultured in the presence of 5 nM hIL-2. After a 10-day culture, the expanded populations were analyzed by flow cytometry and shown to be composed of CD8+ T cells and gamma delta T cells. Surprisingly, CD4+ T cells of the transgenic mice did not proliferate in response to hIL-2, although the CD4+ T cells expressed the transgenic hIL-2R beta-chain as well as the endogenous gamma-chain on their surface and bound 125I-labeled IL-2. When CD4+ T cells of the transgenic mice were stimulated with anti-CD3 mAb, the CD4+ T cells proliferated in response to hIL-2. These findings suggest that CD4+ T cells may require another triggering signal to respond to IL-2 even when IL-2Rs are expressed. By contrast, CD8+ T cells and gamma delta T cells respond to IL-2 as long as IL-2Rs are expressed.
Regulation of adhesion molecule expression by CD8 T cells in vivo. II. Expression of L-selectin (CD62L) by memory cytolytic T cells responding to minor histocompatibility antigens.
Authors: Mobley J L , Rigby S M , Dailey M O 
Published: December 2022

Abstract
Activation of murine T cells by Ag or mitogens results in changes in the expression of several cell-surface adhesion molecules that alter the way in which these cells migrate and localize in tissues in vivo. As naive CD8 precursor cells in lymph nodes (LN) differentiate into effector CTL in response to a skin allograft, they up-regulate their expression of Pgp-1 (CD44), VLA-4, and LFA-1 (CD11a/18), while down-regulating L-selectin (CD62L). All cytolytic activity is therefore present in this minor population of L-selectin- Pgp-1high LN T cells. We now report that, late after rejection of minor histocompatibility Ag-disparate skin grafts, the majority of memory CD8 T cells express both L-selectin and Pgp-1 and thus would be expected to migrate via the classical route of recirculation through LN. Furthermore, restimulation of these memory cells by Ag causes them to down-regulate L-selectin, so that memory-effector cells have the same L-selectin- Pgp-1high phenotype as do primary effector cells. These results are in contrast to recent reports that murine and ovine CD4 memory cells do not express L-selectin or recirculate through LN high endothelial venules. In addition, although virgin and naive CD4 cells may be divided based upon their expression of CD45RA or CD45RB, memory CD8 cells cannot be differentiated by their expression of CD45 isoforms.
An efficient Th2-type memory follows CD8+ lymphocyte-driven and eosinophil-mediated rejection of a spontaneous mouse mammary adenocarcinoma engineered to release IL-4.
Authors: Pericle F , Giovarelli M , Colombo M P , Ferrari G , Musiani P , Modesti A , Cavallo F , Di Pierro F , Novelli F , Forni G 
Published: December 2022

Abstract
A retroviral infection was used to introduce the cDNA coding for mouse IL-4 into the parental cells of a spontaneous adenocarcinoma of BALB/c mice (TS/A-pc). Four clones releasing between 5 to 40 U of IL-4 (10(5) cells) in 48 h culture were selected. The secretion of IL-4 does not affect their in vitro growth, whereas their ability to form tumor in vivo inversely correlates with the amount of IL-4 secreted. Although morphologic observation suggested that the rejection of clone D5.40 cells (releasing 40 U of IL-4) depends on eosinophil cytolysis, lymphocyte depletion experiments showed that this required CD8+ lymphocyte guidance. Mice that had rejected D5.40 cells were immune to a subsequent challenge with TS/A-pc. This memory rests on the interaction between noncytotoxic lymphocytes, eosinophils, and IgG1 and IgE anti-TS/A Abs. Comparison of these memory mechanisms with those elicited by IL-2 gene-transduced TS/A cells shows that the kind of cytokine released by the tumor cells determines the type of response. This Th2 memory seems to be more efficient in protecting against a subsequent challenge of TS/A-pc than the Th1-type memory elicited by IL-2 gene-transduced TS/A cells.
Monoclonal antibodies detect different distribution patterns of IL-8 receptor A and IL-8 receptor B on human peripheral blood leukocytes.
Authors: Chuntharapai A , Lee J , Hébert C A , Kim K J 
Published: December 2022

Abstract
mAbs previously reported to be specific for IL-8R type A (IL-8R-A) and mAbs specific for IL-8R type B (IL-8R-B), which are described in this paper, were used to investigate the expression of each receptor on various types of cells. We generated mAbs specific for IL-8R-B, 4D1, and 10H2 by immunizing mice with 293 cells that expressed IL-8R-B and by selecting hybridoma cell lines that secreted mAbs that bind to human neutrophils. Flow cytometry showed that mAbs 4D1 and 10H2 were specific for IL-8R-B, as determined by their exclusive binding to 293-27 cells that expressed IL-8R-B, but not to 293-71 cells that expressed IL-8R-A. Epitopes recognized by these IL-8R-B-specific mAbs were shown to be within the N-terminal residues 1-18 of the IL-8R-B on the basis of their binding to various N-terminal peptides, as measured by ELISA. These IL-8R-B-specific mAbs were able to inhibit up to 90 and 50% of the 125I-labeled IL-8 binding to 293-27 cells and human neutrophils, respectively. The combination of mAb 9H1 (anti-IL-8R-A) and mAb 10H2 (anti-IL-8R-B) inhibited approximately 70% of 125I-labeled IL-8 binding to human neutrophils. Flow cytometry showed a wide range of donor variation in the expression levels of IL-8R-A and IL-8R-B on various human peripheral blood leukocytes. All neutrophils, all monocytes, and 5 to 25% of total lymphocytes (CD8+ T cells and CD56+ NK cells) expressed IL-8R. Neutrophils expressed the highest level of both IL-8R-A and IL-8R-B, at an approximately equal ratio, whereas monocytes and IL-8R+ lymphocytes expressed higher levels of IL-8R-B than IL-8R-A. Double-color flow cytometric analysis showed that 7 to 42% of CD8+ T cells and 39 to 76% of CD56+ NK cells, but no CD 20+ B cells or CD4+ T cells, expressed IL-8R.
A transcription factor with AP3-like binding specificity mediates gene regulation after an allergic triggering with IgE and Ag in mouse mast cells.
Authors: Jarmin D I , Kulmburg P A , Huber N E , Baumann G , Prieschl-Strassmayr E E , Baumruker T 
Published: December 2022

Abstract
Mast cells are an important source of a number of lymphokines and chemokines primarily those released after challenge with the allergic trigger IgE and Ag. However, the mechanisms of lymphokine and chemokine gene activation in this cell type, as opposed to the mechanisms of activation in T cells, are poorly understood. As a model system, we addressed this issue in mast cells by using the recently cloned chemokine MARC gene, which belongs to the RANTES/sis gene family. After allergic stimulation, MARC induction is pronounced and mast cell specific. Northern blot analysis, in combination with two inhibitors, actinomycin D and cycloheximide, resulted in the formation of our initial hypothesis, which was that both transcriptional and post-transcriptional regulation are involved after stimulation through the Fc epsilon R. We performed a detailed promoter analysis of the cloned MARC gene by using transient assays of transfected reporter gene constructs. Thereby, two potential promoter regions were identified as being crucial for transcriptional stimulation. Additional fine mapping of the proximal element and subsequent electrophoretic mobility shift assays, combined with competitions of known transcription factor binding sites, identified one of the transcription factors in stimulated mast cells as an AP3 or AP3-like binding activity.
Regulation of intestinal epithelial barrier function by TGF-beta 1. Evidence for its role in abrogating the effect of a T cell cytokine.
Authors: Planchon S M , Martins C A , Guerrant R L , Roche J K 
Published: December 2022

Abstract
Maintenance of the integrity of the single-cell-thick intestinal epithelium as an in vivo barrier between environmental Ags and mucosal immunocytes is pivotal for health. The T cell cytokine IFN-gamma consistently disrupts this epithelial barrier in vitro, but the substances in mucosa that may be responsible for sustaining or enhancing barrier function have not been clearly identified. Therefore, we characterized the effect on the epithelial barrier of TGF-beta 1 and three prominent neuropeptides (VIP, substance P, somatostatin) by using a model system in which barrier function of a mature polar human colonic epithelial (T84) cell monolayer is reflected in 1) the electrical potential difference across the apical to basolateral surface of each cell, 2) the transmonolayer permeability to macromolecules such as horseradish peroxidase, and 3) lactate dehydrogenase release into the medium indicating epithelial cell cytolysis. Whereas T84 monolayers exposed to TGF-beta 1 alone demonstrated a modest increase in electrical resistance and barrier integrity, TGF-beta 1 showed a striking ability to reduce the capacity of IFN-gamma to disrupt epithelial barrier function. Characterization studies demonstrated that this TGF-beta 1 effect was prolonged (e.g., days) after a single exposure, progressive over the dose range 0.1 to 2.5 ng/ml, reversible with increased concentrations of IFN-gamma, and more pronounced when TGF-beta 1 exposure was to basolateral rather than to apical epithelial membranes. Macromolecular (horseradish peroxidase) penetration of epithelium was not simultaneously altered by TGF-beta 1 and epithelial cellular injury was minimal as gauged by lactate dehydrogenase release. Additional studies using a human pathogen demonstrated that TGF-beta 1 delayed and decreased the barrier disruption caused by exposure to Cryptosporidium parvum. TGF-beta 1 may be the first of a new class of cytokines that maintains and/or enhances barrier function of human enterocytes, in part by countering the effect of a T cell cytokine.