bluuebunny/crossref_metadata_2025_split huggingface dataset:
T cell development in CD8-/- mice. Thymic positive selection is biased toward the helper phenotype.
Authors: Bachmann M F , Oxenius A , Mak T W , Zinkernagel R M 
Published: December 2022

Abstract
The CD4 and CD8 molecules are involved in T cell differentiation and activation. Nevertheless, efficient thymic maturation of helper T cells has been shown in the absence of the CD4 molecule. These CD4-deficient helper T cells expressed alpha beta-TCR and were able to control Leishmania infections and to mediate Ab class switch. Using mice deficient for the CD8 alpha-chain, we investigated whether a similar cytotoxic T cell population was generated in the absence of the CD8 coreceptor. A CD8-deficient cytotoxic T cell population corresponding to the described CD4-deficient helper T cell population was virtually absent both functionally and physically. These results support the idea that thymic maturation is asymmetrical and strongly biased toward the helper phenotype.
Diverse VH and V kappa genes encode antibodies to Pseudomonas aeruginosa LPS.
Authors: Emara M G , Tout N L , Kaushik A , Lam J S 
Published: December 2022

Abstract
The molecular nature of the murine Ab response to Pseudomonas aeruginosa LPS was examined using a panel of 10 well-defined anti-LPS mAbs. Abs to P. aeruginosa LPS are encoded by diverse V-genes, with at least five VH and four V kappa gene families represented in these Abs. The Abs that bind to hydrophilic O-polysaccharide side chains of B-band LPS and A-band LPS are encoded by VH J558, SM7, and J606 gene families, while Abs to hydrophobic core and lipid A regions are encoded by X24, SM7, and Q52 gene families. All active JH and only two J kappa (J kappa 2 and J kappa 5) germ-line genes are utilized in the anti-LPS Abs examined. Four of six anti-P. aeruginosa mAbs used diversity genes of the DSP2 gene family. Interestingly, JH1 and JH2 use was observed in three mAbs that reacted with hydrophilic LPS epitopes (O-polysaccharide, A-band LPS), whereas JH3 and JH4 use was observed in three mAbs that bound to the more hydrophobic regions of LPS (core, lipid A). Point mutations were observed in framework and complementarity-determining regions (CDRs) of VH and VL genes, suggesting an Ag-driven maturation process in response to P. aeruginosa LPS. Mutations occurred in all heavy chain CDRs, as well as in CDR1 and CDR3 of the light chain, indicating an important role of these regions in binding to LPS. These data suggest that diverse VH and V kappa genes encode Abs to LPS from P. aeruginosa.
Comparative sequence analysis of cytokine genes from human and nonhuman primates.
Authors: Villinger F , Brar S S , Mayne A , Chikkala N , Ansari A A 
Published: December 2022

Abstract
Two major issues severely limit the studies of human recombinant cytokines/growth factors in nonhuman primates. First, assays and reagents specific for the detection and quantitation of human cytokines do not all function when utilized to detect/quantitate the nonhuman primate cytokines. Second, although most of the human cytokines appear to induce similar, if not identical, biologic function when used with cells from nonhuman primates in vitro or in vivo, they invariably induce Ab responses in vivo, precluding their repeated and/or continued use in vivo. Our laboratory has thus initiated studies to clone, sequence, and prepare recombinant cytokines from nonhuman primates and to define assays and reagents for their detection and quantitation at the nucleic acid and protein level. The data that were derived from such studies show that the nonhuman primate cytokines IL-1 alpha, IL-1 beta, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12 alpha, IL-12 beta, IL-15, IFN-alpha, IFN-gamma, and TNF-alpha share 93 to 99% homology at the nucleic acid and protein level with the human equivalents. The most prominent differences between human and nonhuman primate cytokine sequences were noted for IL-1 alpha/beta, IL-2, IL-8, IFN-alpha, IFN-gamma, and IL-12 beta. The aligned sequences of cytokines for human and several nonhuman primate species are provided herein, and a phylogenetic analysis of the published sequences of select cytokines from other species, along with those of the nonhuman primates, are described. In addition, comparative analysis of the relative bioactivity of our immunoaffinity-purified recombinant rhesus macaque IL-4, IL-15, and IFN-gamma with commercially available human recombinant cytokines is described herein.
Inhibition of gamma delta T cell recognition by receptors for MHC class I molecules.
Authors: Nakajima H , Tomiyama H , Takiguchi M 
Published: December 2022

Abstract
NK cells have receptors for MHC class I molecules that inhibit cytotoxicity against target cells. We show that recognition of gamma delta CTL is negatively regulated by receptors for MHC class I molecules. Cytolysis of C1R cells by gamma delta CTL clones was inhibited by the expression of polymorphic HLA class I molecules on target cells and was restored by blocking with anti-HLA class I mAb, suggesting the presence of inhibitory receptors for HLA class I molecules. The receptors for HLA class I molecules on gamma delta T cells were heterogenous. The immune responses to various Ags may be regulated via these inhibitory receptors on T cells and NK cells.
Persistence of V beta 6+ T cells in Mls-1a mice. A role for the third complementarity-determining region (CDR3) of the T cell receptor beta chain in superantigen recognition.
Authors: Chies J A , Marodon G , Joret A M , Regnault A , Lembezat M P , Rocha B , Freitas A A 
Published: December 2022

Abstract
We have studied V alpha 2 and J beta usage by V beta 6+CD4+ peripheral T cells isolated from the congenic mice strains BALB/c (Mls-1b) and BALB.D2 (Mls-1a). We found that the TCR beta-chain of V beta 6+CD4+ T cells present in adult Mls-1a mice differed from those in Mls-1b mice; the fraction of V beta 6+CD4+T cells using the J beta 2.7 segment was reduced, while the number of V beta 6+CD4+ T cells using J beta 1.2 was augmented. These results indicate that the CDR3 region of the TCR beta-chain participates in recognition of the Mls superantigen. We also found that in Mls-1a mice an increased fraction of V beta 6+CD4+ T cells expressed the V alpha 2 chain. The study of J beta usage by V beta 6+CD4+V alpha 2+ and V beta 6+CD4+V alpha 2- T cells indicates that both J beta segment and TCR V alpha 2 chain expression confer complementary protection against deletion by Mls-1a superantigen. These results suggest a novel view of Mls-1a-driven selection, where the CDR3 region of the V beta chain modulates superantigen recognition, and the affinity/avidity of the TCR-MHC-superantigen complex determine the fate of the T cell.
Gamma delta T cells in the pathobiology of murine acute graft-versus-host disease. Evidence that gamma delta T cells mediate natural killer-like cytotoxicity in the host and that elimination of these cells from donors significantly reduces mortality.
Authors: Ellison C A , MacDonald G C , Rector E S , Gartner J G 
Published: December 2022

Abstract
NK-like cytotoxicity in F1-hybrid mice with acute GVH disease is mediated by donor-derived CD3+/CD4-/CD8- cells that can lyse both NK-sensitive YAC-1 target cells as well as NK-resistant targets such as BW1100 and P815. Our objective was to determine whether this activity is mediated by gamma delta TCR+ cells. We showed that NK-like cytotoxic activity in the spleen and lymph nodes of mice with acute GVH disease could be depleted by indirect complement-mediated lysis using an Ab against gamma delta TCR. When purified NK1.1+ spleen cells that had been positively selected on a magnetic cell separator were used as effector cells, we found that NK-like cytotoxicity was mediated only by gamma delta TCR+ cells, suggesting that cells with NK-like activity are gamma delta TCR+/NK1.1+. We showed by flow cytometry experiments that coexpression of NK1.1 and TCR-gamma delta occurred on a large proportion of large granular lymphocytes in the spleens of GVH mice, but was not detectable in normal control mice. In GVH mice, fewer than 10% of small agranular NK1.1+ lymphocytes coexpressed NK1.1+ and gamma delta TCR+. On the basis of this hypothesis, we postulate that graft-derived large granular lymphocytes develop the NK1.1+/gamma delta TCR+ phenotype during the reaction, and that these cells play a role in the pathogenesis of acute GVH disease. We performed experiments to determine whether depletion of gamma delta T cells from donor mice affected the outcome of lethal GVH disease and found that there was a significant reduction in mortality.
IFN-gamma up-regulates the human C5a receptor (CD88) in myeloblastic U937 cells and related cell lines.
Authors: Burg M , Martin U , Rheinheimer C , Köhl J , Bautsch W , Böttger E C , Klos A 
Published: December 2022

Abstract
On human mature monocytes the immunomodulator IFN-gamma has been shown to down-regulate the receptor for the anaphylatoxic peptide C5a (CD88, C5aR). In this study, we show that in immature myelo-/monoblastic U937, HL60, and MonoMac6 cells, IFN-gamma induces C5aR-ligand binding activity. In U937 cells, this induction cannot be blocked by the protein kinase C inhibitor staurosporine. An increase in free cytosolic Ca2+ upon ligand binding indicates functional coupling of this receptor in U937 and HL-60 cells. G-Proteins involved in this C5a responsiveness after IFN-gamma induction are completely pertussis toxin sensitive. Our data suggest that an additional pertussis toxin-resistant pathway exists in U937 cells after induction by dibutyryl cAMP. However, this is not due to changes in the mRNA level of the pertussis toxin-insensitive G-protein subunit G alpha 16. Induction by dibutyryl cAMP, but not that by IFN-gamma, resulted in C5a-dependent release of N-acetyl-beta-D-glucosaminidase, further highlighting functional differences in the effects of the inducers. Our data show an IFN-gamma-dependent increase in C5aR expression and suggest a maturation-related change in signaling of the C5aR, presumably at the level of receptor coupling.
Regulation of the Fas lytic pathway in cloned CTL.
Authors: Glass A , Walsh C M , Lynch D H , Clark W R 
Published: December 2022

Abstract
Cloned murine CTL activated via the TCR or by PMA and ionomycin up-regulate surface Fas ligand and show an increased ability to kill non-Ag-specific Fas+ target cells. This up-regulation starts after 45 to 60 min and has a t1/2 for reversal of about 90 min. Up-regulation of lytic function is accompanied by up-regulation of Fas ligand on the CTL surface, which can be blocked by protein synthesis inhibitors. When up-regulation of Fas lytic function was induced by PMA and ionomycin, EGTA blocked both activation of lytic function and expression of Fas ligand detected by FACS analysis. However, when up-regulation was induced by specific Ag, EGTA blocked activation of lytic function, but not up-regulation of Fas ligand. Moreover, EL-4 cells have very high levels of surface Fas ligand, although they are not cytotoxic. Thus, expression of surface Fas ligand may be required, but not sufficient, for Fas-mediated lysis.
Specificity and degeneracy of minor histocompatibility antigen-specific MHC-restricted CTL.
Authors: Gundlach B R , Wiesmüller K H , Junt T , Kienle S , Jung G , Walden P 
Published: December 2022

Abstract
Random peptide libraries were employed to investigate the specificity of Ag recognition by H-3-specific, H-2K(b)-restricted CTL clones. The peptide libraries consist of octapeptides with one defined sequence position and mixtures of 19 amino acids (all proteinogenic amino acids except for cysteine) in the remaining seven sequence positions. The complete set of 152 peptide libraries includes all octapeptides possible with these amino acids. Responses of the CTL clones to these peptide libraries reveal patterns of preferred epitope amino acids. Depending on the CTL clone tested, varying numbers of different amino acids were identified for the different sequence positions indicating degeneracy of Ag recognition. Sequences for synthetic epitopes active at low pM concentrations could be deduced from these patterns. They confirm that TCRs of CTL clones do not exhibit specificity for unique ligand structures but rather can interact with sets of ligands. The sequences of peptides recognized by a single clone exhibit great sequence heterogeneity.
Sustained T cell receptor-mediated Ca2+ responses rely on dynamic engagement of receptors.
Authors: Hashemi B B , Slattery J P , Holowka D , Baird B 
Published: December 2022

Abstract
We have investigated the functional advantage of surface-attached ligands for TCR-mediated cell activation with flow cytometric measurements of cytoplasmic Ca2+ changes in T cells after aggregation of TCR by soluble and bead-attached mAb. Conjugation of HPB-ALL human leukemia cells with cell-sized beads coated with anti-TCR mAb causes a stronger, more sustained Ca2+ response than that produced by the soluble form of the same mAb. Addition of a large excess of the soluble mAb subsequent to stimulation with the beads causes a marked reduction in the response of the bead-conjugated cells, but only limited disruption of the conjugates. Free (nonconjugated) cells, sampled simultaneously in this mixture, respond to the soluble mAb with a transient Ca2+ increase that declines with the same kinetics as the bead-conjugated cells after addition of the soluble mAb. Fab fragments of the anti-TCR mAb cause a similar reduction in the response of the bead-conjugated cells, and they do not stimulate free cells. Following the Fab-mediated decline in cytoplasmic Ca2+ of conjugated cells to near-baseline concentrations, the addition of a second, noncompetitive, anti-TCR mab causes a Ca2+ response that is substantially reduced in magnitude compared with that for the free cells. The results indicate that soluble and surface-attached ligands cause TCR-specific desensitization of the Ca2+ response. Surface-attached ligands are more effective than soluble ligands in sustaining signaling in T cells at least in part because they facilitate steady association and/or reassociation of TCR into the bound state in the surface contact area.
Specific regulation of VLA-4 and alpha 4 beta 7 integrin expression on human activated T lymphocytes.
Authors: Hernández-Caselles T , Martínez-Esparza M , Lazarovits A I , Aparicio P 
Published: December 2022

Abstract
Modulation of VLA integrins was studied in several human T cell clones upon specific and nonspecific cellular activation. Human activated T lymphocytes down-regulated both alpha 4 beta 1 and alpha 4 beta 7 integrins upon specific recognition of alloantigens (cytotoxic T cells) or in the presence of Staphylococcus enterotoxin B (superantigen recognizing noncytotoxic T cells). In contrast, the expression of other membrane integrins, such as VLA-1 and VLA-5 integrins, was not modified. Down-regulation of alpha 4 beta 1 and alpha 4 beta 7 integrins was observed as early as 3 h after stimulation, lasted later than 72 h and was partially inhibited by cytochalasin D. Interestingly, neither target cells nor NK cells modulated CD49d expression after interaction with T cells of K562, respectively, suggesting that CD49d expression was linked to specific T cell activation. The down-regulation of the CD49d chain in T cell clones stimulated with immobilized anti-CD3 mAbs confirmed the role of TCR-mediated activation in CD49d regulation. However, the CD3-independent cellular aggregation induced by soluble anti-CD43 mAb was also able to strongly down-regulate alpha 4 beta 1 and alpha 4 beta 7. The present work shows the first evidence that CD49d subunit-bearing integrin expression is distinctly regulated from other integrins after Ag or superantigen recognition by human activated T cells. CD49d modulation may be relevant for the traffic and tissue localization of locally activated T cells during immune responses.
CD40 expressed on thymic epithelial cells provides costimulation for proliferation but not for apoptosis of human thymocytes.
Authors: Ruggiero G , Martinez Cáceres E , Voordouw A , Noteboom E , Graf D , Kroczek R A , Spits H 
Published: December 2022

Abstract
Human thymic epithelial cells express CD40, so we examined the possible role of CD40 in activation of thymocytes. We observed that both CD4+CD8- and CD4-CD8+ thymocytes proliferate after stimulation by anti-CD3 mAb in the presence of cultured thymic epithelial cells. Costimulation of CD4+ thymocytes by thymic epithelial cells is partly inhibited by an anti-CD40 mAb, but this mAb has no effect on costimulation of CD8+ thymocytes. The selective costimulatory ability of CD40 for CD4+ thymocytes was confirmed in experiments in which thymocytes were stimulated with anti-CD3 in the presence of murine P815 cells transfected with CD40 cDNA. The level of costimulation induced by P815-CD40 was comparable with that induced by P815 cells expressing CD80 (B7.1). Treatment of thymocytes with the Ca2+ ionophore ionomycin and the phorbol ester PMA or with anti-CD3 mAb resulted in up-regulation of the CD40 ligand, suggesting that this molecule is involved in CD40-mediated costimulation of human thymocytes. Costimulation of thymocytes by CD80 strongly increased anti-CD3-induced death of fetal thymocytes. In contrast, costimulation by CD40 did not increase anti-CD3-mediated apoptosis of these thymocytes. To confirm that CD40 does not affect anti-CD3-induced cell death, we established a variant of the Jurkat T leukemic cell line that constitutively expresses CD40L and analyzed the sensitivity of this cell line for activation-induced apoptosis. In contrast to CD80, CD40 failed to increase anti-CD3-mediated apoptosis in CD40L+ Jurkat cells, whereas both CD40 and CD80 strongly increased IL-2 production induced by anti-CD3. These findings suggest that costimulation by CD40 is involved in clonal expansion of CD4+ thymocytes but not in activation-induced cell death.
A DNA binding protein in human thymocytes recognizes the T cell receptor-delta-deleting element psi J alpha.
Authors: Verschuren M C , van Bergen C J , van Gastel-Mol E J , Bogers A J , van Dongen J J 
Published: December 2022

Abstract
The TCR is a heterodimeric molecule composed of either gamma delta or alpha beta chains. The differentiation mechanisms that force thymocytes into the gamma delta alpha beta lineage are poorly understood, but rearrangement processes in the TCR-delta alpha locus are likely to play an important role. The TCR-delta gene complex is flanked by the delta-deleting elements delta Rec and psi J alpha, which are assumed to delete the TCR-delta gene before V alpha-J alpha rearrangement. The nonproductive delta Rec-psi J alpha recombination occurs at high frequency in both fetal and postnatal immature thymocytes. To find DNA binding proteins involved in the delta Rec-psi J alpha preferential rearrangement, we performed electrophoretic mobility shift assays using the recombination signal sequence of psi J alpha with additional upstream and downstream sequences. We observed a 180-kDa DNA binding protein in nuclear extracts from human thymocytes that recognized a 46-bp binding site on the psi J alpha gene segment, containing the core motif GTTAATAGG. The psi J alpha binding protein, which we call PJA-BP, was also detected in immature CD3-T cell lines with TCR-delta genes deleted on both alleles, in a TCR-alpha beta+ cell line, and in two of four myeloid cell lines. This protein was absent in a TCR-gamma delta+ T cell line, in nonhemopoietic cell lines, and in all but one B cell lines tested. Although we could detect binding activity of the PJA-BP to some other TCR-J alpha gene segments, we postulate that binding of PJA-BP to the psi J alpha gene segment is one of the factors involved in the preferential delta Rec-psi J alpha gene rearrangement process.
Bias in the gamma delta T cell response to Listeria monocytogenes. V delta 6.3+ cells are a major component of the gamma delta T cell response to Listeria monocytogenes.
Authors: Belles C , Kuhl A K , Donoghue A J , Sano Y , O'Brien R L , Born W , Bottomly K , Carding S R 
Published: December 2022

Abstract
Despite extensive research, the role that gamma delta T cells play in the immune response to infectious disease has yet to be established. Here we report the generation of a mAb specific for the V delta 6.3 TCR and investigate the gamma delta+ and V delta 6.3+ T cell responses to the intracellular bacterium Listeria monocytogenes in BALB/c mice. By infecting animals with various doses of Listeria and analyzing the components of the cellular immune response at the two primary sites of infection, the liver and spleen, we have shown that the kinetics, composition, and magnitude of the gamma delta and V delta 6.3 T cell responses are dependent upon the injected dose of bacteria and the organ in which the infection is established. At low doses of infection, the gamma delta T cell response occurs late in the disease course, while at high doses, the response is earlier and of greater magnitude, particularly in the liver. At all infectious doses and in both tissues, the V delta 6.3+ population predominates and together with V delta 4+ cells composes the bulk of the gamma delta T cell response. Changes in the morphology of gamma delta+ and V delta 6.3+ cells at the site of infection are consistent with cellular activation and suggest that these cells are active participants in the Listeria-induced immune response. The results of our study suggest that many features of the gamma delta T cell response to Listeria are dose and tissue related.
Insight into the mechanism(s) through which TNF promotes the generation of T cell-mediated antitumor cytotoxicity by tumor bearer splenic cells.
Authors: Gorelik L , Bar-Dagan Y , Mokyr M B 
Published: December 2022

Abstract
We have shown previously that addition of TNF to stimulation cultures of MOPC-315 tumor bearer splenic cell suspensions containing metastatic tumor cells capable of secreting TGF-beta greatly enhances the generation of anti-MOPC-315 lytic activity by their CD8+ T cells. The current studies were undertaken to gain some insight into the mechanism(s) through which TNF potentiates the in vitro generation of anti-MOPC-315 cytotoxicity by such tumor bearer splenic cells. Here we show that TNF is capable of 1) preventing completely the inhibitory activity of TGF-beta for CTL generation when both cytokines are added at the time of initiation of a 5-day stimulation culture and 2) reversing at least part of the inhibitory activity of TGF-beta when TNF is added as late as 3 days after TGF-beta addition. The costimulatory molecule B7-2 is shown here to be important for the realization of the potentiating activity of TNF for CTL generation by tumor bearer splenic cells. However, despite the importance of the B7-2 molecule, TNF does not mediate its immunopotentiating activity for CTL generation through up-regulation in IL-2 production. In addition, we show here that GM-CSF, but not IL-12, is important for the potentiating effect of TNF for CTL generation by tumor bearer splenic cells. Taken together, these studies identify several factors that are important for the realization of the potentiating effect of TNF for the in vitro generation of antitumor cytotoxicity by tumor-infiltrated splenic cells. It is not known at present, however, whether these factors utilize distinct and/or overlapping mechanisms in realizing the TNF effect.