bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modulation of the intracellular Ca2+ and inositol trisphosphate concentrations in murine T lymphocytes by the glycosylphosphatidylinositol-anchored protein sgp-60.
Authors: Maschek B J , Zhang W , Rosoff P M , Reiser H 
Published: December 2022

Abstract
Stimulation of T lymphocytes via the TCR/CD3 complex initiates a series of intracellular biochemical events. Among the earliest cellular responses are the stimulation of the turnover of phosphatidylinositol and an increase in the intracellular Ca2+ concentration. The significance of these second messengers for distal cellular responses such as lymphokine production or cell proliferation is not understood. We have previously shown that hamster mAb to the murine glycosylphosphatidylinositol-anchored protein sgp-60 can inhibit IL-2 production, IL-2R expression, and cell proliferation, events normally observed after stimulation of T cells with an antibody to the TCR/CD3 complex or with the lectin Con A. We now show that the anti-sgp-60 mAb inhibits the activation-induced increase in intracellular Ca2+ concentration. Additional analysis demonstrates that the mAb interferes with the release of Ca2+ from intracellular stores and with the generation of inositol 1,4,5-trisphosphate. Our findings suggest a role for this glycosylphosphatidylinositol-anchored protein in the generation of second messengers in signal transduction through the TCR/CD3 complex in murine T lymphocytes.
Staphylococcus aureus Wood 46 strain activates human B cells without affecting DNA synthesis or tyrosine phosphorylation.
Authors: Saiki O , Kawamoto M , Fukuzumi M , Kanou M , Utsumi S 
Published: December 2022

Abstract
Induction of Ig secretion in human tonsilar B cell by protein A-deficient Staphylococcus aureus WOOD 46 strain (SAW) was examined. SAW induced as much Ig secretion as protein A-rich S. aureus Cowan I strain (SAC) when IL-2 was present in the culture. Activated and resting B cells are separated by Percoll gradient to determine whether SAW stimulates either resting or activated B cells. In resting B cells, SAW plus IL-2 induced IgM secretion significantly, but neither IL-2 nor SAW alone induced IgM secretion. In activated B cells, however, IL-2 induced IgM secretion by itself and SAW plus IL-2 did not induce additional IgM secretion. These results suggest that SAW activates small resting B cells rather than preactivated B cells. Subsequently, mechanisms of B cell activation by SAW and SAC were compared. SAW did not induce [3H]-TdR incorporation through day 1 to 5, and the number of viable cells was not increased by SAW stimulation. Moreover, SAW did not induce significant tyrosine phosphorylation at any concentration tested, when tyrosine phosphorylation of B cells was examined. However, SAC induced both [3H]-TdR incorporation and tyrosine phosphorylation of B cell efficiently. In further experiments, induction of IL-2R and IgM mRNA expressions were examined. SAW by itself induced IL-2R and IgM mRNA expressions without affecting expression of membrane-type IgM mRNA. These results show that SAW activates human B cells in quite a different manner from SAC by up-regulating the expression of secretory type IgM mRNA without affecting cell proliferation nor tyrosine phosphorylation, proposing a distinct B cell activation model from SAC.
Inhibition of murine T cell activation by cholera toxin B subunit is not mediated through the phosphatidylinositol second messenger system.
Authors: Woogen S D , Turo K , Dieleman L A , Beagley K W , Elson C O 
Published: December 2022

Abstract
Although cholera toxin B subunit is a potent mucosal immunogen in vivo, its predominant effect in vitro is inhibition of T cell and B cell activation. We reported earlier that this inhibition was not mediated through activation of adenylate cyclase and increases in intracellular cAMP. There is increasing evidence that T cell activation is initiated through the phosphatidyl inositol second messenger system in which phosphatidyl inositol bisphosphate is hydrolyzed by phospholipase C, producing inositol trisphosphate (IP3) and diacylglycerol. IP3 increases cytosolic calcium and diacylglycerol binds, translocates, and activates protein kinase C (PKC). These signals lead to a complex series of events eventuating in activation of a number of genes important in cell proliferation. In this study, we asked whether the mechanism of T cell inhibition by B subunit of cholera toxin (CT-B) was due to interference with the phosphatidyl inositol second messenger system. We found that substitution of ionomycin and PMA for IP3 and diacylglycerol, respectively, in culture induced T cell proliferation but only if both were present simultaneously. Such proliferation was inhibited by CT-B even if added hours after the start of culture. An assay for cytosolic PKC activity demonstrated that PMA translocation of PKC from cytosol to membrane was not inhibited by CT-B, indicating that CT-B does not inhibit activation of PKC. There was no inhibition of Con A-stimulated T cell phosphoinositol turnover. Moreover, Con A added to Fura-2 AM-loaded cells caused a rapid rise in cytosolic calcium, which CT-B preincubation did not alter. These results indicate that CT-B did not inhibit IP3 generation or action. We next looked at expression of genes involved in T cell proliferation. CT-B inhibited the production of IL-2 by mitogen-activated T cells; Northern analysis showed that this inhibition was associated with decreased levels of IL-2 mRNA. Expression of IL-2R and of transferrin receptors was only modestly reduced. Despite the presence of IL-2R on the T cells exposed to CT-B, the addition of exogenous IL-2 to the cultures did not reverse the CT-B-induced T cell inhibition. We conclude that the T cell inhibition by CT-B is not mediated by interference with the activation of the phosphatidylinositol second messenger system but occurs at a later stage of T cell activation.
Regulation of MHC class I and beta 2-microglobulin gene expression in human neuronal cells. Factor binding to conserved cis-acting regulatory sequences correlates with expression of the genes.
Authors: Drew P D , Lonergan M , Goldstein M E , Lampson L A , Ozato K , McFarlin D E 
Published: December 2022

Abstract
MHC class I molecules are coexpressed with beta 2-microglobulin (beta 2-M) on many somatic cells. However, these proteins are normally not present on cells of the central nervous system (CNS). Cells derived from human neuroblastomas were used as a model for investigating the molecular basis for the paucity of MHC class I and beta 2-M gene expression in neural cells and for the induction of these genes by two cytokines, IFN-gamma, and TNF-alpha. These cytokines independently increased MHC class I and beta 2-M cell surface expression on the neuroblastoma cell lines. IFN-gamma or TNF-alpha also increased MHC class I and beta 2-M steady-state RNA levels and the expression of MHC class I and beta 2-M CAT reporter constructs transiently transfected into the neuroblastoma cell lines, indicating that the cytokines acted by increasing the transcription of these genes. MHC class I and beta 2-M genes share two conserved regulatory elements, an NF kappa B-like site and the IFN consensus sequence, that act as a constitutive enhancer and an IFN-responsive element, respectively. Low MHC class I and beta 2-M gene expression in these cells was accounted for by undetectable to low factor binding activity specific for the above regulatory elements of these genes. TNF-alpha increased factor binding activity specific for the NF kappa B-like elements and IFN-gamma increased factor binding activity specific for the IFN consensus sequence elements of the MHC class I and beta 2-M genes, but not vice versa. Taken together, our results indicated that IFN-gamma and TNF-alpha increased MHC class I and beta 2-M gene expression in the neuroblastoma cell lines by inducing factor binding to the regulatory elements present in both genes.
Endogenous Ig production in mu transgenic mice. II. Anti-Ig reactivity and apparent double allotype expression.
Authors: Imanishi-Kari T , Huang C A , Iacomini J , Yannoutsos N 
Published: December 2022

Abstract
In 17.2.25 mu transgenic mice (M54, M95), many of the expressed Ig, whether encoded by the transgene or endogenous H chain genes, react with Ig. IgM antibodies encoded by the 17.2.25 mu transgene transfected into J558L myeloma cells are also Ig reactive. In addition, anti-Ig reactivity was manifested by antibodies of the IgM, IgG, and IgA isotypes from the transgenic mice, suggesting that this characteristic reactivity is associated with VH and VL domains of these antibodies. These antibodies bind the (Fab')2 fragment of mouse IgG1 mAb known to be directed against C mu allotypic determinants. This finding could account for the so called "double producer" B cells found in mu transgenic mice and previously identified in serologic assays conducted with two different anti-mu allotypic reagents. In transgenic mice, a high frequency of the antibodies encoded by the transgene or endogenous H chain genes react with polyclonal and monoclonal antiidiotypic antibodies raised against the 17.2.25 Id. The idiotypic and/or antiidiotypic reactivity displayed by antibodies derived from these transgenic mice is similar to that of antibodies expressed by neonatal B cells of normal mice. Thus, our data suggest that transgene expression can play an important role in shaping the endogenous repertoire of antibody specificities.
A monoclonal antibody produced during infection which recognizes an epitope of influenza hemagglutinin only in the context of H-2k MHC class I antigen.
Authors: McLain L , Dimmock N J 
Published: December 2022

Abstract
A hybridoma prepared from cells isolated from the lungs of H-2k mice infected with influenza virus (A/WSN) produces a monoclonal IgM (LM41) which recognizes an epitope of the A/WSN hemagglutinin (HA) Ag only when it is expressed in H-2k cells, as shown by Ag binding and complement-mediated lysis. However, it did not bind to the native HA of virus particles or any form of HA protein present on A/WSN-infected H-2d cells. LM41 inhibited Ag-specific, MHC class I-restricted lysis of H-2k target cells infected with a vaccinia recombinant virus expressing the HA of A/WSN by CTL from A/WSN virus-infected H-2k mice. We conclude that LM41 has a similar Ag specificity to the HA-specific TCR.
Changes in mechanisms of monocyte/macrophage-mediated cytotoxicity during culture. Reactive oxygen intermediates are involved in monocyte-mediated cytotoxicity, whereas reactive nitrogen intermediates are employed by macrophages in tumor cell killing.
Authors: Martin J H , Edwards S W 
Published: December 2022

Abstract
Freshly isolated human blood monocytes were spontaneously cytotoxic toward K562 tumor cells. During culture of the monocytes in vitro cytotoxicity decreased during the first 48 h but tumoricidal competence was restored after 3 to 4 days in vitro. These changes were accompanied by changes in both reactive oxygen intermediate generating capacity and reactive nitrogen intermediate production. Lucigenin-dependent chemiluminescence stimulated with either FMLP or PMA declined during the first 2 days in culture and was negligible during the later days in culture. Superoxide radical production in response to either FMLP or PMA remained fairly constant for the first few days in vitro and then declined. NO2- concentration in monocyte-conditioned medium was fairly constant during the first few days in vitro but increased after 6 days. The return to tumoricidal competence after 3 to 4 days in culture was decreased by the addition of NG-monomethyl-L-arginine. These results indicate that reactive oxygen intermediates are employed by monocytes in the killing of tumor cells. However, after maturation of monocytes to macrophages, this mechanism becomes less important and reactive nitrogen intermediates are employed in mediating macrophage cytotoxicity.
Agonist-dependent phosphorylation of N-formylpeptide and activation peptide from the fifth component of C (C5a) chemoattractant receptors in differentiated HL60 cells.
Authors: Tardif M , Mery L , Brouchon L , Boulay F 
Published: December 2022

Abstract
Attenuation of signaling is a key step in controlling the cytotoxic potential of leukocyte responses to chemotactic factors. Antipeptide antibodies, directed against the N-formyl chemotactic peptide receptor (FPR) and the activation peptide from the fifth component of C (C5a) anaphylatoxin receptor (C5aR) of human neutrophils, were used to analyze the ability of these receptors to be phosphorylated. Our data show that, in granulocyte-like differentiated HL-60 cells, both FPR and C5aR undergo an agonist dose-dependent phosphorylation that reaches completion in less than 2 to 3 min, consistent with the rate and the dose-dependent attenuation of signaling in phagocytes. Therefore, phosphorylation might be one of the possible mechanisms involved in the desensitization process of FPR and C5aR. Addition of either C5a or the protein kinase C activator (PMA) did not appear to induce the phosphorylation of FPR in the absence of FMLP or to modulate the phosphorylation of the latter at low concentrations of agonist. In contrast, although FMLP at a saturating concentration barely stimulated the phosphorylation of unoccupied C5aR, it markedly potentiated C5aR phosphorylation in cells exposed to low concentrations of C5a. Moreover, PMA was able to induce C5aR phosphorylation in the absence of agonist, indicating that protein kinase C or protein kinase C-activated kinase(s) could be involved in the phosphorylation of C5aR. Pretreatment of cells with staurosporine, a potent but nonspecific inhibitor of protein kinase C, resulted in the partial inhibition of both FPR and C5aR phosphorylation induced by saturating concentrations of agonist, suggesting that a kinase different from protein kinase C might be mainly responsible for the phosphorylation of these chemotactic receptors.
Detection of HIV-specific cell-mediated cytotoxicity in the peripheral blood from infected children.
Authors: Buseyne F , Blanche S , Schmitt D , Griscelli C , Rivière Y 
Published: December 2022

Abstract
Cytotoxic T lymphocytes may play a significant role in containing the spread of HIV in infected individuals. Although HIV-infection is associated with immune suppression, a vigorous T lymphocyte response has been detected in infected adults. HIV can be transmitted from mother to child, either during pregnancy, when differentiation of the T lymphoid compartment is ongoing, or at birth when the neonate immune system is partially competent. The shorter asymptomatic period of pediatric infection could be related to differences in the host immune control of viral replication. HIV-specific cell-mediated cytotoxicity (CMC) from fresh and in vitro stimulated PBMC of HIV-infected children was measured. CD8+CD3+ T lymphocytes were found to be the major effector population. The vast majority of children examined had detectable HIV-specific CMC. A cross-sectional analysis of CMC responses as a function of clinical status revealed that 71% of asymptomatic children (CDC stage P1) recognized the Env protein, 14% the Gag protein, but none of them recognized the Pol protein. Cytolytic activities directed against these three proteins were detected in two thirds of paucisymptomatic children (P2A). In contrast, symptomatic children (P2B-F) did not show cytolytic activities toward the Gag and Pol proteins, and only 20% recognized the Env protein. In contrast in vitro generated secondary CTL were consistently detected at all stages of disease, even in children with low CD4+ cells counts.
Patterns of cytokine gene expression by CD4+ T cells from young and old mice.
Authors: Hobbs M V , Weigle W O , Noonan D J , Torbett B E , McEvilly R J , Koch R J , Cardenas G J , Ernst D N 
Published: December 2022

Abstract
We have analyzed the patterns of induced cytokine gene expression and cell cycle activity by CD4+ cells from mice, and have examined how these response patterns change during the aging process. CD4+ cells were isolated from spleens of young adult and old C57BL/6NNia mice and were stimulated in vitro with plate-bound anti-CD3 epsilon mAb. The cells were then assessed over time for the capacity to accumulate transcripts for IL-1 alpha, IL-1 beta, IL-2, IL-3, IL-4, IL-5, IL-6, IFN-gamma, TNF-alpha, and TNF-beta; to secrete IL-2, IL-3, IL-4, IL-5, IL-6, and IFN-gamma; and to progress through S phase. Before the first major cell division in culture (&lt; 32 h), stimulated CD4+ cells of the old group contained similar peak levels of IL-2, TNF-alpha, and TNF-beta transcripts relative to young adult controls, whereas IL-3, IL-4, IL-5, and IFN-gamma transcripts accumulated to significantly higher peak levels in the old group. These findings were consistent with the patterns of cytokine secretion later in culture (24 to 72 h): the peak IL-2 levels were similar between age groups, but the old group exhibited an enhanced capacity to release IL-3, IL-4, IL-5, and IFN-gamma. In contrast, CD4+ cells of the young group were superior in the hyper-expression of the housekeeping gene, rpL32, before cell division and in the levels of S phase activity throughout 3-day cultures. Similar analyses of CD4+ cells from mice of intermediate ages showed that the alterations in cytokine profiles occurred gradually from young adulthood to old age, whereas the reductions in proliferative capacity were late life changes. Consistent with previous reports, we found that the splenic CD4+ cell group also underwent a progressive, age-dependent increase in the proportions of cells expressing high levels of membrane CD44 (a phenotype associated with memory or effector cells). Moreover, the analysis of IL-3, IL-5, and IFN-gamma production by isolated CD4+CD44lo and CD4+CD44hi cells revealed that the capacity to produce these cytokines segregated predominantly with the CD44hi subset, regardless of donor age. Taken together, our data suggest that gradual age-associated shifts in the subset composition of the splenic CD4+ cell pool underlie progressive changes in the patterns of cytokine gene expression by this cell group.
Serum-IgE-facilitated allergen presentation in atopic disease.
Authors: van der Heijden F L , Joost van Neerven R J , van Katwijk M , Bos J D , Kapsenberg M L 
Published: December 2022

Abstract
The occurrence of facilitated Ag presentation (FAP) was investigated in atopic disease using an in vitro model in which the ability of CD23-expressing EBV-B cells was tested to present Der p II, a major allergen of housedust mite Dermatophagoides pteronyssinus, to cells of autologous Der p II-specific CD4+ T lymphocyte clones. Purified Der p II protein was immune complexed with Ig by preincubation in sera from atopic patients containing Der p II-specific IgE. Incubation of EBV-B cells with these complexes before using the cells as APC results in proliferation of the Der p II-specific T cells at a 1000-fold lower Der p II concentration than required for T cell activation by presentation of uncomplexed Der p II. FAP is not evident using sera from allergic and nonallergic control donors not containing Der p II-specific IgE. FAP is mediated by IgE and not by IgG, because it can be blocked completely by preincubating the serum from atopics with polyclonal anti-IgE and not with polyclonal anti-IgG. After pulsing EBV-B with precomplexed Der p II at 4 degrees C, FAP is as strong as after incubation at 37 degrees C, suggesting that FAP is the result of facilitated trapping of IgE-complexed allergen. CD23 was involved in facilitated trapping of the complexes, because FAP is blocked by preincubation of EBV-B with anti-CD23. In contrast to FAP of Der p II, which was mediated by all Der p II-specific sera tested, only one of four sera containing cat allergen-specific IgE was appropriate to mediate FAP to cat allergen-specific T cell clones. Inasmuch as FAP enables functional presentation of allergen in vivo at doses as low as several nanograms, FAP may contribute to the continuing of chronic allergic reactions in response to minute doses of aeroallergens, especially housedust mite allergens, in the environment.
Class II-restricted presentation of a hen egg lysozyme determinant derived from endogenous antigen sequestered in the cytoplasm or endoplasmic reticulum of the antigen presenting cells.
Authors: Brooks A G , McCluskey J 
Published: December 2022

Abstract
A cDNA encoding a form of hen egg lysozyme (HEL) lacking a leader sequence and predicted to be localized in the cytoplasm, was transfected into MHC class II-positive B lymphoma cells. Cytoplasmically expressed HEL (cytHEL) had a half-life of less than 5 min and did not react with HEL specific mAb suggesting non-native conformation. Cells expressing cytoplasmic HEL, as well as cells previously reported to express a low level of HEL retained in the endoplasmic reticulum (ERHEL), constitutively presented the HEL determinant encoded by residues 46-61 to a sensitive class II-restricted T hybridoma (3A9). Constitutive presentation of HEL determinants was not detectable in cytHEL or ERHEL transfectants using T hybridomas with lower sensitivity to exogenous Ag. Constitutive presentation of HEL46-61 derived from cytoplasmic HEL was demonstrable in multiple transfected clones and was most obvious when a CMV rather than SV40 promoter was used to express the cytHEL gene. The presentation of HEL46-61 by cytHEL transfectants was not due to HEL reuptake by bystander cells because there was no biochemical evidence of cytHEL shedding and cytHEL supernatants added to indicator APC did not result in HEL46-61 presentation. Constitutive presentation of endogenous HEL46-61 by the cytHEL and ERHEL transfectants was inhibited by chloroquine, and recovery of presentation of endogenous HEL was slower in cytHEL compared with ERHEL transfectants. The findings indicate that class II-restricted presentation of Ag retained in the cytoplasm or endoplasmic reticulum does take place but probably requires abundant levels of intracellular Ag and is easily disrupted by lysosomotropic agents. These pathways of presentation may be important when high levels of foreign endoplasmic reticulum-retained or cytoplasmic Ag are present (e.g., viral infection), and during the acquisition of self-tolerance by highly sensitive developing T cells.
Aberrant induction of T cell tolerance in B cell suppressed mice.
Authors: Gollob K J , Palmer E 
Published: December 2022

Abstract
Self-tolerance is the process by which the T cell repertoire develops without expressing self-reactive specificities. The mechanisms which functionally eliminate self-reactive T cells are clonal deletion and clonal inactivation, and both of these phenomena have been studied in T cell populations reactive to endogenous superantigens that are encoded by endogenous mouse mammary tumor proviruses (Mtv). The studies described here demonstrate that the kinetics of Etc-1 (encoded by the Mtv-9 open reading frame gene)-mediated deletion are much slower than that seen for Mls 1a (encoded by the Mtv-7 open reading frame), and that Etc-1-reactive T cells are present in the periphery up to 2 wk after birth. The deletion of peripheral Etc-1-reactive T cells late in ontogeny indicates an efficient mechanism of peripheral clonal deletion in these animals. The clonal deletion of Etc-1-reactive cells is abrogated in B cell-suppressed animals; however, clonal elimination of peripheral V beta 5+ or V beta 11+ (Etc-1 reactive) T cells can be induced when these mice are allowed to recover their B cell population after cessation of anti-mu treatment. Finally, we establish that peripheral Etc-1-reactive V beta 11+/CD4+ T cells remaining in B cell-suppressed and recovering animals are markedly less responsive to stimulation through the TCR than are control T cells. These data support the idea that peripheral self-reactive T cells can be rendered tolerant by two mechanisms which may be temporally related. This model suggests that clonal hyporesponsiveness may be followed by clonal deletion.