bluuebunny/crossref_metadata_2025_split huggingface dataset:
T cell stimulation via CD47: agonistic and antagonistic effects of CD47 monoclonal antibody 1/1A4.
Authors: Waclavicek M , Majdic O , Stulnig T , Berger M , Baumruker T , Knapp W , Pickl W F 
Published: December 2022

Abstract
CD47/integrin-associated protein has been extensively studied on various cell types. The function of CD47 on T cells, however, remained poorly understood. We demonstrate here that our CD47 mAb 1/1A4 has both inhibitory as well as costimulatory effects in terms of T cell activation. Soluble, not cross-linked, CD47 mAb 1/1A4 blocks allogeneic MLRs. This effect is predominantly observed with suboptimal numbers of stimulator cells. In contrast, cross-linking of CD47 in the presence of CD28 mAb or phorbol ester induces vigorous T cell proliferation that is sensitive to cyclosporin A. Cross-linking, but not immobilization, of the CD47 mAb 1/1A4 is an essential requirement for the CD28- or phorbol ester-dependent induction of T cell mitogenesis. Furthermore, CD47 mAb 1/1A4 induces T cell proliferation when coimmobilized with a CD3 mAb to the same surface. Ligation with cross-linked 1/1A4 mAb induces an increase in intracellular free calcium levels and leads to tyrosine phosphorylation of various cellular proteins and, in the presence of suboptimal concentrations of plate-bound CD3 mAb, to enhanced IL-2 promotor activity in T cells. Furthermore, we present evidence that upon cross-linking of CD47 with mAb 1/1A4, purified T cells acquire responsiveness for several T cell growth factors. IL-1beta and/or IL-6 dramatically augment this CD47-induced cytokine responsiveness. Our results suggest that the novel activation pathway via CD47 might be critically involved in Ag-dependent and Ag-independent T cell functions.
Adoptive transfer of in vitro-targeted, activated T lymphocytes results in total tumor regression.
Authors: Altenschmidt U , Klundt E , Groner B 
Published: December 2022

Abstract
Adoptive immunotherapy of cancer uses the transfer of tumor-reactive immune cells. The success of this procedure is dependent upon the specificity of the transferred immune cells, their number, and their ability to reach their target cells. We genetically modified T lymphocytes and equipped them with the ability to specifically recognize tumor cells. Tumor cells overexpressing the ErbB-2 receptor served as a model. The target cell recognition specificity is conferred to T lymphocytes by transduction of a chimeric gene encoding the zeta-chain of the TCR and a single chain antibody (scFv(FRP5)) directed against the human ErbB-2 receptor. The chimeric scFv(FRP5)-zeta gene was introduced into primary mouse T lymphocytes via retroviral gene transfer. Naive T lymphocytes were activated and infected by cocultivation with a retrovirus-producing packaging cell line. The scFv(FRP5)-zeta fusion gene was expressed in &gt;75% of the T cells. These T cells lysed ErbB-2-expressing target cells in vitro with high specificity. We tested the antitumor efficacy of scFv(FRP5)-zeta-expressing T cells in a syngeneic BALB/c model. The mice were treated with autologous, transduced T cells. The adoptively transferred scFv(FRP5)-zeta-expressing T cells caused total regression of ErbB-2-expressing tumors. The presence of the transduced T lymphocytes in the tumor tissue was monitored. No humoral response directed against the transduced T cells was observed. Abs directed against the ErbB-2 receptor were detected upon tumor lysis.
TCR vaccines for active immunotherapy of T cell malignancies.
Authors: Okada C Y , Wong C P , Denney D W , Levy R 
Published: December 2022

Abstract
We have developed a TCR-based vaccine approach for the treatment of T cell malignancies. TCR genes were isolated from C6VL, a T cell tumor of C57BL/Ka origin. The transmembrane encoding domains of the TCR genes were replaced by sequences encoding for phosphatidylinositol-linked cell surface expression. A high expressing cell line was produced by transfection and amplification of the TCR genes. Large quantities of soluble native C6VL TCR-alphabeta protein was obtained by treating the high-expressing cells with a specific phospholipase and purifying the released TCR by affinity chromatography. Following vaccination with the TCR linked to keyhole limpet hemocyanin, specific anti-TCR humoral responses were induced. Both the carrier protein and an adjuvant were required for optimal responses. Hyperimmune serum from vaccinated mice reacted specifically with C6VL cells, and the immunizations did not affect the TCR repertoire, which suggested that the immune response was Id specific. The TCR-vaccinated mice were specifically protected from a lethal number of C6VL tumor cells. B cell-deficient mice were not protected by TCR vaccinations. Similarly, TCR-immunized mice depleted of CD8+ cells prior to tumor challenge were not protected. Thus, C6VL TCR vaccine effectively stimulated tumor protection, which depends on the presence of both B cells and CD8+ T cells.
Beta2 integrins are not required for tyrosine phosphorylation of paxillin in human neutrophils.
Authors: Fernandez R , Boxer L A , Suchard S J 
Published: December 2022

Abstract
Although many of the receptors mediating neutrophil (polymorphonuclear leukocyte (PMN)) adhesion to extracellular matrix (ECM) proteins have been identified, the signal transduction pathways leading to cell spreading are not clearly defined. Studies showing that protein tyrosine phosphorylation increases with PMN adhesion suggest that phosphorylation is critical for adhesion-dependent processes. In other cells, increased tyrosine phosphorylation of focal adhesion kinase (FAK) and paxillin are thought to play pivotal roles in ECM-mediated signaling. In the present study we compared the tyrosine phosphorylation of FAK and paxillin in PMNs plated onto thrombospondin (TSP) or laminin (LN). Increased tyrosine phosphorylation of paxillin correlated with adhesion and spreading of PMNs plated onto LN or TSP. In PMNs adherent to LN, the kinetics of FAK phosphorylation preceded the kinetics of paxillin phosphorylation, suggesting that paxillin may be a downstream target of FAK. In contrast, FAK was not phosphorylated in PMNs spread on TSP. These findings suggested activation of different signaling pathways in TSP- vs LN-adherent PMNs. Others have proposed that paxillin phosphorylation requires beta2 integrins. Therefore, we used PMNs from a patient with leukocyte adhesion deficiency (LAD), lacking beta2 integrins, to determine whether these receptors were necessary for paxillin phosphorylation. LAD PMNs did not adhere to LN, and consequently, there was no tyrosine phosphorylation of FAK or paxillin. In contrast, paxillin, but not FAK, was phosphorylated in LAD PMNs adherent and spread on TSP. These results indicate that ECM-beta2 integrin-mediated signaling initiates the FAK/paxillin signaling pathway(s), while TSP-mediated signaling results in paxillin phosphorylation independent of FAK phosphorylation.
Characterization of the CCR2 chemokine receptor: functional CCR2 receptor expression in B cells.
Authors: Frade J M , Mellado M , del Real G , Gutierrez-Ramos J C , Lind P , Martinez-A C 
Published: December 2022

Abstract
We have derived anti-human CCR2-specific mAbs by immunization with synthetic peptides corresponding to CCR2 sequences presumably involved in the interaction with its ligand(s). The characterization of these mAbs includes the ability to recognize the CCR2 receptor specifically, as well as the function based on their ability to promote Ca2+ influx or to block MCP-1-induced Ca2+ influx and chemotaxis. One mAb (MCP-1 R02) that is directed to the NH2 terminal domain of the CCR2 receptor has MCP-1 agonist activity, and two that recognize the third extracellular domain (MCP-1R04 and MCP-1 R05) have MCP-1 antagonist activity. We analyzed the presence of CCR2 in several PBL and tonsil-derived leukocyte populations and found expression of this receptor in monocytes, activated T cells, and, surprisingly, in B cells. CCR2 receptor expression in B cells was further corroborated in Southern blot using CCR2-specific probes. Moreover, both MCP-1 and the agonist mAb trigger specific B cell migration via a PTX-sensitive mechanism, indicating the presence of a functional CCR2 receptor in these cells.
Generation of HER-2/neu-specific cytotoxic neutrophils in vivo: efficient arming of neutrophils by combined administration of granulocyte colony-stimulating factor and Fcgamma receptor I bispecific antibodies.
Authors: Heijnen I A , Rijks L J , Schiel A , Stockmeyer B , van Ojik H H , Dechant M , Valerius T , Keler T , Tutt A L , Glennie M J , van Royen E A , Capel P J , van de Winkel J G 
Published: December 2022

Abstract
Abs are able to induce inflammatory antitumor responses by recruiting IgG Fc receptor (FcgammaR)-bearing cytotoxic effector cells. We recently described the capacity of the high affinity FcgammaRI (CD64) to trigger cytotoxic activity of neutrophils (PMN) during granulocyte CSF (G-CSF) treatment. To take advantage of FcgammaRI as a cytotoxic trigger molecule on PMN, two Ab constructs were prepared. We show that a chimeric human IgG1 Ab (Ch520C9) and an anti-FcgammaRI bispecific Ab (BsAb; 22x520C9), both directed to the proto-oncogene product HER-2/neu, interact with FcgammaRI. In addition, both Ab constructs mediate enhanced lysis of HER-2/neu-expressing tumor cells by G-CSF-primed PMN. However, engagement of FcgammaRI by Ch520C9 was inhibited by human serum IgG, thereby abrogating the enhanced Ch520C9-mediated cytotoxicity. BsAb 22x520C9, which binds FcgammaRI outside the ligand binding domain, effectively recruits the cytotoxic potential of FcgammaRI on G-CSF-primed PMN regardless of the presence of human serum. These results indicate that under physiologic conditions, serum IgG impairs activation of FcgammaRI-mediated cytotoxicity by conventional antitumor Abs. The IgG blockade can be circumvented with anti-FcgammaRI BsAbs. Using human FcgammaRI transgenic mice we demonstrate that BsAb 22x520C9 is able to engage FcgammaRI in vivo. BsAb 22x520C9 injected i.v. was readily detected on circulating PMN of G-CSF-treated transgenic animals. In addition, we showed that PMN remain "armed" with BsAb 22x520C9 during migration to inflammatory sites, and that after isolation such PMN specifically lyse HER-2/neu-expressing tumor cells. These results point to the possibility of targeting anti-FcgammaRI BsAbs to G-CSF-primed PMN in vivo, endowing them with specific anti-tumor activity.
IL-11 regulates macrophage effector function through the inhibition of nuclear factor-kappaB.
Authors: Trepicchio W L , Wang L , Bozza M , Dorner A J 
Published: December 2022

Abstract
Recombinant human IL-11 (rhIL-11) is an anti-inflammatory cytokine that can reduce the production of inflammatory mediators such as TNF-alpha, IL-1beta, IL-12, IL-6, and nitric oxide. Inhibition of proinflammatory cytokine production from activated macrophages was associated with a reduction in the levels of LPS-induced TNF-alpha, IL-1beta, IL-6, and IL-12 p40 mRNA. Analysis of rhIL-11 effects on transcription factors that activate proinflammatory cytokines demonstrated that the level of LPS-induced NF-kappaB binding activity in the nucleus of rhIL-11-treated peritoneal macrophages was significantly reduced. The block to NF-kappaB nuclear translocation correlated with the ability of rhIL-11 to maintain or increase protein levels of the inhibitors of NF-kappaB, IkappaB-alpha, and IkappaB-beta following LPS treatment. Furthermore, rhIL-11-treatment of LPS macrophages resulted in significant elevation of IkappaB-alpha and IkappaB-beta mRNA levels. These results suggest that the anti-inflammatory activity of rhIL-11 is mediated in part by inhibition of NF-kappaB-dependent transcriptional activation. Furthermore, these studies demonstrate for the first time the regulation of IkappaB-beta by an anti-inflammatory cytokine. Given the finding that inappropriate activation of NF-kappaB contributes to multiple inflammatory conditions, the ability of rhIL-11 to inhibit the binding activity of this pleiotropic transcription factor indicates that rhIL-11 has therapeutic potential in a wide range of diseases.
Identification of a new mouse beta-chemokine, thymus-derived chemotactic agent 4, with activity on T lymphocytes and mesangial cells.
Authors: Tanabe S , Lu Z , Luo Y , Quackenbush E J , Berman M A , Collins-Racie L A , Mi S , Reilly C , Lo D , Jacobs K A , Dorf M E 
Published: December 2022

Abstract
Thymus-derived chemotactic agent 4 (TCA4), a new member of the beta-chemokine family, was cloned from a mouse thymic cDNA library. High levels of TCA4 mRNA are expressed in thymus; lower levels of message are found in spleen, heart, and kidney. Anti-TCA4 antibodies were used to localize sites of TCA4 expression within lymphoid tissues. In the thymus, UEA-1+ medullary epithelial cells, some endothelial cells, and additional undefined stromal elements were stained with anti-TCA4. TCA4 was also expressed as a meshlike network in splenic white pulp and in the medullary region of the lymph nodes. In addition, some lymph node and splenic blood vessels stained with anti-TCA4 antibodies. Rel B NFkappaB-deficient mice lack a transcription factor required for the generation of dendritic cells and the development of an organized thymic medulla. Rel B-deficient animals express very low levels of TCA4 in the thymus and little or no TCA4 in the periphery. At subnanomolar concentrations, TCA4 is a chemoattractant of mature T cells; the potential role of this novel chemokine in facilitating normal lymphocyte traffic is discussed. TCA4 is also a chemoattractant of cultured mesangial cells. Neutralizing anti-TCA4 mAb was used to demonstrate the specificity of TCA4-mediated cell migration. Finally, competitive binding studies with a SV40-transformed mouse mesangial cell line demonstrated that other murine beta-chemokines (monocyte chemotactic protein-1, macrophage inflammatory protein-1alpha, macrophage inflammatory protein-1beta, and thymus-derived chemotactic agent 3) do not compete for TCA4 binding.
Priming with IL-4 and IL-13 during HIV-1 infection restores in vitro IL-12 production by mononuclear cells of HIV-infected patients.
Authors: Marshall J D , Robertson S E , Trinchieri G , Chehimi J 
Published: December 2022

Abstract
The production of proinflammatory cytokines can be regulated by several factors that exert activating or inhibitory effects. IL-4, IL-10, IL-13, TGF-beta, and PGE2 have demonstrated a very wide range of potent macrophage-deactivating activities and, specifically, down-regulation of the production of many proinflammatory monokines. IL-12 plays a key role during immune response by providing a link between natural resistance and adaptive immunity. We and others have previously shown an impairment in IL-12 production by PBMC from HIV-1-infected individuals in response to various stimuli, but defining the mechanism responsible remains elusive. In this study, we observed that pretreatment of PBMC from patients with IL-4 or IL-13 for 24 h primes the cells for enhanced production of IL-12 in response to Staphylococcus aureus, and almost completely restores their deficient IL-12 production when compared with healthy controls. Although this priming effect was completely abrogated by IL-10 and PGE2, IL-10 was produced equivalently by untreated and IL-4- or IL-13-pretreated PBMC from both patients and controls. Additionally, indomethacin, which shuts off PGE2 synthesis, and cAMP-blocking reagents failed to restore or enhance IL-12 production. The priming effect of IL-4 and IL-13 is at the transcription level for both p40 and p35 genes. This complete restoration of IL-12 production by Th2-associated cytokines was unexpected in light of the mutually antagonistic roles of IL-12 and IL-4 in promoting Th1 or Th2 immune responses.
Telomerase is up-regulated in human germinal center B cells in vivo and can be re-expressed in memory B cells activated in vitro.
Authors: Hu B T , Lee S C , Marin E , Ryan D H , Insel R A 
Published: December 2022

Abstract
The extensive proliferation that B lymphocytes undergo in germinal centers could compromise generation of long term B cell memory if there occurs shortening of the telomeres of germinal center B cells with cell division. Telomere length, which is thought to act as a "mitotic clock" for somatic cells that dictates cellular senescence, can be preserved by the enzyme telomerase. Human tonsil germinal center B cells consistently expressed 100- to 1000-fold higher levels of telomerase activity than naive or memory B cells, which had no or very low detectable activity, as analyzed by the telomere repeat amplification protocol assay. In vitro stimulation of human memory B cells through surface Ig or CD40 was capable of up-regulating telomerase. The findings suggest that longevity of B cell memory is maintained, despite multiple cell divisions in the generation of a memory B cell, by up-regulation of telomerase in germinal center and activated memory B cells.
Correction of defective expression in MHC class II deficiency (bare lymphocyte syndrome) cells by retroviral transduction of CIITA.
Authors: Bradley M B , Fernandez J M , Ungers G , Diaz-Barrientos T , Steimle V , Mach B , O'Reilly R , Lee J S 
Published: December 2022

Abstract
Retrovirus-mediated gene transfer was used to restore expression to MHC class II-negative patient cells from complementation group A(II) of MHC class II immunodeficiency or bare lymphocyte syndrome (BLS). The cells of these patients do not transcribe MHC class II genes due to a defect in the trans-acting factor, CIITA. We constructed a vector, pGAG/Ii-CIITA, with the MHC class II-associated invariant chain promoter driving CIITA expression. Cocultivation with the virus producer line was consistently shown to be the optimal method for infection of all cell types. The induction of MHC class II expression after virus infection was rapid, and high levels of expression were achieved in cell lines within 1 wk of infection. In addition, expression was easily detectable even in peripheral blood cells of a BLS patient within a few days. Cell lines maintained in vitro for several months remained positive, and the proportion of cells with surface expression of DR was correlated with the number of integrated proviruses. Moreover, transduced B lymphoblastoid cell lines readily established tumors in CB17-scid/scid mice, and the MHC class II-positive cells demonstrated a clear competitive advantage in vivo. Ultimately, we hope to use this transduction system to restore normal immune function to a BLS patient for which no other therapeutic option currently exists.
Distinct methylation states of the CD8 beta gene in peripheral T cells and intraepithelial lymphocytes.
Authors: Hamerman J A , Page S T , Pullen A M 
Published: December 2022

Abstract
The CD8 coreceptor is expressed on both immature and mature T cells as either an alphabeta heterodimer or an alpha alpha homodimer. Thymocytes and peripheral T cells express CD8 alphabeta, whereas TCR alphabeta+ intraepithelial lymphocytes (IEL) express CD8 alpha alpha or CD8 alphabeta, and the majority of TCR gammadelta+ IEL bear CD8 alpha alpha. The presence of CD8 beta enhances the signaling and adhesion properties of the CD8 alphabeta coreceptor and is necessary for efficient T cell development in the thymus, but is not required for the extrathymic maturation of CD8 alpha alpha+ IEL. To address whether CD8 alpha alpha+ IEL express CD8 beta during their development, we examined the methylation state of cytosines in the CD8 beta gene 5' regulatory region to identify those for which the methylation state inversely correlates with expression of the CD8 beta protein. We identified four such cytosines that were demethylated in CD8 beta-expressing thymocytes and T cells. Interestingly, these cytosines were also demethylated in CD4+ lymph node T cells that had transiently expressed CD8 beta during their development. The methylation state of these cytosines was examined in DNA purified from TCR alphabeta+ CD8 alpha alpha+ and TCR alphabeta+ CD8 alphabeta+ IEL, as well as from TCR gammadelta+ CD8 alpha alpha+ and CD3- CD8 alpha alpha+ IEL. The methylation pattern for TCR alphabeta+ CD8 alpha alpha+ IEL DNA was distinct from that seen for DNA from CD4+ lymph node cells, suggesting that TCR alphabeta+ CD8 alpha alpha+ IEL have not previously expressed CD8 beta. Analysis of DNA from CD3- CD8 alpha alpha+ IEL indicated that the unique methylation pattern of the CD8 beta gene in TCR alphabeta+ CD8 alpha alpha+ IEL DNA was not due to transcription of the CD8 alpha gene or the influence of the gut microenvironment.
Identification of a STAT6 domain required for IL-4-induced activation of transcription.
Authors: Lu B , Reichel M , Fisher D A , Smith J F , Rothman P 
Published: December 2022

Abstract
Tyrosine phosphorylation of STAT6 in response to IL-4 results in the formation of STAT6 homodimers that bind specific DNA elements. Although binding sites for STAT6 have been shown to be important for the function of several IL-4-inducible promoters, the role of STAT6 in this activation has not been defined. To determine whether STAT6 is a transcriptional activator, different portions of the carboxyl terminus of STAT6 were fused to the yeast Gal4 protein DNA binding domain. Analysis of these chimeric Gal4-STAT6 proteins demonstrates that a 140-amino-acid proline-rich region of the carboxyl terminus of STAT6 contains a region that activates transcription. Truncation mutants of STAT6 that lack this domain cannot activate transcription and are capable of repressing transcription stimulated by a wild-type STAT6 protein. Strikingly, the ability of IL-4 to induce transcription from the Ig germline epsilon promoter is suppressed by overexpression of a carboxyl-terminal deletion mutant of STAT6. These studies demonstrate that the carboxyl terminus of STAT6 contains an activating domain required for the induction of genes by IL-4.
Effect of mitogenic stimulation and DNA methylation on human T cell DNA methyltransferase expression and activity.
Authors: Yang J , Deng C , Hemati N , Hanash S M , Richardson B C 
Published: December 2022

Abstract
DNA methylation, a mechanism modifying gene expression, is mediated in part by the enzyme DNA methyltransferase. Reduced levels of T cell DNA methyltransferase have been observed in lupus-like diseases, and increased levels have been reported in malignancies. Little is known concerning the regulation of human DNA methyltransferase. In this report we demonstrate that mitogenic T cell stimulation causes an increase in DNA methyltransferase mRNA and enzyme activity. We also show that pharmacologic inhibition of T cell DNA methylation causes an increase in the rate of DNA methyltransferase mRNA transcription and a corresponding increase in mRNA levels and enzyme activity. This suggests that DNA methyltransferase is itself regulated in part by DNA methylation status, possibly representing a feedback mechanism. DNA methylation inhibition also resulted in an increase in Ha-ras and c-jun mRNA levels, overexpression of which increases DNA methyltransferase in murine systems. These results thus identify two mechanisms regulating levels of human T cell DNA methyltransferase and raise the possibility that abnormalities in either could contribute to disorders associated with altered DNA methylation.