bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enhanced HIV-1 replication in retinoid-treated monocytes. Retinoid effects mediated through mechanisms related to cell differentiation and to a direct transcriptional action on viral gene expression.
Authors: Turpin J A , Vargo M , Meltzer M S 
Published: December 2022

Abstract
Vitamin A and other retinoids have profound effects on macrophage differentiation and function. Such effects could alter interactions between HIV and tissue macrophages, a principal target cell and reservoir for virus during HIV disease. Indeed, retinoids are used to treat various symptoms associated with HIV infection. We show that levels of virus replication in monocytes cultured 7 days before and continuously after HIV infection in 1 to 10 microM retinoic acid were 10- to 20-fold greater than those of control cells. No direct toxicity (detachment from substrate or cell death) was evident in infected or control monocytes treated with less than or equal to 10 microM retinoic acid. Maximum effects of retinoic acid (50% maximum effect was at 0.8 +/- 0.1 microM) required 5 to 7 days treatment before infection and persisted without additional treatment through more than 4 wk. RT activity in cultures of retinoic acid-treated monocytes reached maximum levels much earlier than those of control cultures, but the minimum tissue culture infectious doses for retinoic acid-treated and untreated monocytes were comparable. Retinoic acid treatment did not affect susceptibility of monocytes to HIV infection. Further, the frequency of infected cells in retinoic acid-treated and control cultures were also comparable: about 20% of cells in each culture expressed HIV proteins or RNA 2 wk after infection. In contrast, levels of HIV-specific RNA and DNA were 3- to 5-fold higher in the retinoic acid-treated over control monocytes 1 wk after infection. That retinoic acid increased levels of HIV gene expression in monocyte cultures without affecting the number of infected cells per culture suggested a transcriptional mechanism for the effect. This was confirmed in the U937 myeloid cell line transfected with HIV LTR linked to a chloramphenicol acetyl transferase reporter gene. Chloramphenicol acetyl transferase activity in lysates of retinoic acid-treated cells were 20-fold higher than that of control cells. These data show that retinoic acid significantly increased HIV replication in monocytes through mechanisms related to cell differentiation and to a direct transcriptional effect on viral gene expression.
Organization of the human T cell receptor zeta/eta gene and its genetic linkage to the Fc gamma RII-Fc gamma RIII gene cluster.
Authors: Jensen J P , Hou D , Ramsburg M , Taylor A , Dean M , Weissman A M 
Published: December 2022

Abstract
The zeta-subunit is the most recently characterized stoichiometric human TCR component. In this study we describe the molecular organization of the human zeta-gene. The zeta transcript is generated as the spliced product of eight exons that are separated by distances of 0.7 kb to more than 8 kb. Ribonuclease protection studies revealed multiple transcription initiation sites distributed over a range of approximately 115 bases. A variable number tandem repeat restriction fragment polymorphism contained within the structural gene has allowed for the localization of zeta within the human genome. Additionally, a restriction fragment polymorphism within the Fc gamma RII-Fc gamma RIII gene cluster has allowed for its localization on the map of human chromosome 1q and for the establishment of its linkage to the zeta-gene locus. A region that is highly homologous on a nucleotide level with the eta-exon of the murine zeta-gene is localized to the 3' region of the human zeta-gene. Surprisingly, translation of this region into protein results in a structure that is markedly divergent from its murine counterpart. This finding has important implications regarding the potential role of eta in T cell function.
CD28-stimulated IL-2 gene expression in Jurkat T cells occurs in part transcriptionally and is cyclosporine-A sensitive.
Authors: Williams T M , Moolten D M , Makni H , Kim H W , Kant J A , Kamoun M 
Published: December 2022

Abstract
CD28 is a glycoprotein expressed as a homodimer on the surface of a major subset of human T cells. Previous studies have shown that proliferation of peripheral blood T cells involving the CD28 pathway is associated with cyclosporine A (CsA) resistant IL-2 gene expression. This pathway was shown to specifically regulate the stability of mRNA for several lymphokines including IL-2. We have investigated the expression of the IL-2 gene in the Jurkat cell line, J32 clone, induced by CD28 stimulation. Cross-linked anti-CD28 mAb alone was sufficient to induce the release of small amounts of IL-2 (256 U/ml). The CD28-mediated IL-2 release was enhanced with simultaneous engagement of CD28 and CD2 or CD28 and CD3 molecules. Hybrid constructs in which the human IL-2 gene 5' flanking region drives luciferase expression (pIL-2-Luc) were used to help delineate whether the CD28 pathway activates the IL-2 gene transcriptionally. Costimulation of cells with CD28 mAb and either PHA or CD2 mAb induced a 20- to 90-fold increase in the expression of pIL-2-Luc as well as IL-2 release. Costimulation with CD28 mAb plus PMA gave only five- to sevenfold increase in enhancer activity. In contrast, no enhancer activity was detected after stimulation with CD28 or CD2 mAb alone. Both IL-2 release and pIL-2-Luc activity were inhibited by CsA in J32 cells. The degree of CsA inhibition was concentration dependent and was similar in cells stimulated with either CD28 mAb or CD3 mAb. Maximum inhibition was achieved with 1 microgram/ml of CsA. Studies with internal deletion mutations of the IL-2 gene 5' flanking sequence revealed that as with stimulation through the TCR pathway, the CD28 pathway requires 5' flanking sequences located within 500 bp of the transcription start site. These results are the first direct evidence that the triggering of CD28 molecule is sufficient to induce IL-2 release in J32 cells. Furthermore these studies strongly indicate that IL-2 gene expression induced by CD28 stimulation occurs, in part, transcriptionally and is CsA sensitive in these cells.
Induction of cytotoxic T lymphocytes specific for a syngeneic tumor expressing the E6 oncoprotein of human papillomavirus type 16.
Authors: Chen L , Mizuno M T , Singhal M C , Hu S L , Galloway D A , Hellström I , Hellström K E 
Published: December 2022

Abstract
Human papillomavirus (HPV) type 16 has been implicated in the etiology of cervical carcinomas, but it is unknown whether HPV-specific immunity can function in controlling the growth of HPV-associated carcinomas. We previously demonstrated that CD8+ T lymphocytes can inhibit the in vivo outgrowth of murine tumor cells transfected with the HPV-16 E7 gene and have now established a murine model to study the CTL responses to the E6 oncoprotein of HPV-16. Immunization of C3H/HeN mice with syngeneic fibroblasts expressing a transfected HPV-16 E6 gene induced regression of transplanted tumors expressing this gene. Populations of CTL isolated from the spleens of mice whose E6+ tumors had regressed were shown to specifically lyse E6+ target cells. The cytolytic activity was mediated by CD8+ CTL in a MHC restricted pattern. These data and our previous findings with transfected tumor cells expressing the E7 gene, support the conclusion that tumor cells associated with HPV-16 can be inhibited by CTL specific for molecules encoded by the HPV-16 E6 and E7 genes.
Cellular mechanisms of the antitumor activity of recombinant IL-6 in mice.
Authors: Mulé J J , Custer M C , Travis W D , Rosenberg S A 
Published: December 2022

Abstract
The systemic administration of human rIL-6 to mice resulted in the regression of established, 3-day pulmonary micrometastases from two weakly immunogenic tumors, but not from a nonimmunogenic tumor, in the absence of observable toxicity. Although IL-6 alone failed to have a significant therapeutic impact on advanced, 10-day pulmonary macrometastases from weakly immunogenic tumors, substantial cure rates of mice could be achieved when this cytokine was combined with cyclophosphamide. Histologic analysis of the lungs of mice receiving IL-6 revealed infiltration with lymphoid cells during the regression of pulmonary nodules from a weakly immunogenic tumor. IL-6-mediated tumor regression could be abrogated after selective in vivo depletion of either CD4 or CD8 T cell subsets by the systemic administration of specific mAb. In vivo generation of tumor-specific CTL, but not of lymphokine-activated killer cells, was detected in the lungs of IL-6-treated mice during regression of pulmonary metastases. Collectively, these findings demonstrate a role for IL-6 in the treatment of established solid tumors that have the capacity to elicit T cell responses in the host. Differences in host cellular mechanisms involved in tumor regression mediated by immunotherapy using IL-6 vs IL-2 are discussed.
Expression of an exogenous tumor necrosis factor (TNF) gene in TNF-sensitive cell lines confers resistance to TNF-mediated cell lysis.
Authors: Vanhaesebroeck B , Decoster E , Van Ostade X , Van Bladel S , Lenaerts A , Van Roy F , Fiers W 
Published: December 2022

Abstract
TNF, a cytokine with cytotoxic activity on a variety of tumor cells, is mainly produced by macrophages; however, some tumor cell types of non-macrophage origin, apparently resistant to TNF-mediated cell lysis, can also produce TNF. It is not clear whether these cells were TNF-resistant a priori or whether protective mechanisms against toxicity of autocrine TNF may be induced in TNF-producing cells. Murine L929sA fibrosarcoma cells, which are highly sensitive to TNF cytotoxicity, were transfected with the neomycin resistance (neor) gene, alone or in combination with the human (h) or the murine (m) TNF gene. All exogenous genes were under control of the constitutive SV40 early promoter. After cotransfection, the number of neor colonies was 10 to 100% as compared with the number of colonies upon transfection with the neor gene alone. An appreciable fraction of these colonies (50-100%) constitutively produced biologically active TNF. mTNF-producing L929 cells were fully TNF resistant, whereas hTNF-producing cells showed partial TNF resistance. Specific TNF binding could not be detected on mTNF-producing L929sA transfectants, whereas hTNF-producing cells showed reduced TNF binding. Apparently, TNF gene expression, even in a priori TNF-sensitive cells, can induce mechanisms to prevent toxicity by both autocrine and exogenous TNF. No TNF resistance was induced by expression of a gene sequence encoding the 9-kDa membrane-bound presequence part of the 26-kDa mTNF proform. Expression of a mutant 26-kDa TNF gene coding for a quasi-inactive mature mTNF induced only weak TNF resistance as compared with the complete resistance obtained after transfection with the wild-type gene. These findings show that the membrane-bound TNF presequence as such is not sufficient for induction of TNF resistance and imply that the active site of mature TNF is involved in modulation of TNF responsiveness upon autocrine TNF production.
Serologic, biologic and western blot analysis of human IgE-binding factor derived from a T cell hybridoma maintained in protein-free medium.
Authors: Steele J K , Domingo R , Gomi H , Ishizaka K 
Published: December 2022

Abstract
The human T cell hybridoma AC5 has been shown to produce an IgE-binding factor (IgEBF) upon stimulation with T cell mitogens, or anti-CD3 antibody. In this study, the line was established, propagated long term in a newly available serum-free, protein-free medium, and the factor it produced was analyzed. Serologic analysis, utilizing an ELISA assay and biotin-labeled human Ig of various isotypes, revealed that the IgEBF thus obtained was highly specific for the Ig epsilon-chain and was released primarily within the first 24 h after mitogen stimulation. Using biotin-labeled IgE as the detecting reagent, Western blot analysis of this factor demonstrated that the molecule was a single chain moiety of m.w. 64,000, and could be purified to apparent homogeneity by either DEAE or affinity (IgE column) chromatography. Detection of the IgEBF by ELISA and Western blot correlated well with activity in the previously employed rosette inhibition assay. Finally, purified IgEBF was found to suppress in vitro the production of IgE in the monoclonal human myeloma line U266, but not IgA or IgM-producing myelomas, providing evidence for the direct and specific regulatory action of this molecule on IgE-producing cells.
A genetically engineered human IgG mutant with enhanced cytolytic activity.
Authors: Shopes B 
Published: December 2022

Abstract
A mutant chimeric anti-5-dimethylaminonaphthalene-1-sulfonyl human Ig gamma that exhibited augmented effector function was constructed. Utilizing directed mutagenesis, a serine residue near the carboxyl terminus of the human IgG1 H chain (Ser444) was replaced by a cysteine. Novel intermolecular disulfide bonds between Cys444 residues linked pairs of Ig "tail-to-tail" to form covalent dimers ((H2L2)2). These dimers were 200-fold more efficient, compared with monomeric human IgG1, at antibody-dependent complement-mediated cytolysis of hapten-bearing erythrocytes. The ability to enhance the cytolytic activity of an mAb by genetic engineering may be of value in immunotherapy.
Termination of the B cell lymphoma dormant state in thymectomized AKR mice.
Authors: Haran-Ghera N , Peled A , Brightman B K , Fan H 
Published: December 2022

Abstract
AKR mice are highly susceptible to spontaneous T cell lymphomagenesis and thymus removal at the age of 1 to 3 mo greatly reduces its development. Twelve-mo-old AKR mice thymectomized at young age were shown previously to carry potential lymphoma cells that could be triggered to develop into B cell lymphomas (80 to 100%) after removal from their host "restrictive" environment into young histocompatible hosts. Additional attempts were made to terminate the potential lymphoma cell dormant state in 12-mo-old thymectomized AKR mice. Replenishment of some deficiencies caused by thymectomy at a young age, including a s.c. syngeneic thymus graft or a single injection of the dual tropic recombinant virus isolates DTV-71 or MCF-247 into 12-mo-old thymectomized AKR mice resulted in Ly-1+ pre-B or B cell lymphoma development in 80 to 98% of these treated mice. In vivo elimination of T cell subsets by administration of cyclosporin A or by mAb expressed on Th cells (anti-CD4) or cytotoxic T cells (anti-CD8) stimulated the progression of dormant potential lymphoma cells towards B cell lymphoma development. The most striking results were observed after administration of anti-CD8 mAb: 90 to 100% of these treated mice developed Ly-1+ B cell lymphomas within 80 days. The effect of rIL-2 on dormant PLC was also tested. Administration of rIL-2 to 12-mo-old thymectomized mice terminated tumor dormancy in 94% of the treated mice within 66 days. Tests of the resulting B lymphomas for dual tropic recombinant virus/mink cell focus-inducing virus infection indicated that the breakdown of tumor dormancy did not result from development of pathogenic class I mink cell focus-inducing viruses. These results suggest that T cell subsets and/or their products are involved in the proliferation arrest of potential lymphoma cells present in thymectomized AKR mice.
Donor-type activated natural killer cells promote marrow engraftment and B cell development during allogeneic bone marrow transplantation.
Authors: Murphy W J , Bennett M , Kumar V , Longo D L 
Published: December 2022

Abstract
Purified NK cells were obtained from mice with severe combined immune deficiency and were activated with human IL-2 (hrIL-2) in vitro to determine if, once activated, these cells could be transferred with compatible bone marrow cells (BMC) and promote marrow engraftment in irradiated allogeneic recipients. After culture with hrIL-2, these cells maintained a phenotypic and lytic spectrum consistent with a pure population of activated NK cells. These activated NK cells were then adoptively transferred with the donor BMC and rhIL-2 into lethally irradiated allogeneic hosts. The addition of NK cells with the BMC allowed for more rapid hematopoietic engraftment as determined through short term studies, and greater donor-derived chimerism with accelerated reconstitution of the B cell population as determined with long term analysis. No evidence of graft-vs-host disease was detected in the recipients receiving the activated NK cells with allogeneic T cell replete BMC and hrIL-2. The mechanism by which the transferred NK cells improved BMC engraftment was at least partly through the abrogation of the host effector cell's ability to mediate resistance to the marrow graft. Thus, the administration of donor-type activated NK cells with BMC and hrIL-2 may significantly augment hematopoietic engraftment and immune reconstitution in the clinical setting of allogeneic BMT without giving rise to graft-vs-host disease.
Comparative stabilities in vitro and in vivo of a recombinant mouse antibody FvCys fragment and a bisFvCys conjugate.
Authors: Cumber A J , Ward E S , Winter G , Parnell G D , Wawrzynczak E J 
Published: December 2022

Abstract
A murine antibody FvCys fragment with a single additional cysteine residue at the C terminus of the VH domain was expressed in Escherichia coli from a modified expression plasmid containing the structural genes for the VH and VL domains derived from the anti-lysozyme hybridoma D1.3. Chemical cross-linking between the introduced sulfhydryl groups of two FvCys fragments by means of bis-maleimidohexane was used to generate a bisFvCys conjugate. The stability of the bisFvCys conjugate and an FvCys analogue that had been reacted with N-ethyl-maleimide to block the free sulfhydryl group, FvCys(BL), were compared after 125I-labeling. The bisFvCys conjugate was completely stable to incubation in solution at 37 degrees C for 24 h whereas only 60% of the FvCys(BL) fragment remained soluble. After i.v. administration to normal Wistar rats, both Fv proteins were rapidly cleared from the circulation with biphasic kinetics that were best fitted to a two-compartment open pharmacokinetic model. The alpha-phase half-life of the bisFvCys conjugate, 0.32 h, was significantly longer than that of the FvCys(BL) fragment, 0.15 h (p less than 0.001) whereas there was no significant difference between the beta-phase half-lives, 1.4 to 1.6h. No chain cleavage or covalent attachment to serum protein was detected by SDS-PAGE analysis of serum samples. However, gel permeation HPLC revealed that both Fv proteins associated with serum proteins in vivo and in vitro.
Diversity of T cell receptor-alpha chain transcripts from hyperimmune alloreactive T cells.
Authors: Tjoa B , Kranz D M 
Published: December 2022

Abstract
Alloreactive T cells represent a relatively large fraction of the T cell population compared with the fraction of T cells that are specific for other foreign Ag. Recent findings indicate that most alloreactive T cells recognize endogenous peptides in association with a non-self MHC product. In light of these observations, it is perhaps not surprising that previous studies of the size of the TCR-alpha beta repertoire among alloreactive cells showed that they express many different V alpha and V beta genes. To further access the extent of diversity among alloreactive cells, we examined V alpha J alpha combinatorial diversity in polyclonal populations of a BALB/c anti-BALB.B mixed lymphocyte response. A long term culture from naive mice contained a diverse repertoire of V alpha J alpha combinations that was similar to the diversity present among unstimulated splenic T cells. In contrast, long term cultures from hyperimmunized animals contained "dominant" clones of T cells that expressed a restricted repertoire of V alpha J alpha combinations. Examination of the nucleotide sequences of these alpha-chains suggested that there was selective expansion of T cells with identical alpha-chains. In addition, T cells that express the same V alpha J alpha combination but different junctions were also identified. Consistent with previous results, the isolates from hyperimmune animals did not contain somatic mutations in the CDR3 region of the alpha-chains. Nevertheless, the results suggest that T cells may be subject to in vivo selection and clonal expansion analogous to the process of affinity maturation of Ig.
Migration of recombinant IL-2-activated T and natural killer cells in the intercellular space of human H-2 glioma spheroids in vitro. A study on adhesion molecules involved.
Authors: Jääskeläinen J , Mäenpää A , Patarroyo M , Gahmberg C G , Somersalo K , Tarkkanen J , Kallio M , Timonen T 
Published: December 2022

Abstract
The migration of rIL-2-activated T and NK cells into the intercellular space of glioma tissue was studied using multicellular spheroids grown from the human H-2 glioblastoma cell line as targets. Lymphocytes of all analyzed subtypes migrated into the spheroids, but CD56+ cells were particularly migratory. Lymphocytes and the H-2 tissue expressed adhesion molecule subunits for the following potential cell-cell or cell-matrix interactions: alpha 3 beta 1 (VLA-3) to fibronectin, laminin, and collagen; alpha 4 beta 1 (VLA-4) and alpha 5 beta 1 (VLA-5) to fibronectin; alpha 6 beta 1 (VLA-6) to laminin; alpha 4 beta 1 to VCAM-1; alpha L beta 2 (Leu-CAMa/LFA-1) to CD54 (ICAM-1); CD44 to fibronectin, collagen, laminin, hyaluronate; CD2 to CD58 (LFA-3); and CD56 (N-CAM) to CD56. In the H-2 tissue, CD54 and VCAM-1 were expressed as a gradient. The expression of CD54 was weak in the peripheral zone and the expression was stronger in the quiescent deeper zone, whereas the distribution of VCAM-1 showed an inversed pattern. The low expression of CD54 was up-regulated along the frontier of migrating lymphocytes. The migration was almost totally prevented by the anti-CD18 (beta 2) mAb IB4 and TS1/18, and also strongly inhibited by the anti-CD54 mAb LB-2. Instead, mAb known to inhibit the binding of beta 1 integrins to fibronectin were not significantly inhibitory. However, a combination of the GPEILDVPST and GRGDS peptides, which compete for the binding of alpha 4 beta 1 and alpha 5 beta 1 to fibronectin and may also affect other adhesion systems, partially prevented migration.