bluuebunny/crossref_metadata_2025_split huggingface dataset:
The autocrine production of transforming growth factor-beta 1 during lymphocyte activation. A study with a monoclonal antibody-based ELISA.
Authors: Lucas C , Bald L N , Fendly B M , Mora-Worms M , Figari I S , Patzer E J , Palladino M A 
Published: December 2022

Abstract
We describe the production and characterization of three mAb to transforming growth factor-beta (TGF-beta) and the use of two of them for the development of a TGF-beta 1-specific ELISA and for the study of the regulation of immune function in vitro. All three mAb bound recombinant human TGF-beta 1 (rHuTGF-beta 1) with high affinity and recognized the dimer form of this molecule in immunoblots. mAb 2G7 immunoprecipitated rHuTGF-beta 1, TGF-beta 2, and rHuTGF-beta 3 and neutralized the growth inhibitory activity of all three molecules in vitro on mink lung epithelial-like cells, Mv1Lu, indicating a shared neutralization epitope. mAb 4A11 neutralized and immunoprecipitated only rHuTGF-beta 1, and mAb 12H5 immunoprecipitated rHuTGF-beta 1 but had no effect on the bioactivity of either rHuTGF-beta 1, TGF-beta 2, or rHuTGF-beta 3. These results suggest that a second neutralization epitope may be unique to TGF-beta 1. The ELISA was developed with mAb 4A11 and 12H5, with a range of 0.63 to 40 ng/ml, i.e., a sensitivity of 0.63 ng/ml or 63 pg/sample. The assay is accurate, precise, and specific for the active but not the inactive or latent TGF-beta 1 complex and fails to react with TGF-beta 2, rHuTGF-beta 3, inhibin A, and activin A. Supernatants obtained from serum-free cultures of human PBMC from multiple donors contained significant quantities of TGF-beta 1 (3 to 15 ng/ml), which was detected in the ELISA only after pH 2 treatment to convert latent TGF-beta to the active form. Treatment of the PBMC with either recombinant human IL-2 (rHuIL-2) or PHA-P/PMA enhanced the production of latent TGF-beta 1. mAb 4A11 and 2G7, but not mAb 12H5 enhanced both the proliferative response of PBMC to rHuIL-2/rHuTNF-alpha and PHA-P and the development of the rHuIL-2/rHuTNF-alpha treated PBMC into LAK cells with cytotoxic activity against COLO target cells. These findings suggest that although PBMC secrete latent TGF-beta 1, mechanisms that convert the latent TGF-beta complex into an active form exist in vitro and that the endogenously produced TGF-beta can regulate immune functions in an autocrine fashion.
Evaluation of the antibody-dependent cytotoxic capabilities of individual human monocytes. Role of Fc gamma RI and Fc gamma RII and the effects of cytokines at the single cell level.
Authors: Connor R I , Shen L , Fanger M W 
Published: December 2022

Abstract
In this report we present evidence that not all human peripheral blood monocytes mediate antibody-dependent cellular cytotoxicity (ADCC), and that this function may be determined on an individual cell by both the type and level of expression of FcR, and by the state of cellular activation and/or differentiation. Although the diverse range of effector and regulatory functions performed by human monocytes suggests the possibility of distinct subsets, it is not clear whether observed functional heterogeneity reflects the presence of true monocyte subpopulations, or whether this diversity represents a continuum of maturational states present in the peripheral circulation. In an attempt to address this question, we investigated the ability of human monocytes to carry out ADCC at the single cell level, with emphasis on the role of the three FcR for IgG (Fc gamma RI, Fc gamma RII, and Fc gamma RIII) in mediating cytotoxicity. Using a modified plaque assay, 58.3% +/- 4.9 of freshly isolated monocytes mediated ADCC, as evidenced by the formation of lytic plaques in monolayers of ox erythrocyte (oxE) target cells. Significant increases in the number of plaque-forming cells were observed after positive selection by flow microfluorimetry for those monocytes expressing high levels of Fc gamma RI and Rc gamma RII, but not Fc gamma RIII. Bispecific antibodies composed of Fab fragments of anti-oxE antibody covalently coupled to Fab fragments of anti-Fc gamma R antibodies were used to independently evaluate the ability of Fc gamma RI, Fc gamma RII, and Fc gamma RIII to mediate single cell cytotoxicity. Significant increases in the number of plaque-forming cells were observed in the presence of anti-Fc gamma RI x anti-oxE and anti-Fc gamma RII x anti-oxE bispecific antibodies, confirming the efficiency of Fc gamma RI and Fc gamma RII as cytotoxic trigger molecules on human monocytes. Incubation of monocytes with purified rIFN-gamma and granulocyte macrophage-CSF, but not IL-2, IL-3, IL-4, IL-6, or TNF-alpha, also resulted in significant increases in the number of monocytes mediating cytotoxicity, suggesting that cytotoxic ability at the single cell level may be influenced by factors which effect monocyte activation and differentiation, respectively. Overall, these studies demonstrate that freshly isolated human monocytes are heterogeneous in their ability to mediate ADCC, and suggest that this functional diversity arises not from discrete subpopulations of cells, but from a continuum of maturational/activational states present within the peripheral circulation.
Radioprotective effects of the immunomodulator AS101.
Authors: Kalechman Y , Albeck M , Oron M , Sobelman D , Gurwith M , Seghal S N , Sredni B 
Published: December 2022

Abstract
Ammonium trichloro(dioxyethylene-O-O')tellurate (AS101) is a new synthetic compound previously described by us as having immunomodulating properties and minimal toxicity. Clinical trials are currently in progress with AS101 on AIDS and cancer patients. We found that AS101 was capable of inducing spleen cells and peritoneal exudate cells to secrete high quantities of CSF and IL-1. Because IL-1 has been previously described as a radioprotector and CSF may induce in vivo the proliferation of hemopoietic cells, we designed the present study in order to evaluate the effects of prolonged in vivo injections of AS101 on protection against lethal doses of irradiation, on the recovery pattern of precursor cells, and on the functioning of bone marrow (BM) and spleen cells of mice undergoing sublethal doses of treatment. We demonstrate that pretreatment with AS101 protects mice from lethal effects of ionizing radiation. AS101 was also found to significantly increase the number of BM and spleen cells, the absolute number of granulocyte macrophage-CFU and the secretion of CSF by BM cells. All were tested 9 days after sublethal dose of irradiation was administered. AS101 was found to have all of these radioprotective effects only when administered to mice before irradiation treatment. Moreover, the compound was found to enhance the proportion of CFU-S that enters the S phase of the cell cycle. These findings indicate that AS101 may be a promising agent to be used in reducing the time needed for reconstitution of hemopoietic cells after irradiation treatment.
High frequency expression of S107 VH genes by peritoneal B cells of B10.H-2aH-4bP/WTS mice.
Authors: Pennell C A , Maynard E , Arnold L W , Haughton G , Clarke S H 
Published: December 2022

Abstract
Our previous analyses of peritoneal Ly-1 B cells indicate that a high percentage express VH genes of the VH11 and VH12 families, and that this bias is due to clonal selection. The antibodies encoded by these genes bind the same hapten, phosphatidyl choline (PtC). Twenty-one of 73 hybridomas generated from fusions with peritoneal Ly-1 and Ly-1 sister population B cells of B10.H-2aH-4bp/Wts mice produce anti-PtC specific antibodies. We show here that 19 of these express VH11 and VH12 family genes and two express VH36-60 family genes. To assess whether there is a bias in VH gene use among non-PtC-specific hybridomas we analyzed the remaining 52 hybridomas for VH family expression by using VH family-specific probes in an RNA dot blot assay and by Ig mRNA sequencing. We find a seven-fold increase in the expression of the VHS107 family genes, and only slight differences in the expression of VH genes of other families relative to splenic B cells. We attribute the increase in VHS107 gene expression to clonal selection inasmuch as five of the seven VHS107+ hybridomas express the same VH gene (V11) and VL association is nonrandom. The bias in VH gene use among the entire panel of 73 peritoneal hybridomas is to the extent that approximately one-third express one of three genes: the V11 gene of the S107 family, the CH34 gene of the VH11 family, and the VH12 family gene.
IFN-alpha in vivo enhances tumor necrosis factor receptor levels on hairy cells.
Authors: Billard C , Sigaux F , Wietzerbin J 
Published: December 2022

Abstract
Hairy cell leukemia (HCL) is a preplasma B cell neoplasia that is characterized by monocytopenia and responds to IFN-alpha therapy. We investigated the expression of receptors for TNF-alpha, a monocyte-derived cytokine, on the surface of hairy cells from seven HCL patients before and after treating them with IFN-alpha. Iodinated TNF-alpha binding experiments showed the presence of high affinity TNF-alpha receptors in six patients, but no specific binding was detected in the seventh. Scatchard's analysis revealed the presence of a single class of receptors, with 130 to 1200 sites/cell (mean 420) and Kd values of 0.37 to 0.89 nM. The TNF-alpha-R complex was identified by cross-linking as a single band of 94 kDa. Treatment of the patients with 3 x 10(6) U of IFN-alpha 2a markedly increased the number of TNF-alpha-R at 24 or 48 h, without changing the Kd. In the patient who lacked receptor expression on his tumor cells, high affinity TNF-alpha-R were detected at 48 h after IFN injection. These results suggest that in hairy cells, IFN-alpha can interact in vivo with TNF-alpha, through the modulation of TNF-R.
Structural analysis of H-2Kf and H-2Kfm1 by using H-2K locus-specific sequences.
Authors: Horton R M , Hildebrand W H , Martinko J M , Pease L R 
Published: December 2022

Abstract
The H-2Kf allele and the spontaneous mutant Kfm1 have been cloned using locus-specific sequences. The mutation consists of a cluster of four nucleotide changes, resulting in amino acid substitutions at positions 95 (Leu----Ile) and 97 (Val----Arg). This finding has structural, genetic, and technical implications. The amino acid substitutions are located on the beta-strands of the antigen recognition site. Their influence on the allogeneic properties of the Kf glycoprotein is consistent with the hypothesis that alloreactivity results from alterations in the spectrum of peptides presented to T cells. These substitutions would not, however, be predicted to be directly accessible for binding to antibodies. Nonetheless, the fm1 mutant binds anti Kf alloantisera and mAb much less strongly than the parent molecule, suggesting some indirect effect of these residues on serologic phenotype. The mutant is also interesting genetically because the sequence of the mutated region is identical to the sequence of the Df gene. This implies that there is a gene conversion-like mutational mechanism operating in the H-2f haplotype. Finally, the strategy used to obtain these K-locus cDNA should prove generally useful for isolating other MHC alleles.
A novel approach to the generation of high affinity class II-binding peptides.
Authors: Sette A , Sidney J , Albertson M , Miles C , Colón S M , Pedrazzini T , Lamont A G , Grey H M 
Published: December 2022

Abstract
We have found that if core regions crucial for class II binding are incorporated in multiple copies in the same peptide molecule ("reiterative motifs"), marked enhancement of the binding capacity occurs. Isotype specificity (IAd vs IEd binding capacities) is retained in all three antigenic determinants so far analyzed (lambda rep 12-26, OVA 323-339, and hen egg lysozyme 105-120). The mechanism involved in such an effect is not clear, but experiments involving introduction of a peptide spacer between two repeated core regions do not support the notion that the effect is mediated by cross-linking of more than one MHC molecule, favoring the possibility that conformational effects or distinct subsites of interaction on the MHC molecule may be involved. Based on reiterative structures, a peptide molecule composed of only two different amino acids (Ala and His) has been produced that still retains a very high binding affinity. An 125I-radiolabeled form of this peptide has been used to demonstrate that the high binding detected is mediated by the same binding site involved in the interaction of IAd and OVA 323-339. Inhibition of Ag presentation studies further supports the immunologic relevance of the phenomena observed. Finally, we observed naturally occurring clustered binding sites in proximity of immunodominant protein regions, raising the possibility that the phenomenon might have a physiologic counterpart.
Immune responses to Herpesvirus sylvilagus infection in cottontail rabbits.
Authors: Yang W C , Hesselton R M , Sullivan J L 
Published: December 2022

Abstract
Immunologic changes produced by Herpesvirus sylvilagus infection of cottontail rabbits were investigated to evaluate this virus infection system as an animal model for EBV infection in humans. H. sylvilagus neutralizing antibodies appeared as early as 7 days after infection, peaked 2 to 4 wk postinfection and decreased to low levels by 8 to 10 wk postinfection. Complement-dependent antibodies mediating the protection of in vitro infection of monocytes and Con A-stimulated lymphoblasts with H. sylvilagus were observed as were complement-dependent cytotoxic antibodies against H. sylvilagus-infected cells. No cytolytic activity was present in sera taken either before or 3 days after infection; cytolysis was first observed 7 days after infection. The development of cytolytic antibodies appeared to be biphasic during an infection course of 12 to 16 wk. In vivo induction of a primary cytotoxic lymphocyte response to H. sylvilagus was also investigated. Splenic lymphocytes from infected animals lysed H. sylvilagus-infected skin fibroblasts; however, similar activity was not observed when PBMC or mesenteric lymph node lymphocytes were used as effector cells. H. sylvilagus-infected autologous skin fibroblasts were preferentially lysed as compared to heterologous skin fibroblasts. This virus-specific cytotoxic activity appeared 5 days postinfection and peaked 7 days postinfection. By 28 days postinfection, only low levels of cytotoxic activity were detected in spleen cells. Herpesvirus sylvilagus infection of cottontail rabbits provides an animal model for the study of lymphoproliferative disorders induced by herpesviruses.
Induction of murine lymphokine-activated killer cells by recombinant IL-7.
Authors: Lynch D H , Miller R E 
Published: December 2022

Abstract
The data demonstrate that IL-7, a cytokine that was originally identified, purified, and cloned based upon its ability to support the growth of pre-B cells in vitro, also induces proliferation and promotes the generation of lymphokine-activated killer (LAK) cell activity in populations of resting peripheral lymphoid cells. Although the kinetics of LAK induction by IL-7 (which peaked at days 6 to 8 of culture) was slower than that detected in cultures containing IL-2 (which peaked at day 4), IL-7 was significantly more effective at maintaining cytotoxic activity over longer periods of time, and greater viable cell recoveries, than was IL-2. A wide range of murine tumor target cells were found to be lysed in an MHC-unrestricted fashion by IL-7 induced LAK, but syngeneic Con A-induced lymphoblasts were not; nor were target cells from the human tumors K562 or Daudi lysed by IL-7 LAK. IL-7 LAK were induced in populations of lymphoid cells obtained from secondary lymphoid tissues (peripheral lymph nodes and spleen), but not from primary lymphoid tissues (thymus and bone marrow). LAK induced by IL-7 from unfractionated populations of lymphoid cells were completely eliminated by treatment with anti-CD8 or anti-Thy-1+C, and unaffected by treatment with anti-CD4, anti-asialo GM1 or anti-NK1.1+C. Interestingly, although no detectable CD4+ effector cells could be detected in populations of LAK generated from unfractionated populations of lymphoid cells stimulated by IL-7, they were found to be generated from populations of lymphoid cells from which CD8+ cells had been eliminated before being cultured in medium containing IL-7. These data suggest that CD4+ T cells do not normally give rise to IL-7-induced LAK unless they are first separated from CD8+ T cells. LAK induced by IL-7 appear to be distinct from LAK activity induced by IL-2 in that there is no detectable involvement of NK-like effector cells at either the precursor or effector cell stages.
Early biochemical events after MHC class II-mediated signaling on human B lymphocytes.
Authors: Mooney N A , Grillot-Courvalin C , Hivroz C , Ju L Y , Charron D 
Published: December 2022

Abstract
These studies examined the role of the MHC class II Ag in signal transduction using human B lymphocytes. Early events in signal transduction were considered including the intracellular calcium [Ca2+)i) flux, the activation of phospholipase C, and induction of protein phosphorylation. The (Ca2+)i was enhanced after incubation of B lymphocytes with several mAb anti-HLA class II and cross-linking with rabbit anti-mouse-F(ab')2. We have also demonstrated an enhancement of the (Ca2+)i in response to a suboptimal concentration of a monoclonal anti-IgM either in the presence of or after preincubation with a mAb anti-HLA class II. The activation of phospholipase C was assessed by measuring the generation of inositol phosphates in permeabilized B lymphocytes. mAb anti-HLA-class II of two different epitopes were used to demonstrate both the (Ca2+)i flux and the generation of inositol phosphates. Two-dimensional gel electrophoresis was used to investigate the phosphorylation pattern of resting B lymphocytes and the changes in the pattern after stimulation with soluble mAb anti-HLA-DR, immobilized mAb anti-HLA-DR, and PMA. In addition to the augmentation of phosphorylation observed with regard to phosphoproteins already present in resting B lymphocytes, new phosphorylations were observed after stimulation by any one of the reagents. Furthermore, stimulation by PMA did not result in an identical pattern to that observed after stimulation by mAb anti-HLA class II. An inhibition of the proliferative response to PMA was demonstrated after prestimulation of cells with immobilized mAb anti-HLA-DR, supporting the notion of a shared pathway of activation. In summary, these data demonstrate signal transduction via MHC class II Ag as assessed by three different measures of early events in human B lymphocyte activation and suggest that a protein kinase C pathway is at least partly involved.
sgp-60, a signal-transducing glycoprotein concerned with T cell activation through the T cell receptor/CD3 complex.
Authors: Reiser H 
Published: December 2022

Abstract
T cell activation depends not only on the expression of a TCR, but also on that of accessory molecules that function in cell-cell adhesion and/or signal transduction. The subject of this report is the biochemical and functional characterization of what appears to be a novel murine lymphocyte cell surface antigen, provisionally termed sgp-60. Extensive, higher-order cross-linking of this glycoprotein with an anti-sgp-60 mAb and a second-step antibody reagent results in the activation of resting CD4+ T cells in the presence of a second signal. Monovalent or bivalent engagement of sgp-60 by the anti-sgp-60 antibody results in profound and direct inhibition of anti-CD3- or Con A-driven T cell activation, whereas alternative T cell activation via the phosphatidylinositol-linked proteins Thy-1 and TAP/Ly-6A is not affected. These findings raise the possibility that the sgp-60 molecule may be specifically involved in signal transduction through the TCR/CD3 complex and thus point to an important physiologic role for this protein in CD4+ T cells.
IFN-gamma regulates the expression of the adhesion molecule ELAM-1 and IL-6 production by human endothelial cells in vitro.
Authors: Leeuwenberg J F , von Asmuth E J , Jeunhomme T M , Buurman W A 
Published: December 2022

Abstract
In this study two new in vitro effects of IFN-gamma on human umbilical vein endothelial (HUVE) cells were described. First, it was shown that the expression of the adhesion molecule ELAM-1 on activated HUVE cells can be modulated by IFN-gamma. ELAM-1 is normally not expressed by HUVE cells, but its expression can rapidly be induced by TNF, IL-1, or LPS. Maximal expression is reached after 4 to 6 h of activation, and after 24 h the expression disappeared. Whereas IFN-gamma per se did not induce expression of ELAM-1, it enhanced and prolonged the expression of ELAM-1. This enhancement occurred when IFN-gamma was added before activation as well as when added simultaneously with activation. When IFN-gamma was added 6 or 9 h after the activation, the normally ongoing reduction of expression was not only retarded, but the expression increased for at least 3 h. Moreover, IFN-gamma abrogated the refractory period for restimulation. Neither IFN-beta nor IL-6 had any effect on the expression of ELAM-1. The second effect of IFN-gamma on HUVE cells is the capacity to enhance the IL-6 production by these cells. Prestimulation as well as coincubation of IFN-gamma with TNF, IL-1, or LPS resulted in a strongly augmented production of IL-6. The effects of IFN-gamma may in vivo play a role in the regulation of an inflammatory reaction, because ELAM-1 is an adhesion molecule for neutrophils, and IL-6 has an enhancing effect on the cytotoxicity of neutrophils.
Thymic B cells from myasthenia gravis patients are activated B cells. Phenotypic and functional analysis.
Authors: Leprince C , Cohen-Kaminsky S , Berrih-Aknin S , Vernet-Der Garabedian B , Treton D , Galanaud P , Richard Y 
Published: December 2022

Abstract
Thymic cell populations from 12 patients displaying myasthenia gravis were submitted to a phenotypic and functional study. Immunofluorescence analysis of thymic sections revealed the presence in germinal centers of B lymphocytes expressing the B cell markers--CD19, CD21, IgD, or IgM. After T cell and macrophage depletion of thymic single cell suspensions, B cell-enriched populations were isolated. Enriched B cells expressed at variable levels activation markers such as CD71, 4F2, CD23, and B8.7, indicating that a marked proportion of them are activated. Moreover, addition of B cell growth factor 12kDa and to a lesser extent of rIL-2 induced a spontaneous proliferation of these B cell populations. These functional and phenotypic signs of activation may reveal the first steps of an autoimmune response against acetylcholine receptor as enriched B cell populations have the capacity to spontaneously secrete anti-acetylcholine receptor antibody.