bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nuclear events after activation of CD4+8+ thymocytes.
Authors: Riegel J S , Richie E R , Allison J P 
Published: January 2023

Abstract
Functionally mature T cells respond to stimulation via the Ag receptor by secretion of IL-2 and/or other lymphokines and by proliferation. However, immature CD4+8+ thymocytes do not secrete IL-2 or proliferate in response to stimulation. We have analyzed murine thymocyte populations enriched for CD4+ and CD4+8+ cells as well as the functionally mature CD4+ lymphoma C6VL-B and the CD4+8+ lymphoma 1010 for their ability to express mRNA related to early products of T cell activation signals. When stimulated with the calcium ionophore (Ionomycin) plus PMA, all the cells, regardless of their phenotype, accumulated abundant levels of c-myc mRNA. However, in contrast to the CD4+ thymocytes and C6VL-B, which accumulated abundant levels of IL-2 transcripts, neither the normal CD4+8+ thymocytes nor 1010 expressed IL-2 mRNA before or after stimulation. We have also examined these cells for the presence of the murine equivalents of two nuclear DNA-binding factors, NFAT-1 and NFIL2-A, which have been shown to be involved in IL-2 gene expression in human T cells. Our results indicate: 1) NFIL-2A binding activity is constitutively expressed in both CD4+ and CD4+8+ thymocytes and lymphomas and 2) NFAT-1 binding activity is readily detected in CD4+ thymocytes and C6VL-B, but is detected in very minimal amounts in populations enriched for CD4+8+ thymocytes and in 1010 upon activation. These results suggest that the failure of CD4+8+ thymocytes to express IL-2 mRNA upon stimulation may be in part due to the lack of inducibility of NFAT-1 binding activity, and that functional maturation of this population might be associated with acquisition of the ability to induce NFAT-1 activity.
IFN-alpha and IFN-gamma can affect both monocytes and tumor cells to modulate monocyte-mediated cytotoxicity.
Authors: Webb D S , Gerrard T L 
Published: January 2023

Abstract
IFN-alpha and IFN-gamma were found to enhance monocyte-mediated activity by acting on both tumor cells and monocytes. The addition of IFN-alpha or IFN-gamma enhanced the monocyte-mediated cytotoxicity of the human melanoma cell line, A375, as well as the human colon carcinoma cell line, HT-29. However, IFN-alpha generally induced more monocyte-mediated lysis of the A375 cells, whereas IFN-gamma induced more monocyte-mediated lysis of the HT-29 cells. These differences are, in part, due to the direct effects of the IFN on the tumor cells. Pretreatment of A375 cells with either IFN-alpha or IFN-gamma significantly enhanced their susceptibility to lysis by untreated monocytes. However, only IFN-gamma pretreatment of HT-29 cells enhanced the lysis of these cells by untreated monocytes. Differences were also observed in the activation of monocytes by IFN-alpha vs IFN-gamma with respect to their ability to induce soluble cytotoxic factors. We found that the addition of IFN-gamma and tumor cells (either the A375 or HT-29 cells) to monocytes induced TNF release, whereas IFN-alpha or IFN-gamma alone or IFN-alpha and tumor cells had no effect. Despite its presence, TNF did not appear to play a major role in the killing of either tumor cell line. However, inhibitors of H2O2-myeloperoxidase system suppressed both IFN-alpha- and IFN-gamma-induced cytotoxicity of the HT-29 cells. Thus IFN-alpha and IFN-gamma can induce both similar and distinct mechanisms of cytotoxicity in monocytes. In addition, both IFN types can increase the susceptibility of tumor cells to lysis by untreated monocytes, although sensitivity to IFN-alpha vs IFN-gamma may vary with different tumor cell lines. These differences observed between IFN-alpha and IFN-gamma on monocytes and tumor cells could have important implications for the clinical use of these cytokines.
Generation of neutralization-resistant HIV-1 in vitro due to amino acid interchanges of third hypervariable env region.
Authors: Masuda T , Matsushita S , Kuroda M J , Kannagi M , Takatsuki K , Harada S 
Published: January 2023

Abstract
Antigenic mutants of HIV-1 were isolated from three plaque-cloned viruses by the resistance of the virus to neutralizing mAb 0.5 beta against V3 domain of viral gp120, when the viruses were passaged in the presence of the antibody. However, when chronically infected MOLT-4 cells were treated with 0.5 beta mAb, recovered viruses from the 0.5 beta-treated cells showed no antigenic changes. The extent of genomic variation among antigenically distinct isolates was examined by nucleotide sequencing, which revealed a few base substitutions in 0.5 beta-binding site of all mutants isolated. The predicted amino acid replacements within 0.5 beta reacting epitope (V3 domain) causing the altered antigenicity were also identified for each of three isolates. Particularly, in one of the mutants, the most conserved Gly-Pro-Gly-Arg region located at the center of the V3 domain was changed to Gly-Gln-Gly-Arg. The radioimmunoprecipitation and synthetic peptide analyses revealed that this Pro320----Gln substitution reduced the binding affinity with 0.5 beta, although other mutations observed in the other mutants did not affect the binding affinity in radioimmunoprecipitation. We also observed that nucleic acid substitutions in the V3 domain occurred frequently in the absence of 0.5 beta mAb during our in vitro acute infection system using MT-4 cells.
Inhibition of murine monocyte proliferation by a colony-stimulating factor-1 antisense oligodeoxynucleotide. Evidence for autocrine regulation.
Authors: Birchenall-Roberts M C , Ferrer C , Ferris D , Falk L A , Kasper J , White G , Ruscetti F W 
Published: January 2023

Abstract
Using a combination of v-myc and v-ras oncogenes, we have established a growth factor-independent monocyte cell line from murine fetal liver (FL-ras/myc). Biologic and molecular characterization demonstrated that the gene for the macrophage growth factor CSF-1 and the c-fms proto-oncogene (CSF-1 receptor) are expressed in this cell line, thus suggesting autocrine regulation as a possible mechanism for the unregulated growth of these cells. To study this possibility, we used 1) mAb, to neutralize the CSF-1 protein produced by the cell line, and 2) antisense oligomers, to inhibit CSF-1 gene products by specific base-pairing of complementary nucleic acids. We report here that both approaches inhibited in vitro cell growth by 60 to 70%, whereas the combination of oligomer and mAb inhibited proliferation by 95%. However, control antisense oligomers (50% bp mismatch with CSF-1 mRNA) did not inhibit FL-ras/myc cell growth. Furthermore, the inhibitory effects of mAb and oligomers were reversible when they were removed from the media. Detection of cell-associated CSF-1 protein by immunofluorescence showed that cells treated with the antisense oligomer expressed significantly less CSF-1 protein. These results indicate that the FL-ras/myc cell line requires CSF-1 for autonomous growth and that oligomers can efficiently block production of autocrine growth factors.
IL-6 is produced by osteoblasts and induces bone resorption.
Authors: Ishimi Y , Miyaura C , Jin C H , Akatsu T , Abe E , Nakamura Y , Yamaguchi A , Yoshiki S , Matsuda T , Hirano T 
Published: January 2023

Abstract
To examine the possible involvement of IL-6 in bone metabolism, a mouse osteoblastic cell line (MC3T3-E1) and primary osteoblast-like cells from fetal mouse calvaria were cultured with several systemic and local bone-resorbing agents and their expression of IL-6 mRNA was determined. Local bone-resorbing agents such as IL-1 alpha, IL-1 beta, TNF-alpha, and LPS greatly induced IL-6 mRNA expression in both MC3T3-E1 cells and primary osteoblast-like cells. Parathyroid hormone slightly increased expression of IL-6 mRNA in primary osteoblast-like cells but not in MC3T3-E1 cells. Neither IL-6 nor 1 alpha,25-dihydroxyvitamin D3 increased expression of IL-6 mRNA in either of the osteoblast-like cells. In agreement with the expression of IL-6 mRNA, biologically active IL-6 was produced in response to the treatment with IL-1 alpha, TNF-alpha, and LPS in MC3T3-E1 cells. Adding IL-6 dose dependently stimulated the release of 45Ca from prelabeled fetal mouse calvaria. Simultaneously adding suboptimal concentrations of IL-6 and IL-1 alpha induced bone resorption cooperatively. In accord with the increase in the release of 45Ca by IL-6, there were three times as many osteoclasts in the bone sections of calvaria cultured with IL-6 for 5 days as in the controls. IL-6 slightly suppressed alkaline phosphatase activity and collagen synthesis in MC3T3-E1 cells. These results indicate that IL-6 is also produced by osteoblasts, preferentially in response to local bone-resorbing agents, and it induces bone resorption both alone and in concert with other bone-resorbing agents.
Monosodium urate crystals stimulate phospholipase A2 enzyme activities and the synthesis of a phospholipase A2-activating protein.
Authors: Bomalaski J S , Baker D G , Brophy L M , Clark M A 
Published: January 2023

Abstract
Eicosanoids are important mediators of the inflammatory response to monosodium urate crystals (MSUC) that results in gout. Phospholipase enzymes cleave fatty acids from membrane phospholipids, and this is thought to be the rate-limiting step in eicosanoid production. To understand better the mechanism of eicosanoid production in this disease, we stimulated human peripheral blood neutrophils and monocytes with MSUC and measured phospholipase enzyme activities. MSUC stimulated both intracellular and secretory phospholipase A2 enzyme activities in a time and concentration-dependent manner. Specificity was observed, as phospholipase C activities were not affected. Pretreatment with colchicine, but not aspirin, indomethacin, allopurinol, or islet activating protein, abrogated the enhanced phospholipase A2 activities. We have recently isolated and characterized a phospholipase A2 activating protein termed PLAP from synovial fluid from patients with rheumatoid arthritis, and from murine and bovine cell lines. PLAP was detected in gouty synovial fluid by immunodot blotting and ELISA assays and expressed the same characteristics as PLAP identified from other sources. To examine the role of PLAP in MSUC-induced phospholipase A2 stimulation, we treated cells with MSUC and observed an increase in immunoreactive PLAP. This response also could be blunted by colchicine, but not other drugs. Both phospholipase A2 and PLAP induced production by human monocytes of PGE2 and leukotriene B4 by neutrophils. These findings suggest that phospholipase A2 activation in response to MSUC requires an intact microtubule structure, and that phospholipase A2 and PLAP may be important modulators of at least a portion of the gouty inflammatory response.
Developmental expression of plasminogen activator inhibitor type 1 by human alveolar macrophages. Possible role in lung injury.
Authors: Chapman H A , Yang X L , Sailor L Z , Sugarbaker D J 
Published: January 2023

Abstract
Urokinase activity is regulated by the specific endogenous plasminogen activator inhibitors type 1 (PAI-1) and type 2 (PAI-2). One of these inhibitors, PAI-1, has been directly implicated in connective tissue metabolism by virtue of its ability to bind extracellular matrix proteins. Because the normal lung is relatively rich in urokinase and abnormalities in urokinase activity have been associated with fibrotic lung diseases, we have explored the possibility of local production of PAI-1 and PAI-2 in human lung. Reverse transcription and subsequent amplification by the polymerase chain reaction of total lung RNA revealed PAI-1 mRNA in each of three normal samples and in two specimens from patients with the adult respiratory distress syndrome (ARDS). In situ hybridizations of lung biopsy specimens from a patient with ARDS with cRNA probes to PAI-1 and PAI-2 indicated that alveolar macrophages express PAI-1 mRNA during the acute injury phase. Subsequent reverse transcription and PCR amplification of normal human monocyte and alveolar macrophage mRNA revealed that neither cell type expressed mRNA for urokinase inhibitors. However, after 24 h stimulation with endotoxin in vitro, monocytes were strongly positive for PAI-2 but negative for PAI-1 mRNA whereas, under the same conditions, alveolar macrophages exhibited mRNA for both PAI-1 and PAI-2. Metabolic labeling of endotoxin-stimulated alveolar macrophages with 35S-methionine followed by immunoprecipitation with PAI-1 and PAI-2 antibodies revealed that macrophages synthesized both PAI-1 and PAI-2. As judged by immunoprecipitation and functional studies, PAI-2 was found to be the major intracellular PA inhibitor whereas PAI-1 was found to predominate outside the cell. Thus, mononuclear phagocytes exhibit a developmental potential for PAI-1 expression. The release of PAI-1 by stimulated macrophages, as observed in the setting of ARDS, may be one mechanism by which these cells promote connective tissue accumulation.
Leukotriene B4 potentiates the expression and release of Fc epsilon RII/CD23, and proliferation and differentiation of human B lymphocytes induced by IL-4.
Authors: Dugas B , Paul-Eugene N , Cairns J , Gordon J , Calenda A , Mencia-Huerta J M , Braquet P 
Published: January 2023

Abstract
This study documents the influence of leukotriene (LT) B4 on human B lymphocyte responses. Incubation of freshly isolated B lymphocytes with LTB4, but not LTC4, induced a slight but significant, time- and dose-dependent increase in the surface expression of Fc epsilon RII/CD23 and class II MHC Ag and in the release of soluble CD23. These changes were maximal at 10 nM LTB4 after an incubation period of 48 h. When B lymphocytes were preactivated in vitro with Staphylococcus aureus Cowan strain I (SAC), neither LTB4 nor LTC4 was able to promote proliferation and/or IgG and IgM secretion. In contrast, when resting B lymphocytes were stimulated with a suboptimal concentration (3 U/ml) of IL-4, LTB4, but not LTC4, potentiated both the Fc epsilon RII/CD23 and the class II MHC antigen expression, and the release of soluble CD23 in a dose-dependent manner, without affecting the kinetics of these responses. Furthermore, LTB4, but not LTC4, amplified both the proliferative response and the IgG and IgM secretion induced by addition of a suboptimal dose of IL-4 (3 U/ml) to SAC-preactivated B lymphocytes. Again, LTB4 did not modify the kinetics of the proliferative response promoted by IL-4. Although LTB4 potentiated IL-4-induced IgG and IgM secretion from SAC-activated B lymphocytes, no production of IgE was observed. These data indicate that LTB4 could play a regulatory role in the modulation of IL-4-induced signaling in human B lymphocytes.
Maturation-related changes in the expression of Fc gamma RII and Fc gamma RIII on mouse mast cells derived in vitro and in vivo.
Authors: Katz H R , Arm J P , Benson A C , Austen K F 
Published: January 2023

Abstract
The expression and function of Fc gamma RII and Fc gamma RIII on three mouse mast cell populations that differ in maturity as assessed by secretory granule constituents were analyzed by cellular and immunochemical approaches. As quantified by flow cytometric analysis of the binding of the rat 2.4G2 anti-Fc gamma RII/III mAb, mouse serosal mast cells (SMC) purified from the peritoneal cavity expressed more receptors per cell than did mouse IL-3-dependent, bone marrow culture-derived mast cells (BMMC), which are progenitors of SMC. Coculture of BMMC with mouse 3T3 fibroblasts for 2 wk, which alters the secretory granule composition toward that of SMC, also increased receptor epitope expression to a level equivalent to that of SMC. As assessed by rosette assays with mouse mAb to SRBC, all three mast cell populations bound IgG1, IgG2a, and IgG2b, essentially all binding was inhibited by 2.4G2 antibody, and greater quantities of the antibody were required to block immune adherence by cocultured mast cells and SMC as compared with BMMC. Immunoprecipitation and SDS-PAGE analysis of Fc gamma RII and Fc gamma RIII from BMMC, cocultured mast cells, and SMC that were surface radiolabeled with Na125I revealed predominant native forms of 62, 57, and 56 kDa, respectively, and an additional surface form of 43 kDa in SMC. Removal of N-linked carbohydrate from immunoprecipitates demonstrated that BMMC expressed peptide cores of 38 kDa (Fc gamma RII-1 gene product) and 31 kDa (Fc gamma RII-2 gene product), and barely detectable amounts of a 28-kDa (Fc gamma RIII gene product) core. The expression of all three was increased by coculture with 3T3 fibroblasts, consistent with the increased expression of their common epitope by cytofluorographic analysis. SMC expressed primarily the Fc gamma RII-1 and some Fc gamma RIII gene product. Thus, the three populations of mast cells express different amounts and ratios of the Fc gamma RII and Fc gamma RIII gene products, and maturation of BMMC during coculture with fibroblasts in vitro and in the peritoneal cavity in vivo augments cell-surface expression of the receptors and immune adherence function.
Failure to detect IL-3-binding sites on human mast cells.
Authors: Valent P , Besemer J , Sillaber C , Butterfield J H , Eher R , Majdic O , Kishi K , Klepetko W , Eckersberger F , Lechner K 
Published: January 2023

Abstract
IL-3, a pleiotropic lymphokine, has been termed mast cell growth factor because it promotes growth and differentiation of murine mast cells. Murine mast cells, in turn, express cell surface receptors for IL-3. Human rIL-3 has been shown to induce proliferation and differentiation of human basophils and to activate basophils via high affinity binding sites. To investigate whether human mast cells express IL-3R, binding studies with 125I-radiolabeled human rIL-3 were performed on HMC-1, a novel human mast cell line, and on pure populations (i.e., 93 to 99% purity) of human tissue mast cells obtained with mAb and C from dispersed lung (n = 2). Unexpectedly, neither enriched human lung mast cells nor HMC-1 cells bound radiolabeled human rIL-3 specifically. Moreover, human rIL-3 failed to promote uptake of [3H]thymidine, synthesis of histamine, histamine releasability, or changes in expression of mast cell differentiation Ag (YB5B8, CD54/ICAM-1, CD9/p24, CD33/gp67) on either human lung mast cells or HMC-1 cells. It is hypothesized that the fundamental difference in the biologic response to IL-3 between human and murine mast cells is due to a loss during evolution of mast cell high affinity IL-3 binding sites.
Class I MHC genes and CD8+ T cells determine cyst number in Toxoplasma gondii infection.
Authors: Brown C R , McLeod R 
Published: January 2023

Abstract
To determine roles of MHC class I and II genes in protection against Toxoplasma gondii, H-2 congenic and mutant mice were infected perorally with bradyzoites of T. gondii and brain cysts were enumerated 30 days later. As B10 mice (H-2b) are cyst susceptible and B10.A mice (H-2a) are cyst resistant, B10 congenic mice having the same alleles but different H-2 haplotypes were used to locate the controlling gene. Genes located at H-2L (i.e., class I genes) were found to regulate the number of brain cysts which form following peroral infection with T. gondii (p less than 0.001) with Ld being resistant and Lb being susceptible. The regulatory function of the H-2L gene product was confirmed through the study of D mutant (dm) mice. B10.D2-H-2dm1 (dm1) mice have a gain-loss mutation in Dd and Ld (i.e., recombination of Ld and Dd) and BALB/c-H-2dm2 (dm2) mice have a deletion of the Ld gene. Both these dm strains were cyst susceptible (p less than 0.001). These results provide the first direct evidence that class I genes regulate numbers of T. gondii cysts that form. In vivo ablation of CD8+ T cells with mAb YTS 169.4 converted cyst resistant B10.BAR12 mice to cyst susceptible. This result is consistent with a role for MHC restricted CD8+ cytotoxic (or suppressor) T cell regulation of cyst formation. A mutation in Ia in B6.C-H-2bm12 (bm12) mice amplified cyst numbers in susceptible mice, which is consistent with the importance of helper/inducer T cells in the induction of cytotoxic T cells. These findings are relevant to understanding the complex immunologic mechanisms that protect against T. gondii infection, development of protective preparations, and provide a conceptual basis for determining whether similar immunogenetic regulation of susceptibility is also operative in humans.
cDNA sequences encoding rabbit latent kappa 1 b5 and b6 Ig L chains.
Authors: Ishaq M , Wolf B , Dreher K 
Published: January 2023

Abstract
Regulation of rabbit Ig C kappa 1 L chain gene expression is thought to be under allelic control. Four nominal allotypic variants designated b4, b5, b6, and b9 have been found to be co-dominantly expressed at the C kappa 1 gene locus. Latent allotypes are nonallelic and appear as unexpected and transitory molecules in the serum as well as on B cell surfaces. To determine the mechanism of latent kappa 1 allotype expression, rabbits were initially induced to produce latent b5 and b6 allotypes by infection with Trypanosoma brucei and RNA was extracted from the lymph nodes of these rabbits. The polymerase chain reaction using allele specific oligonucleotide primers was used to detect and amplify the mRNA encoding the latent b5 and b6 sequences. Nucleotide sequence analysis of the cloned products revealed that the latent b5 and b6 cDNA sequences were identical to their nominal allelic counterparts, b5 and b6, respectively. Thus, the identification of transcripts encoding latent b5 and b6 sequences rules out serologic artifacts and idiotypic mimicry as explanations of latent allotype expression.
Isolation of a novel tumor protein that induces resistance to natural killer cell lysis.
Authors: Serrano R , Yiangos Y G , Solana R , Sachs J A , Pena J 
Published: January 2023

Abstract
The human metastatic tumor cell line CAP-2, produces a soluble factor that induces resistance to NK lysis of K-562 susceptible leukemia cell line, and does not inhibit the cytotoxic capacity of effector cells. The use of sequential HPLC, hydrophobic interaction chromatography, and reverse phase chromatography, coupled with cytotoxic assays, resulted in the isolation and separation to homogeneity of a novel protein responsible for this biologic activity. Size estimation studies based on TSK HPLC columns showed that this protein has a mass of 8 to 12 kDa. The amino acid composition analysis of the CAP-2 protein calculated from HPLC chromatograms shows that this protein contains around 108 amino acids. Subsequent gas phase sequence analysis, however, was hampered because the N terminus of this protein was blocked and therefore unsuitable for sequencing by Edman degradation. The functional studies showed that the NK lysis-resistance activity of the CAP-2 protein is mediated by interaction with and nonspecific binding to NK target cells. The lymphokine-activated killer and macrophage-mediated cytotoxicity and mitogen-induced proliferation is not affected. Unexpectedly, the CAP-2 protein appears to be mitogenic to its own cell line. Thus, the induction of NK lysis-resistance and the mitogenic activity showed by CAP-2 protein could contribute to the tumor growth and metastatic establishment.