bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies of protein kinase C in the rat basophilic leukemia (RBL-2H3) cell reveal that antigen-induced signals are not mimicked by the actions of phorbol myristate acetate and Ca2+ ionophore.
Authors: Cunha-Melo J R , Gonzaga H M , Ali H , Huang F L , Huang K P , Beaven M A 
Published: December 2022

Abstract
Exogenous activators of protein kinase C such as PMA in combination with a Ca2+ ionophore (A23187), cause secretion in rat basophilic (RBL-2H3) cells,but they do so through stimulatory signals that are not the same as those generated by Ag or oligomers of IgE. On the one hand, the synergy between PMA and A23187 and the suppression of Ag-mediated signals (hydrolysis of inositol phospholipids and rise in concentration of cytosolic Ca2+) by PMA were totally dependent on protein kinase C. The loss of synergistic and inhibitory actions of PMA, for example, correlated with the loss of protein kinase C (as determined by immunoblotting techniques) when cells were continuously exposed to PMA. Furthermore, the permeabilization of RBL-2H3 cells resulted in the loss of both protein kinase C and the inhibitory action of PMA, but both were retained if cells were exposed to PMA before permeabilization Ag-induced secretion, on the other hand, was not as dependent on the presence of protein kinase C. The potent inhibitor of this enzyme, staurosporine, which blocked completely the secretory response to the combination of PMA and A23187, did not inhibit Ag-induced secretion except at concentrations (greater than 10 nM) that inhibited Ag-stimulated hydrolysis of inositol phospholipids as well. Also RBL-2H3 cells still showed some secretory-response (approximately 25% of normal) to Ag when cells were depleted (greater than 98%) of protein kinase C by prolonged treatment with PMA. Previous studies have indicated that the secretory response to PMA and A23187 is much lower than that elicited by Ag when the concentrations of stimulants were matched to give the same increase in concentrations of cytosolic Ca2+.
Activation signals in human lymphocytes. Incorporation of polyunsaturated fatty acids into plasma membrane phospholipids regulates IL-2 synthesis via sustained activation of protein kinase C.
Authors: Szamel M , Rehermann B , Krebs B , Kurrle R , Resch K 
Published: December 2022

Abstract
Human PBL activated with anti-TCR/CD3 mAb express high affinity receptors for IL-2, synthesize IL-2, and subsequently proliferate. In contrast, lymphocytes activated by dioctanoylglycerol (DiC8) and ionomycin express high affinity receptors; however, no IL-2 synthesis is detectable. Anti-TCR/CD3 antibodies, as well as DiC8 cause translocation of protein kinase C (PKC) from the cytosol to the plasma membrane. In DiC8-stimulated cells translocation of PKC is detectable after 15 min, then it declines to control levels. In lymphocytes activated by antiTCR/CD3 mAb translocation of PKC is detectable after 15 min, then it declines to control levels, followed by a second, long lasting activation of the enzyme up to 4 h. Addition of polyunsaturated fatty acids to DiC8 + ionomycin-treated cells leads to IL-2 synthesis and proliferation. Incorporation of poly-unsaturated fatty acids into plasma membrane phospholipids results in long term activation of PKC. The results suggest that elevated incorporation of polyunsaturated fatty acids and thus continuous activation and translocation of PKC represents a necessary early signal for IL-2 synthesis and proliferation in human lymphocytes.
Elastase and cathepsin G of human monocytes. Quantification of cellular content, release in response to stimuli, and heterogeneity in elastase-mediated proteolytic activity.
Authors: Campbell E J , Silverman E K , Campbell M A 
Published: December 2022

Abstract
Human peripheral blood monocytes contain human leukocyte elastase (HLE) and cathepsin G (CG), serine proteinases originally described in azurophil granules of polymorphonuclear neutrophils (PMN). Immunoreactive HLE and CG of freshly harvested monocytes have been quantified in this study; to begin to elucidate potential roles for these enzymes in extracellular events, release in response to stimuli has been measured, along with proteolytic activity of monocytes toward surface-bound proteins. Our results indicate that whole-cell extracts of monocytes contain approximately 6% of the amount of HLE as do extracts of comparable numbers of PMN. In response to PMA in vitro, monocytes released 39 to 53% of their content of HLE and CG within 60 min, a fractional release greater than that of PMN. Furthermore, when phorbol-stimulated monocytes were adherent to a fibronectin-coated surface, extensive HLE-mediated proteolysis of the surface-bound protein was observed. Proteolysis by such cells in the presence of proteinase inhibitors was of considerable interest, since a subpopulation (15 to 20% of the total) expressed marked but localized proteolytic activity, possibly escaping inhibition through contact-mediated mechanisms. These data indicate that a subpopulation of freshly harvested monocytes is rich in HLE and CG (serine proteinases traditionally associated with PMN), can promptly release HLE and CG in response to stimuli, and can utilize HLE for extracellular proteolysis. Monocyte-derived serine proteinases may participate in extracellular events formerly associated with PMN-derived HLE and CG.
The major source of endogenous prostaglandin D2 production is likely antigen-presenting cells. Localization of glutathione-requiring prostaglandin D synthetase in histiocytes, dendritic, and Kupffer cells in various rat tissues.
Authors: Urade Y , Ujihara M , Horiguchi Y , Ikai K , Hayaishi O 
Published: December 2022

Abstract
The cellular localization of glutathione-requiring PGD synthetase, which catalyzes the predominant formation of PGD2 in various peripheral tissues, was investigated in adult rats by immunoperoxidase-staining with a polyclonal antibody specific for this enzyme. Although the 25 N-terminal amino acid residues of synthetase are 56% identical and 76% similar to those of several rat glutathione S-transferase subunits, the antibody cross-reacted only with synthetase in dot blotting and was nearly completely inactive with all transferase isozymes thus far purified. In Western blotting after SDS-PAGE of crude extracts of rat spleen, the antibody showed a single positive band at the same position as that of the purified enzyme (Mr = 26,000). The positive immunocytochemical stain was found in a number of histiocytes and/or dendritic cells in spleen, thymus, and Peyer's patch of intestine. The immunostain was also observed in such cells in lamina propria of the villus in small intestine and colon, in submucosal layer of stomach, and in Kupffer cells in liver. Immunoelectron microscopy confirmed that immunoreactivity of this enzyme was distributed in cytoplasm of those cells. Such immunoreactive cells were not observed in brain, spinal cord, kidney, heart, testis, and skeletal muscle. These observations suggest that PGD2 is produced by glutathione-requiring PGD synthetase localized in these types of APC in various tissues and may play a critical role in dictating the progression of immune responses.
Genetic regulation of early survival and cyst number after peroral Toxoplasma gondii infection of A x B/B x A recombinant inbred and B10 congenic mice.
Authors: McLeod R , Skamene E , Brown C R , Eisenhauer P B , Mack D G 
Published: December 2022

Abstract
Genetics of two traits, survival and brain cyst number after peroral Toxoplasma gondii infection, were studied by using recombinant inbred strains of mice derived from resistant A/J (A) and susceptible C57BL/6J (B) progenitors, F1 progeny of crosses between A/J and C57BL/6J mice, and congenic mice (B10 background). Analysis of strain distribution pattern of survival of A x B/B x A recombinant mice indicated that survival is regulated by a minimum of five genes. One of these genes appears to be linked to the H-2 complex and another is related to an as yet unmapped gene controlling resistance to Ectromelia virus. Associations of defined traits with resistance or susceptibility to Toxoplasma cyst formation were also analyzed. Cyst number is regulated by a locus on chromosome 17 within 0 to 4 centimorgans of the H-2 complex (p = 0.001). Mice with the H-2a haplotype are resistant and those with the H-2b haplotype are susceptible. This analysis also indicated that the Bcg locus on chromosome 1 may effect cyst number (map distance = 12 centimorgans, p = 0.05). Resistance to cyst formation is a dominant trait. To analyze relative roles of H-2 and Bcg loci on cyst numbers, C57BL10 (B10)-derived congenic strains of mice with known H-2 and Bcg type were studied. These studies indicated that the H-2 complex locus has the primary effect on cyst number.
Expression of human lymphocyte IgE receptor (Fc epsilon RII/CD23). Identification of the Fc epsilon RIIa promoter and its functional analysis in B lymphocytes.
Authors: Suter U , Texido G , Hofstetter H 
Published: December 2022

Abstract
Two species, Fc epsilon RIIa and Fc epsilon RIIb, of the human low-affinity receptor for IgE (Fc epsilon RII/CD23) have recently been described. They differ by only six amino acids in the cytoplasmic N-terminus and are generated by different cell-specific transcriptional start sites that lead to distinct 5'-leader sequences in the corresponding mRNA. In this study, we present the analysis of the promoter which is regulating the expression of the B cell-specific Fc epsilon RIIa. Our data show that this promoter is flanked by several long repetitive elements that are influencing transcription in the Burkitt lymphoma B cell line Jijoye. Serial deletions of the 5'-flanking region of the promoter revealed two major regulatory segments that have either inhibitory or enhancing effects on transcription. In addition, IL-4 caused a two- to four-fold up-regulation of the Fc epsilon RIIa promoter activity and the DNA element responsible was mapped within the first 250 bp of the 5'-flanking region. These results were confirmed by transferring the DNA segment containing the putative IL-4 responsive element to a heterologous thymidine kinase promoter. It was concluded that IL-4 augments the Fc epsilon RIIa expression by transcriptional regulation.
An immunodominant murine lymphoma cell surface heterodimer marks thymic progenitor subsets.
Authors: Majumdar A S , Guidos C , Kaneshima H , White J H , Marian J , Lieberman M , Weissman I L 
Published: December 2022

Abstract
mAb 1C11 was raised against the cells of retrovirus-negative, radiation-induced thymomas of C57BL/Ka mice. MAb 1C11 binds to radiation- and RadLV-induced C57BL/Ka lymphomas, to lymphomas of other mouse strains and to B-lineage tumors. The 1C11 Ag is expressed on a subpopulation of normal thymocytes that is enriched in immature cells. After fractionated x-irradiation, this percentage increases gradually during the preleukemic period, hence mAb 1C11 appears to identify a transformation-related cell surface molecule. This conclusion is supported by experiments demonstrating that flow microfluorimetry-sorted, 1C11-expressing preleukemic thymocytes progress rapidly to full neoplasia following intrathymic injection, whereas nonexpressing cells do not. Most of day-14 fetal thymocytes are as strongly positive as thymic lymphomas for the 1C11 Ag whereas Ag-activated T cell lines express moderate levels. Multiparameter flow microfluorimetry analysis shows that 1C11 is expressed predominantly on CD3-/lo thymic blast cells of three phenotypically defined subsets: CD4-8-, CD4-8+, and CD4+8+, all of which contain thymic progenitors. By immunohistochemical staining, the Ag is also found in association with epithelial cells on a variety of normal, nonlymphoid tissue, but is not detectable on heart tissue. The 1C11 antibody immunoprecipitates a disulfide-linked heterodimeric protein of 85/37 kDa and the antigenic determinant is located on the H chain of the molecule. When analyzed by SDS-PAGE under nonreducing conditions, the molecule exists as a 130-kDa protein. Enzymatic digestion of the heterodimer indicates that the H chain, but not the L chain, has at least three N-linked glycosylation sites. We propose that this novel cell surface glycoprotein may be associated with processes of differentiation and lymphomagenesis.
Detection of neutrophil-activating peptide NAP/IL-8 and NAP/IL-8 mRNA in human recombinant IL-1 alpha- and human recombinant tumor necrosis factor-alpha-stimulated human dermal fibroblasts. An immunocytochemical and fluorescent in situ hybridization study.
Authors: Mielke V , Bauman J G , Sticherling M , Ibs T , Zomershoe A G , Seligmann K , Henneicke H H , Schröder J M , Sterry W , Christophers E 
Published: December 2022

Abstract
A neutrophil-activating peptide (NAP)/IL-8 produced by LPS-stimulated human peripheral blood monocytes was biochemically purified and functionally characterized by different investigators. Work conducted in our laboratory showed that NAP/IL-8 as well as variants of this peptide are produced by a variety of cells (e.g., monocytes, T lymphocytes, endothelial cells) and that lesional psoriatic scales contain large amounts of biologically active NAP/IL-8. We now investigated human dermal fibroblasts for production of NAP/IL-8. The peptide was detected by immunocytochemistry by using the mAb 46E5. NAP/IL-8 mRNA was visualized by high resolutive fluorescent in situ hybridization with biotinylated antisense/sense RNA probes. Among the various stimuli used [human (h)rIL-1 alpha, hrTNF-alpha, hrIL-3, hr-granulocyte-macrophage-CSF, LPS, FMLP, and platelet-activating factor (PAF)] only hrIL-1 alpha (100 U/ml) and hrTNF-alpha (100 ng/ml) induced the transcription and translation of NAP/IL-8. In contrast to monocytes, LPS was without effect in cultured human dermal fibroblasts. Both NAP/IL-8 and NAP/IL-8 mRNA were found in the cytoplasm adjacent to the nucleus, but interestingly NAP/IL-8 mRNA was not restricted to the cytoplasm. In positive cells only two small bright spots were randomly distributed in the nucleus. Most likely these spots represent transcription sites where NAP/IL-8 mRNA is accumulated during gene expression. Our observations show that stimulation of dermal fibroblasts with the cytokines hrIL-1 alpha and hrTNF-alpha results in expression of IL-8.
Detection of IL-1 alpha and IL-1 beta in the supernatants of paraformaldehyde-treated human monocytes. Evidence against a membrane form of IL-1.
Authors: Suttles J , Carruth L M , Mizel S B 
Published: December 2022

Abstract
The concept of a membrane form of IL-1 arose from the observation that paraformaldehyde-treated macrophages display IL-1 bioactivity. Thus far, the biochemical characterization of a membrane form of the molecule has not been reported. In a recent publication we demonstrated that murine IL-1 alpha can be detected in the supernatants of paraformaldehyde-treated macrophages. These data indicate that the phenomenon of membrane IL-1 may result from leakage of IL-1 from inadequately fixed cells. In the current report we have extended our studies toward the examination of human IL-1 alpha and IL-1 beta. IL-1 activity can be detected in the supernatants of paraformaldehyde-treated human monocytes. Although anti-IL-1 alpha, but not anti-IL-1 beta, antibodies can efficiently block the IL-1 bioactivity, both IL-1 alpha and IL-1 beta can be found by immunoprecipitation in the supernatants of the fixed monocytes. IL-1 alpha is efficiently processed to the low m.w. form, whereas IL-1 beta remains predominantly as the inactive, precursor molecule. IL-1 is not found in the supernatants of monocyte membrane preparations, demonstrating that the leakage of IL-1 is from an intracellular, rather than membrane-bound source.
C3, C4, and the terminal complement complex differ from C1q by binding predominantly to the antigenic part of solid phase immune complexes.
Authors: Garred P , Michaelsen T E , Aase A , Mollnes T E 
Published: December 2022

Abstract
The binding of the C components C1q, C4, C3, the terminal C5b-9 complement complex (TCC) and S protein to immune complexes was studied. The hapten 5-iodo-4-hydroxy-3-nitrophenacetyl (NIP) conjugated to BSA was adsorbed to polystyrene plates and reacted with a human IgG3-mouse chimeric anti-NIP antibody. After addition of serum a dose-dependent binding of C1q, C4, C3, and TCC to the immune complexes was found. An increase in the amount of NIP-BSA was associated with an increase in the binding of TCC and a decrease in the binding of S-protein. After addition of soluble NIP only 4 to 6% of the anti-NIP antibody remained bound to the Ag. C1q showed diminished binding after addition of NIP, whereas C4, C3, and TCC quantitatively remained bound to the Ag. Binding of TCC to the immune complexes was also found in an alternative assay, in which the anti-NIP antibody was adsorbed to the solid phase before NIP-BSA and an additional layer of anti-NIP antibody were added. The supernatants from the solid phase assay were tested for C3 activation and formation of the fluid phase TCC (SC5b-9). Activation of the C3 was reflected in the fluid phase by a dose-dependent increase in C3 activation products. This was not seen for TCC despite increased binding to the solid phase.
The localization of heparin-binding fragments on human C4b-binding protein.
Authors: Hessing M , Vlooswijk R A , Hackeng T M , Kanters D , Bouma B N 
Published: December 2022

Abstract
C4b-binding protein (C4BP) is a multimeric plasma protein, which regulates the classical pathway of the C system. C4BP interacts with C C4b on a domain located in a 48-kDa chymotryptic fragment. We now demonstrate that C4BP contains heparin-binding fragments, which are located within the C4b binding domain. We have used an assay using heparin coupled to Sepharose CL-6B to show that 125I-C4BP binds to heparin in a time-dependent, saturable, and reversible manner. Binding could be inhibited by purified 48-kDa fragments and direct binding on the 48-kDa fragments to heparin-Sepharose was demonstrated by SDS-PAGE. mAb against native C4BP and the isolated 160-kDa central core fragment were evaluated for their ability to block the binding of 125I-C4BP to heparin and C4b. The relative efficacy of mAb against intact C4BP in blocking C4BP binding to heparin-Sepharose was similar to that for blocking 125I-C4BP binding to C4b. In addition, heparin blocked the binding of 125I-C4BP to C4b and vice versa. It is therefore likely that the heparin-binding fragments are localized on or close to the C4b-binding site of C4BP.
Characterization and isolation of a C-reactive protein receptor from the human monocytic cell line U-937.
Authors: Tebo J M , Mortensen R F 
Published: December 2022

Abstract
Human C-reactive protein (CRP) is an acute phase reactant that is opsonic and an activator of macrophage tumoricidal function. CRP also activates the classical C cascade. These activities suggest that CRP might interact with monocytes/macrophages via specific receptors in a manner analogous to the interaction of IgG with FcR. With the use of radio-labeled human CRP, we have observed specific binding of CRP to human blood monocytes and the human monocytic cell line U-937. Binding was saturable at a pathophysiologic concentration of CRP, with an estimated KD of 9.5 x 10(-8) M and 3.6 x 10(5) binding sites/cell. Specific binding was inhibited by polyclonal human IgG as well as an IgG1 myeloma. In the converse experiment, CRP failed to inhibit specific [125I]IgG binding. The mAb IV.3, which inhibits binding of IgG immune complexes to FcRII, did not inhibit CRP binding. A 100-fold excess of phosphorylcholine or the phosphorylcholine binding peptide of CRP (residues 47-63) failed to inhibit binding. Although human rIFN-gamma and PMA increased FcRI expression, these reagents had no affect on CRP receptor expression. A single membrane protein of 38 to 41 kDa from U-937 cells was chemically cross-linked to [125I]CRP; the cross-linking was inhibited by human IgG1 but not the IV.3 mAb. Furthermore, two membrane proteins with a Mr of 38 to 40 kDa and 58 to 60 kDa were isolated by CRP ligand-affinity chromatography. These proteins were of a distinct size from those isolated for FcRI from an IgG ligand matrix. These studies demonstrate specific binding of human CRP to a human monocytic cell line via receptors that are distinct from the IgG FcR and implicate CRP in nonspecific, preimmune host defense reaction mediated by cells of the monocytic lineage.
Expression of identical V alpha V beta gene pairs by IE-alloreactive and IE-restricted, antigen-specific T cells from MHC disparate mice. Evidence for thymic selection of V(D)J combinations.
Authors: Nakajima P B , Betz C J , Hansburg D 
Published: December 2022

Abstract
Alloreactive T cell hybridomas specific for IEk and/or IEb MHC Ag were obtained from IE-nonexpressor (IE alpha b) mice. The TCR V alpha and V beta gene segments used were identified by Northern blot and RNase protection. A large proportion (24 of 80 hybridomas tested) employed the same V alpha genes (V alpha 11.1 or V alpha 11.2) as are utilized in the IEk and IEb restricted response to the Ag cytochrome c. Of these 24 alloreactive hybridomas, 10 also expressed V beta genes utilized in the IE plus cytochrome c repertoire. Structural similarity between the two related sets of TCR indicates that V alpha segments can play a determining role in MHC specificity. These data also suggest that thymic selection based on TCR reactivity with self-MHC products acts on particular V(D)J combinations rather than on V alpha V beta pairings alone.
Frequency of B cells committed to the production of antibodies to insulin in newly diagnosed patients with insulin-dependent diabetes mellitus and generation of high affinity human monoclonal IgG to insulin.
Authors: Casali P , Nakamura M , Ginsberg-Fellner F , Notkins A L 
Published: December 2022

Abstract
Circulating autoantibodies to insulin can be detected in patients with insulin-dependent (type I) diabetes mellitus (IDDM) at the onset of the clinical disease. To characterize the autoantibody response in IDDM patients, we determined the frequency of circulating B cells committed to the production of IgM, IgG, and IgA to insulin in 12 newly diagnosed IDDM patients and, for comparison, in 9 healthy subjects and 17 insulin-treated IDDM patients. We found that B cells committed to the production of anti-insulin IgG, but not IgM, autoantibodies are present at much higher frequency in the circulation of newly diagnosed IDDM patients before insulin treatment (0.209 +/- 0.142%, mean value +/- SD of total IgG-producing cell precursors) as compared with age-matched healthy controls (0.032 +/- 0.030% of total IgG-producing cell precursors). In IDDM patients who had been treated with insulin, cells producing IgG antibody to insulin were 0.177 +/- 0.139% of total IgG-producing cell precursors. Generation of IgG mAb from B cells of IDDM patients revealed that they were monoreactive, i.e., they bound to insulin, but to none of the other Ag tested, and displayed a high affinity for insulin (Kd approximately 10(-7) moles/liter). In contrast, the IgG mAb derived from healthy subjects were polyreactive, i.e., they bound to all Ag tested, and displayed a low to moderate affinity for insulin (Kd approximately 10(-5) to 10(-6) moles/liter). These findings show that lymphocytes committed to the production of high affinity IgG autoantibodies to insulin are common in the B cell repertoire at the onset of IDDM.