bluuebunny/crossref_metadata_2025_split huggingface dataset:
Human Fc gamma RIII (CD16). Isoforms with distinct allelic expression, extracellular domains, and membrane linkages on polymorphonuclear and natural killer cells.
Authors: Edberg J C , Redecha P B , Salmon J E , Kimberly R P 
Published: December 2022

Abstract
Human Fc gamma RIII (CD16), a low-affinity receptor expressed on several different cell types, has a polymorphism on polymorphonuclear cells (Fc gamma RIIIPMN) identified by the NA1 and NA2 markers. Inasmuch as this polymorphism has functional consequences, an understanding of the structural biology of Fc gamma RIII may provide important insight into receptor function. We analyzed Fc gamma RIIIPMN by SDS-PAGE and found that receptor from individuals allotyped for either NA1 or NA2 contained only one protein after removal of N-linked glycosylations (19 and 21 kDa respectively) whereas receptor from NA1/2 individuals contained both bands. Because some reports indicate that digestion of Fc gamma RIII on NK cells (Fc gamma RIIINK) with N-glycanase also results in two bands on SDS-PAGE, we investigated Fc gamma RIIINK to explore the possibility of a corresponding allelic polymorphism in this receptor. Contrary to expectation, Fc gamma RIIINK from all donors irrespective of their NA allotype contained two bands (20 and 24 kDa) on SDS-PAGE after deglycosylation. In addition, those distinct epitopes on the extracellular domain of Fc gamma RIIIPMN found with mAb B73.1 and CLB gran 11 in association with the NA allotypic differences are expressed (or not expressed) on Fc gamma RIIINK independent of donor NA allotype. Fc gamma RIIIPMN and Fc gamma RIIINK differ at the protein level as they have different m.w. (glycosylated and deglycosylated), different epitopes in the extracellular domain (not attributable to tissue-specific glycosylation), and differential expression of the NA allelic protein polymorphism. Although the membrane anchor of Fc gamma RIIIPMN is a phosphatidylinositol-specific phospholipase C sensitive glycosyl-phosphatidylinositol linkage, Fc gamma RIIINK is insensitive to phosphatidylinositol-specific phospholipase C. However, a form of Fc gamma RIIINK is released from NK cells upon incubation at 37 degrees C. Thus, the basis for the two bands in Fc gamma RIIINK after N-linked deglycosylation is neither coexpression of two molecular isoforms with different membrane anchors nor an identifiable allelic polymorphism in m.w. restricted to Fc gamma RIIINK (p less than 10(-6)). The differences between the two receptors indicate that, independent of cell anchor type, PMN and mononuclear cells must have different molecular isoforms. The allelic variants, different isoforms, alternative anchor mechanisms and release processes provide for an extensive genetic and regulatory diversity in Fc gamma RIII function.
Mastoparan, a wasp venom peptide, identifies two discrete mechanisms for elevating cytosolic calcium and inositol trisphosphates in human polymorphonuclear leukocytes.
Authors: Perianin A , Snyderman R 
Published: December 2022

Abstract
Mastoparan, a tetradecapeptide toxin from wasp venom stimulates secretion in mast cells and enhances GTPase activity of several purified guanine nucleotide regulatory proteins (G proteins). This suggests that this toxin may effect cellular functions through activation of G proteins. In this report, we probed the effects of mastoparan on cytosolic calcium concentration ([Ca2+]i) and inositol trisphosphate (IP3) formation in human polymorphonuclear leukocytes (PMN). At noncytotoxic concentrations up to 35 microM, mastoparan induced a dose-dependent elevation in [Ca2+]i in PMN, as determined by the fluoroprobe Fura 2. The increase in [Ca2+]i was attained through two discrete processes involving an initial rapid and transient calcium rise followed by a slower sustained increase. The initial but not the second [Ca2+]i increase was absent in PMN pretreated with pertussis toxin. The second but not the first [Ca2+]i rise required external calcium. The kinetics of [Ca2+]i changes and dependency on extracellular calcium induced by mastoparan correlated with the production of IP3. Pertussis toxin inhibited only the initial phase of IP3 production. The ability of pertussis toxin to ADP-ribosylate Gi-like proteins in PMN membrane was potentiated in the presence of mastoparan. Thus, mastoparan activates phospholipase C in PMN through two independent mechanisms. The first pathway is similar to that induced by chemoattractant receptors in that the rapid and transient activation of phospholipase C is dependent on a pertussis toxin-sensitive Gi protein. The second pathway is delayed, sustained, insensitive to pertussis toxin, and requires extracellular calcium.
Involvement of guanine nucleotides in superoxide release by fluoride-treated neutrophils. Implications for a role of a guanine nucleotide regulatory protein.
Authors: English D , Rizzo M T , Tricot G , Hoffman R 
Published: December 2022

Abstract
Previous studies demonstrating hydrolysis of phosphatidylinositol bisphosphate (PIP2) and generation of inositol phosphates in neutrophils exposed to 20.0 mM NaF provide indirect evidence that activation of phospholipase-associated guanine nucleotide regulatory protein, a guanine nucleotide binding protein which regulates the activation of a membrane inositol-specific phospholipase C, is an early event in the neutrophil stimulus-response pathway triggered by fluoride. Consistent with this hypothesis, exposure of a plasma membrane rich preparation isolated from 32P labeled neutrophils to 20.0 mM NaF resulted in hydrolysis of labeled PIP2. Levels of other phospholipids were not affected. Inositol bisphosphate and inositol trisphosphate were detected in extracts of neutrophil plasma membranes exposed to fluoride. To further explore the involvement of guanine nucleotides in functional responses of intact neutrophils triggered by fluoride, we preincubated cells with 2-beta-D-ribofuranosylthiazole-4-carboxamide (tiazofurin), a selective inhibitor of inosine monophosphate dehydrogenase, to diminish guanine nucleotide synthesis and then compared superoxide generation induced by FMLP, PMA, digitonin, and 20.0 mM NaF to intracellular levels of guanine nucleotides. Preincubation of neutrophils for 2.5 h at 37 degrees C with tiazofurin resulted in dose-dependent depletion of GTP and GDP. Maximal depletion of guanine nucleotides required relatively high levels of tiazofurin (200 to 400 microM) and resulted in a 55 to 60% reduction of GTP and GDP. The effects of tiazofurin on guanine nucleotides levels were not observed when neutrophils were preincubated at 4 degrees C. AT 37 degrees C, tiazofurin also decreased intracellular ATP and ADP levels but adenine nucleotide depletion was less pronounced than guanine nucleotide depletion for each concentration of tiazofurin used. When tiazofurin was removed by washing cells after incubation, adenine nucleotide quickly returned to preincubation values but guanine nucleotide levels remained depressed. Addition of exogenous guanosine (200 microM) prevented tiazofurin-dependent depletion of guanine nucleotides but had no influence on adenine nucleotide depletion. Superoxide released triggered by FMLP and F- was inhibited to an extent similar to that of guanine nucleotide depletion under different conditions of preincubation. Inhibition of superoxide release was not observed if cells were preincubated at 4 degrees C, was not rapidly reversible, and was not observed when guanosine was added with tiazofurin.(ABSTRACT TRUNCATED AT 400 WORDS)
Molecular basis for a polymorphism involving Fc receptor II on human monocytes.
Authors: Clark M R , Clarkson S B , Ory P A , Stollman N , Goldstein I M 
Published: December 2022

Abstract
IgG Fc receptor II (Fc gamma RII) on human monocytes is polymorphic with respect to its appearance on gels after isoelectric focusing and with respect to its ability to mediate T lymphocyte proliferation induced by murine anti-CD3 mAb of the IgG1 isotype (i.e., its ability to bind murine IgG1). To determine the molecular basis for this polymorphism, we isolated total cellular RNA from PBMC of responders and nonresponders (defined by Leu-4-induced [3H] thymidine incorporation) and synthesized corresponding cDNA. Sequences encoding the extracellular domain of Fc gamma RII were then amplified using the Taq polymerase chain reaction. Amplified DNA fragments were cloned into pUC vectors, and sequenced. Analysis of clones from two nonresponders revealed a single base change (G for A) at position 519, which would result in the substitution of a histidine for an arginine at residue 133 in the mature Fc gamma RII protein. These findings suggest that the polymorphism involving human monocyte Fc gamma RII results from allelic variation of a single gene.
Regulation of murine lymphokine production in vivo. Ultraviolet radiation exposure depresses IL-2 and enhances IL-4 production by T cells through an IL-1-dependent mechanism.
Authors: Araneo B A , Dowell T , Moon H B , Daynes R A 
Published: December 2022

Abstract
The exposure of experimental animals to the inflammatory effects of ultraviolet radiation (UVR) is known to cause depressions in their ability to initiate and effectuate various types of cellular immune responses. Contact-type and delayed-type hypersensitivity, plus the ability to generate protective forms of anti-viral and anti-tumor immunity, are all affected by the prior exposure of normal animals to the effects of this physical agent. Presently, the cellular and molecular mechanism(s) responsible for mediating the changes in immune function observed in UVR-exposed animals is not fully understood. Herein we report that one reproducible consequence of exposing normal mice to low doses of UVR is a dramatic change in the pattern of lymphokines secreted by their activated T cells. Lymphocytes isolated from UVR-exposed donors produce/secrete greatly reduced levels of the T cell lymphokines IL-2 and IFN-gamma activation in vitro with protein Ag of the polyclonal T cell stimulant anti-CD3. The secretion of IL-4 by these lymphocyte cultures, however, is consistently elevated in comparison to normal controls. Further studies determined that a similar change in lymphokine production was induced when mice were treated with either bacterial LPS or rIL-1 beta, a cytokine known to be elevated in vivo after UVR or LPS exposure. The ability of IL-1 to facilitate a change in the capacity of T lymphocytes to produce/secrete lymphokines after in vitro activation does not appear to represent a direct effect of this cytokine on lymphocyte or accessory cell targets because addition of IL-1 beta to cultures of Ag-primed lymphocytes obtained from normal donors was incapable of altering the pattern of lymphokine production. Collectively, our present results add further support to the hypothesis that UVR-induced elevations in endogenous IL-1 are, in part, responsible for the immunomodulatory effects of UVR. These findings provide compelling evidence that UVR, plus other agents capable of endogenously stimulating the production of IL-1, may function to alter the expression of different effector mechanisms in vivo. This could be facilitated through selective reductions in lymphokines produced by Th-1-type cells (IL-2 and IFN-gamma) and a simultaneous augmentation in a lymphokine produced by Th-2-type cells (IL-4).
Identification of an acidic ribosomal protein reactive with anti-Sm autoantibody.
Authors: Nojima Y , Minota S , Yamada A , Takaku F 
Published: December 2022

Abstract
Autoantibody to Sm Ag is a highly specific marker for the diagnosis of SLE. The Sm Ag exists in the cell nucleus as part of a ribonucleoprotein complex containing five small nuclear RNA. The major immunoreactive Sm species have been reported to be three polypeptides of m.w. 28,000/29,000 (B/B') and 16,000 (D). We report here that a m.w. 21,000 peptide is another major target of anti-Sm antibody. This peptide was originally identified by Western blotting as an acidic ribosomal protein (RP21) reactive with IgG from some SLE patients. Anti-RP21 is distinct from anti-ribosomal P protein antibody (anti-P) which has been previously identified as a lupus-specific autoantibody. Cell fractionation experiments showed that RP21 existed only in the ribosomal fraction and was never detected in other cellular compartments including nuclei. However, when nuclear extracts were used as Ag sources in immunoblotting, affinity-purified anti-RP21 was found to react with m.w. 28,000 and 16,000 peptides, suggesting that anti-RP21 reactivity might be due to the cross-reaction of anti-Sm. This was further confirmed by the evidence that two kinds of murine anti-Sm mAb independently derived from MRL/lpr mouse recognized RP21. These results indicate that anti-Sm antibodies in SLE are reactive with both nuclear and ribosomal ribonucleoproteins. Previous reports have described certain similarities, i.e., antibody subclass restriction and incidence, of anti-Sm and anti-P in both humans and autoimmune mice. Our present study demonstrated a close physical association of target molecules reactive with anti-Sm and anti-P, and might, therefore, provide some clue to the origin of these two types of lupus-specific autoantibodies.
Prostaglandin E2 production is synergistically increased in cultured human glomerular mesangial cells by combinations of IL-1 and tumor necrosis factor-alpha 1.
Authors: Topley N , Floege J , Wessel K , Hass R , Radeke H H , Kaever V , Resch K 
Published: December 2022

Abstract
Both IL-1 alpha and IL-1 beta and TNF-alpha induced a time- and dose-dependent release of authentic PGE2 from cultured human glomerular mesangial cells (HMC). This release became significant only after a 4- to 6-h lag phase, and was abolished by inhibition of protein synthesis, and was not related to cell proliferation. Combinations of IL-1 and TNF-alpha when added simultaneously to HMC resulted in a dose-dependent synergistic increase in PGE2 production. These stimulatory effects were specifically inhibited by anticytokine antibodies and the synergistic effect required the simultaneous presence of both IL-1 and TNF-alpha. Arachidonic acid (AA) release experiments and measurement of cyclooxygenase activity, revealed that while both were increased by IL-1 beta and TNF-alpha alone (IL-1 beta greater than TNF-alpha), combinations of IL-1 beta and TNF-alpha resulted in only additive increases in AA release and cyclooxygenase activity. Taken together, these data suggest that stimulation of PGE2 in HMC, by combinations of these cytokines, is not rate limited by AA release or cyclooxygenase activation, but may be related to the induction of the distal enzymes controlling specific PG synthesis.
Leukotriene B4 enhances activation, proliferation, and differentiation of human B lymphocytes.
Authors: Yamaoka K A , Claésson H E , Rosén A 
Published: December 2022

Abstract
Highly purified human tonsillar B lymphocytes at different stages of activation were incubated with leukotriene B4 (LTB4). As a key marker for activation, we used the CD23 Ag. LTB4 enhanced the CD23 expression on resting B cells in synergy with B cell-stimulating factors from 4% to 50%. Maximal effect of LTB4 was observed at 10(-10) M to 10(-12) M. LTB4 also augmented the S and M phase entries as well as Ig secretion in synergy with IL-2 and IL-4. In contrast, 5S,12S-dihydroxyeicosatetraenoic acid, an isomer of LTB4, and leukotriene C4 lacked these effects. The results indicate that LTB4 amplifies lymphokine-driven activation, replication, and differentiation of human B lymphocytes.
The mapping of epitopes of the 18-kDa protein of Mycobacterium leprae recognized by murine T cells in a proliferation assay.
Authors: Harris D P , Bäckström B T , Booth R J , Love S G , Harding D R , Watson J D 
Published: December 2022

Abstract
The 18-kDa protein of Mycobacterium leprae was purified from recombinant plasmids pUL108 and pML-3 grown in Saccharomyces cerevisiae and Escherichia coli, respectively. Significant lymphoproliferative responses were observed when T cells from immunized mice were challenged in culture with purified 18-kDa protein. Synthetic peptides have been prepared that span most of the 148 amino acid residues that constitute the sequence of the 18-kDa protein and used to map epitopes recognized by T cells. When mice were immunized with 18-kDa protein and lymph node cells subsequently prepared and challenged in microculture proliferative assays by using synthetic peptides, only one region of the intact protein appeared stimulatory. This T cell epitope was located between residues 116 and 121, adjacent to an epitope between residues 110 and 115 which we have previously shown to bind the L5 mAb. Immunization of mice with peptides, and subsequent challenge of lymph node cells in assays by using the 18-kDa protein as Ag revealed that residues 111-125 were the most effective in priming responses. Furthermore, the ability of 18-kDa primed lymph node cells to recognize determinants on both M. leprae and Mycobacterium tuberculosis indicates that in addition to possessing an M. leprae-specific B cell determinant, the 18-kDa protein contains a cross-reactive T cell epitope(s).
Differential in vitro activation of CD4+CD8- and CD8+CD4- herpes simplex virus-specific human cytotoxic T cells.
Authors: Yasukawa M , Inatsuki A , Kobayashi Y 
Published: December 2022

Abstract
In order to clarify the differential activation of CD4+ and CD8+ HSV-specific CTL, we compared the characteristics of CTL generated by different methods of in vitro HSV stimulation by treatment of effectors with anti-CD4 and anti-CD8 mAb and C after the elimination of nonspecific cytotoxic effector cells. Cell-free HSV mainly activated CD4+ CTL precursors, whereas HSV-infected fibroblasts were more effective in activating CD8+ CTL precursors than CD4+ CTL precursors. In addition, limiting dilution analyses with enriched T cells from two HSV-seropositive donors revealed that the frequency of HSV-specific CD4+ CTL precursors responsive to stimulation with free HSV was approximately 1/4,000 to 6,000 CD4+ T cells, whereas that of precursors responsive to stimulation with HSV-infected fibroblasts was approximately 1/19,000 to 22,000 CD4+ T cells. Conversely, the frequency of CD8+ CTL precursors in peripheral blood responsive to stimulation with free HSV was approximately 1/28,000 to 30,000 CD8+ T cells, whereas that of precursors responsive to stimulation with HSV-infected fibroblasts was approximately 1/10,000 to 11,000 CD8+ T cells. The present data suggest that generalized viral infection due to cell-free viruses is fought mainly by CD4+ CTL, which have previously been reported to possess both cytotoxicity and helper function, and that localized viral infection on HLA class II-negative fibroblasts is prevented from spreading to adjacent cells mainly by CD8+ CTL. Such differential activation of CD4+ and CD8+ CTL seems probable when considering the protective mechanisms against viral infection.
The induction of peripheral T cell unresponsiveness in adult mice by monomeric human gamma-globulin.
Authors: Gahring L C , Weigle W O 
Published: December 2022

Abstract
Monomeric human gamma-globulin (HGG), when injected into adult mice, induces a state of specific immunologic unresponsiveness to further challenge with immunogenic forms of HGG. In this report we have directly determined the role of the thymus in the induction of HGG tolerance and the proliferative responsiveness of T cells from normal and HGG-tolerant mice. Draining lymph node T cells were isolated from HGG-tolerized and -challenged mice, and tested for their proliferative response to HGG in vitro. T cells from untreated but challenged adult CBA/CaJ and A/J mice proliferate in response to HGG, whereas such mice given monomeric HGG before challenge fail to show an HGG-specific proliferative response. APC from tolerant or nontolerant mice were equally effective in the support of Ag-specific proliferation of primed T cells. The influence of the thymus gland on HGG-induced T cell unresponsiveness was assessed by determining whether thymectomized mice could be tolerized to HGG. The results suggest that the generation of T cell tolerance to HGG is independent of thymic function as assayed by both antibody production in vivo and T cell proliferation in vitro. Unresponsiveness of T cells from tolerant mice was not a result of the presence of CD8+ cells since removal of CD8+ cells from lymph node T cells did not alter unresponsiveness to HGG in vitro. Further, mixing tolerant T cells with normal HGG-primed T lymphocytes did not inhibit proliferation of the HGG-primed cells. The results of this investigation suggest that this mouse model of tolerance to HGG represents a thymus-independent unresponsiveness of mature peripheral T cells to a nonself-Ag. Understanding the regulation of tolerance to HGG may give additional insight into the mechanisms required for the maintenance and possibly the induction of tolerance to certain self-Ag in peripheral lymphoid organs.
Kinetic analysis of effector cell recycling and effector-target binding capacity in a model of cell-mediated cytotoxicity.
Authors: Garcia-Peñarrubia P , Bankhurst A D 
Published: December 2022

Abstract
A kinetic analysis of cell-mediated cytotoxicity (CMC) at the population level based on theoretical models has been performed. This analysis considers that the binding process and the kinetics of the lytic process occur through different types of conjugates: LTn, i.e., conjugates containing one effector cell and n target cells, and LmT conjugates which contain m effector cells bound to one target cell. This allowed us to provide a quantitative description of the conjugation process, and of the binding capacities of the effector and target cells. Thus, it has been shown that these processes are governed by an equilibrium in which are involved the unbound effector and target cells, and the conjugates formed. This implies that, when the equilibrium concentrations are reached, the total number of conjugates cannot be increased from the unbound effector and target cells. However, it does not mean that the free effector cells are nonbinding, and so, when the conditions of equilibrium are perturbated (as occurs for example in CMC), all effector cells, virgin and those who have already participated in the lytic process, are able to form new conjugates. The existence of this equilibrium has also important consequences when different subpopulations are separated from an effector-target system. Thus, it explains the observation reported in the literature that, although cytometric techniques can be used to detect and count different types of conjugates, the conjugates formed cannot be separated by cell sorting (unless special precautions are taken). Finally, we have found that the number of target cells killed by one effector cell, which has been previously considered as the recycling capacity of an effector population, is in reality the result of two different mechanisms. One of these mechanisms is due to the recycling process, whereas the other (which has the same effect) is due to the multiple killing capacity of the LTn conjugates which kill more than one target cell. The average number of target cells killed per conjugate has been determined, and this allowed us to obtain the relative contributions of these two mechanisms to the total killing capacity of one effector cell. It appears that the recycling capacities of effector cell populations previously determined had been 1- to 3-fold overestimated.