bluuebunny/crossref_metadata_2025 huggingface dataset:
Th1 and Th2 clones differ in their response to a tolerogenic signal.
Authors: Gilbert K M , Hoang K D , Weigle W O
Published: December 2022

Th1 and Th2 clones specific for human gamma globulin (HGG) were compared and shown to differ in terms of the effects of tolerance induction on Ag-induced proliferation and helper activity. In developing a method to induce tolerance, splenic APC that had been pulsed with HGG and then fixed with 0.15% paraformaldehyde (HGG-FAPC) were used as a means to present Ag to the Th clones in the absence of costimulatory signals. Both Th1 and Th2 clones recognized HGG-FAPC as evidenced by their ability to proliferate to HGG-FAPC. Unlike Th2, Th1 proliferated to HGG-FAPC only in the presence of T cell-depleted allogeneic spleen cells as a source of accessory cell signals. The inability of Th1 cells to proliferate in the absence of costimulatory signals was due to Ag-specific inactivation: Th1 clones preincubated with HGG-FAPC were unable to proliferate when recultured with HGG and irradiated APC. In contrast to Th1 clones, Th2 clones showed no decrease in their Ag-induced proliferative capacity after exposure to any concentration of HGG-FAPC. However, when examined by using a second assay system, that of providing help for anti-HGG antibody production by primed B cells, Th2 preincubated with HGG-FAPC were markedly inhibited (up to 90%) in their ability to provide help. Preincubation with HGG-FAPC also inhibited the helper activity of the one Th1 clone that was found to induce a significant secondary antibody response. Taken together, the results suggest that exposure of Th1 to tolerogen in the form of HGG-pulsed fixed APC inactivates Th1 proliferative capacity, and possibly Th1 helper activity as well. Exposure of Th2 cells to a tolerogen suppresses the mechanism by which the Th2 cells provide Ag-induced B cell help, but does not inhibit the mechanism by which they proliferate to HGG. Furthermore, the results define a model that incorporates Ag processing as well as Ag presentation in the induction of tolerance in vitro.
Growth of immature (double negative) rat thymocytes in the presence of IL-1.
Authors: Gotlieb W H , Takacs L , Young H A , Gusella L , Durum S K
Published: December 2022

It is unclear which growth factors, if any, are involved in the growth and differentiation of immature T cells in the thymus. Because IL-1 has been previously implicated in thymocyte proliferation, we examined the effects of IL-1 on precursor thymocytes, the CD4-CD8- or double-negative (DN) cells. We show that IL-1 (together with Con A) is a growth factor for DN, TCR- alpha beta-cells in vitro. After 5 days of culture in IL-1 and Con A, a number of phenotypic changes were observed and two subsets of DN cells were distinguished. One subset expressed full length TCR-alpha and -beta mRNA and surface alpha beta TCR, the other expressed low levels of full length TCR-gamma together with high levels of full length TCR-delta mRNA. Thus, DN cells are induced by IL-1 and Con A to proliferate and express TCR without parallel acquisition of CD4 or CD8 markers. These data suggest that IL-1 drives early steps of intrathymic T cell differentiation.
Purification and characterization of intraparenchymal lung lymphocytes.
Authors: Abraham E , Freitas A A , Coutinho A A
Published: December 2022

We analyzed phenotypic and functional characteristics of intraparenchymal pulmonary lymphocytes in mice. As determined by flow cytometry, approximately 30% more T cells than B cells were found. Nearly all T cells bore the alpha beta TCR, most of which stained with either CD4+ or CD8+, although small numbers of double-negative T cells were present; the CD8+/CD4+ ratio was approximately 0.37. While practically all B cells bore surface IgM, and no IgA+ cells were found, and approximately more than 80% of the plasma cells produced IgA. Approximately half of the LPS-responsive cells produced IgA. Pulmonary B cell clonal precursors specific for the autoantigen, transferrin, were present in higher frequencies than those specific for the bacterial antigens, levan and Pseudomonas aeruginosa polysaccharide type I, or those producing antibodies against OVA. These results demonstrate that a distinct population of lymphocytes is present in the lungs.
Simian T cell leukemia virus type-1-specific killer T cells in naturally infected African green monkey carriers.
Authors: Yoshimura N , Nakamura H , Ishikawa K , Noda Y , Honjo S , Hayami M
Published: December 2022

Studies were made on the cellular immunity of 13 African green monkeys (Cercopithecus aethiops) naturally infected with Simian T cell leukemia virus type 1 (STLV-1), closely related to human T cell leukemia virus type 1. They were classified into 3 groups: 1) progressed carrier, 2) carrier, and 3) normal control. This grouping was made according to their hematologic features, i.e., number of peripheral white blood cells, existence of blastoid cells, presence of STLV-1 Ag on PBL and anti-STLV-1 antibody titers. None of the STLV-1 carriers showed any clinical signs, but STLV-1-specific killer T cells was detected in these PBL without in vitro stimulation. In vitro studies on Ag stimulation showed that the STLV-1-specific killer T cells had been fully activated in vivo, and that no augmentation of in vitro stimulation with STLV-1 Ag was necessary, and that primary in vitro stimulation of normal control PBL was not sufficient to induce specific killer T cells. In addition NK cell activity in PBL of infected monkeys were significantly higher than those in the uninfected.
Functional activation of human neutrophils by recombinant monocyte-derived neutrophil chemotactic factor/IL-8.
Authors: Djeu J Y , Matsushima K , Oppenheim J J , Shiotsuki K , Blanchard D K
Published: December 2022

Monocyte-derived neutrophil chemotactic factor (MDNCF)/IL-8, a novel cytokine, distinct from IL-1 and TNF was recently purified and cloned. This study was performed to investigate the biologic effect of recombinant MDNCF/IL-8 on human polymorphonuclear neutrophils (PMN) by assessment of their growth inhibitory activity against Candida albicans. The chemoattractant, FMLP was used as a positive control. We demonstrated that MDNCF/IL-8, similar to FMLP, effectively enhanced PMN-mediated anti-Candida activity. MDNCF/IL-8, from 1.0 to 1000 ng/mol, enhanced PMN-mediated anti-Candida activity, whereas FMLP was effective from 10(-10) to 10(-7) M. The optimal dose of MDNCF/IL-8 for PMN stimulation was 10 ng/ml which equalled the optimal chemoattractant dose. MDNCF/IL-8 itself, like FMLP, had no direct effect on Candida growth at any concentration and it stimulated antifungal activity only in PMN but not in monocytes. Interestingly, MDNCF/IL-8 failed to stimulate directly the production of superoxide from PMN or prime the respiratory burst of PMN exposed to FMLP. However, MDNCF/IL-8 was capable of releasing azurophilic enzymes from cytochalasin B-treated PMN into the extracellular space. Enhancement of PMN anti-Candida activity and release of azurophilic enzymes from PMN by MDNCF/IL-8 were inhibited in the presence of colchicine, which is a known inhibitor of degranulation. These results suggest that MDNCF/IL-8 induced antifungal action of PMN via oxygen-independent pathways. Furthermore, MDNCF/IL-8 induction of anti-Candida action by PMN was inhibited by pretreatment with Bordetella pertussis toxin, suggesting that enhancement of PMN antifungal activity by MDNCF/IL-8, as well as by FMLP, may be mediated by a GTP-binding protein.
Inhibitors of C1q biosynthesis suppress activation of murine macrophages for both antibody-independent and antibody-dependent tumor cytotoxicity.
Authors: Leu R W , Zhou A Q , Shannon B J , Herriott M J
Published: December 2022

The inhibitors of C1q biosynthesis and secretion, 3,4-dehydro-DL-proline (DHP) and 2,2'-dipyridyl, were previously shown to suppress murine macrophage FcR-dependent phagocytosis and cytolysis of IgG-opsonized RBC targets. Inasmuch as non-antibody macrophage activators also bind C1q to initiate C1 activation, we determined the effects of these same inhibitors of C1q biosynthesis on activation of macrophages for antibody-independent, nonspecific tumor cytotoxicity by lipid A and a variety of other non-antibody activators. Preexposure of mouse inflammatory peritoneal macrophages to either DHP (0.5 to 2.5 mM) or 2,2'-dipyridyl (0.1 to 0.3 mM) for 24 h produced a dose-related suppression of their response to activation by lipid A to mediate tumor cytotoxicity of L1210 mouse leukemia targets. Inhibition of C1q secretion by DHP-treated macrophages was confirmed both by a complement hemolytic assay and by autoradiographic analysis of [35S]methionine-labeled culture supernatants. DHP-treated macrophages were inhibited in their response to direct activation and triggering of IFN-gamma-primed macrophages by lipid A, Poly I:C, and cobra venom factor for tumor cytotoxicity. DHP inhibited macrophage activation for antibody-dependent cellular cytotoxicity of L1210 tumor targets mediated by antitumor target IgG. The addition of exogenous purified C1q (2 micrograms/ml) to macrophages after DHP treatment, reconstituted their response to activation for both antibody-independent and antibody-dependent tumor cytotoxicity. Our results indicate that C1q synthesis and secretion by effector macrophages is a prerequisite for the initiation of their activation by both immune complex and by non-antibody agents that also bind C1q. It now appears that macrophage-derived C1q may act as an auxiliary amplification signal for autocrine-like modulation of the initiation of macrophage activation by both the antibody-dependent and independent pathways.
C4b-binding protein and a 60,000-Dalton plasma protein share antigenic determinants with membrane cofactor protein of complement.
Authors: Seya T , Nagasawa S , Atkinson J P
Published: December 2022

Membrane cofactor protein (MCP) of the C system is a widely distributed regulatory molecule with C3b/C4b binding and factor I-dependent cofactor activity. A rabbit polyclonal antibody was raised against purified human MCP, and it was found to also immunoprecipitate C4b-binding protein (C4bp). Other related complement regulatory proteins, factor H, C3b/C4b receptor, and decay-accelerating factor, were not recognized by this polyclonal antibody to MCP. The cross-reactive epitope was sensitive to reduction with 2-ME and about 3% of the anti-MCP antibody reacted with C4bp. The amino-terminal 48,000-Da, chymotryptic fragment of C4bp was recognized by the antibody to MCP. This fragment of C4bp contains a seven-amino acid peptide that is identical, in its sequence and its location in the third short consensus repeat, to one found in MCP. Two polyclonal antibodies to C4bp, one raised to native and the other to reduced C4bp, did not cross-react with MCP. In addition to this one-way cross-reaction with C4bp, a protein with a m.w. of approximately 60,000 (p60) was found in two of three C4bp preparations that also cross-reacted with antiserum to MCP. p60 was present in trace quantities in the C4bp preparation and was successfully isolated from plasma by C3b affinity chromatography. Its Mr was distinct from that of MCP and other known C3b/C4b binding proteins. Furthermore, p60 was isolated by two different procedures and such material possessed no detectable cofactor activity. Based on these results, p60 is a plasma C3b-binding protein that shares epitopes with C4bp and MCP, and is probably not a soluble form of MCP.
An indirect pathway of receptor-mediated 1,2-diacylglycerol formation in mast cells. I. IgE receptor-mediated activation of phospholipase D.
Authors: Gruchalla R S , Dinh T T , Kennerly D A
Published: December 2022

The current studies explore the role of phospholipase D (PLD) in mast cell activation. Although most investigators believe that receptor-mediated accumulation of 1,2-diacylglycerol (DAG) occurs by phospholipase C hydrolysis of phosphoinositides, our previous work indicated a modest role for these substrates and suggested that phosphatidylcholine (PC) is the more likely substrate. PLD cleaves the terminal phosphodiester bond of phospholipids to yield phosphatidic acid (PA), but in the presence of ethanol, it transfers the phosphatidyl moiety of the phospholipid substrate to ethanol producing phosphatidylethanol (PEt); a reaction termed transphosphatidylation. In purified rat mast cells prelabeled with [3H]arachidonic acid, [3H]palmitic acid, or 1-O-[3H]alkyl-lysoPC, a receptor-associated increase in PLD activity was initially suggested by the rapid accumulation of labeled PA, although other mechanisms might be involved. PLD activity was assessed more directly by the production of labeled PEt by PLD-mediated transphosphatidylation in the presence of ethanol. IgE receptor cross-linking resulted in a 3- to 10-fold increase in PLD activity during the 10 min after stimulation, approximately 50% of which occurred during the first two min. PEt formation was dependent on the concentration of ethanol and was maximal at 0.5%. At concentrations of ethanol greater than or equal to 0.2%, receptor-dependent formation of PA was reduced suggesting that the ethanol promoted transphosphatidylation at the expense of hydrolysis. The dose-related decline in PA accumulation seen in the presence of ethanol was similar to ethanol-mediated inhibition of exocytosis suggesting that receptor-mediated PA formation may be of regulatory importance. These observations indicate that PLD-mediated formation of PA occurs in stimulated mast cells and, in conjunction with separate findings of PA phosphohydrolase conversion of PA to DAG in mast cells, suggest that a major mechanism of DAG formation during mast cell activation is PC----PA----DAG.
Chemotactic factor inactivator interaction with Gc-globulin (vitamin D-binding protein). A mechanism of modulating the chemotactic activity of C5a.
Authors: Robbins R A , Hamel F G
Published: December 2022

Chemotactic factor inactivator (CFI) can decrease the neutrophil chemotactic activity of C5a. Gc-Globulin (GcG) can function as a cochemotaxin for C5a by binding to C5a or C5a des Arg and enhancing its chemotactic potency. We hypothesized that CFI might interact with GcG and thus decrease the chemotactic activity of C5a. CFI was found to markedly inhibit the neutrophil chemotactic activity of partially purified C5a containing GcG (p less than 0.01). Addition of GcG was able to reverse the capacity of CFI to inhibit C5a-directed neutrophil chemotaxis (p less than 0.01). CFI had no significant effect on neutrophil chemotaxis when incubated with C5a depleted of GcG or C5a des Arg. CFI was also able to inhibit the interaction of C5a with GcG adsorbed to plastic. To determine if CFI interacted with GcG, a sandwich ELISA was used. These ELISA tests demonstrated that CFI directly interacted with GcG in a dose-dependent manner that was both heat and pH sensitive. To investigate the possibility of enzymatic degradation of C5a by CFI, CFI preparations were analyzed for carboxypeptidase activity, aminopeptidase activity, and for the capacity to cleave dansylated C5a. No enzymatic activity or cleavage was observed. Furthermore, the direct interaction of CFI with C5a and C5a des Arg was assessed by ELISA tests and column chromatography and no interaction was observed. These results suggest that CFI modulates C5a-directed neutrophil chemotaxis by interacting with GcG and preventing GcG from enhancing the chemotactic potency of C5a.
The predominance of CD8+ T cells after infection with measles virus suggests a role for CD8+ class I MHC-restricted cytotoxic T lymphocytes (CTL) in recovery from measles. Clonal analyses of human CD8+ class I MHC-restricted CTL.
Authors: van Binnendijk R S , Poelen M C , Kuijpers K C , Osterhaus A D , Uytdehaag F G
Published: December 2022

Stimulation of PBMC, in children recovering from acute measles, with autologous EBV-transformed and measles virus (MV)-infected lymphoblastoid cell lines (B-LCL) expanded primarily MV-specific CD8+ T cells. A large number of CD8+ T cell clones were obtained either by passaging of bulk cultures at limiting dilutions or by direct cloning of PBMC without previous stimulation in bulk culture. The MV-specific CD8+ T cell clones responding in a proliferative and a CTL assay were found to be class I MHC restricted. In contrast, CD4+ MV-specific T cell clones, which were generated by the same protocol, recognized MV in association with class II MHC molecules. Analysis of processing requirements for Ag presentation to CD8+ and CD4+ T cell clones, measured by the effect of chloroquine in a proliferative T cell response, revealed that both types of T cells recognized MV Ag processed via the endogenous/cytoplasmic pathway. Thus, these studies indicate that, as in most other viral infections and in contrast to previous suggestions, the class I MHC-restricted CTL response by CD8+ T cells may be an important factor in the control and elimination of MV infection. Therefore, the role proposed for CD4+ class II-restricted T cells in recovery from measles needs to be reevaluated.
Induction of human B cell differentiation by Fc region activators. II. Stimulation of IL-6 production.
Authors: Morgan E L , Hobbs M V , Thoman M L , Janda J , Noonan D J , Kadar J , Weigle W O
Published: December 2022

Fc region fragments derived from the enzymatic cleavage of human IgG have been shown to induce human peripheral blood-derived B cells to differentiate into Ig secreting cells (ISC). The synthetic peptide p23, corresponding to residues 335 to 357 in the Fc region of human IgG1, represents a region of the molecule responsible for stimulation of ISC formation. Fc region-induced ISC formation requires at least two signals; one supplied by Fc region activators and one supplied by a T cell-derived factor(s). In this report we show that the coculture of human PBMC with pFc' or p23, results in the release of factor(s) that resemble IL-6 in its pattern of biologic activity. This conclusion is based on the observations that supernatants from Fc region-stimulated PBMC cultures contained increased levels of elements that scored as positive in two assays for IL-6: the B9.9 hybridoma growth and the CESS cell differentiation assays. Moreover, RNA from Fc region-stimulation PBMC contained increased levels of IL-6 cDNA-hybridizable elements. Finally, it was observed that rabbit anti-IL-6 inhibited the ability of supernatants derived from Fc region-stimulated PBMC cultures to induce B9.9 cell proliferation as well as p23-induced ISC formation in intact PBMC cultures. Fc region fragments induce both monocytes and T cells to produce IL-6. Taken together, these results indicate that IL-6 is produced in Fc region-stimulated PBMC cultures and is involved in B cell activation by these activators.
A monoclonal antibody that detects a novel antigen on endothelial cells that is induced by tumor necrosis factor, IL-1, or lipopolysaccharide.
Authors: Wellicome S M , Thornhill M H , Pitzalis C , Thomas D S , Lanchbury J S , Panayi G S , Haskard D O
Published: December 2022

The alteration in the surface of endothelial cells (EC) in response to cytokines is likely to be of great importance to the regulation of cell migration and thereby to the evolution of inflammatory processes. We have generated three mAb against cytokine inducible Ag on EC. Whereas mAb 1.2B6 and 6.5B5 were found to react with ELAM-1 and ICAM-1, respectively, mAb 1.4C3 reacted with a novel molecule that showed a different pattern of expression from ELAM-1 or ICAM-1 after stimulation of EC by TNF, IL-1, or LPS. Like ELAM-1, the 1.4C3 Ag was minimally expressed on resting EC, whereas ICAM-1 was moderately expressed. After stimulation with IL-1, TNF, or LPS, ELAM-1 expression was maximal after 4 to 6 h, 1.4C3 Ag after 6 to 10 h, and ICAM-1 after 10 to 24 h. The duration of 1.4C3 expression was intermediate between ELAM-1 and ICAM-1, and was more prolonged in response to TNF than IL-1 or LPS. Whereas the expression of the three Ag showed a similar dose response to varying concentrations of IL-1 or LPS, EC required a 10-fold higher concentration of TNF for half maximal expression of ELAM-1 than for half maximal expression of 1.4C3 Ag or ICAM-1 (5 ng/ml compared to 0.5 ng/ml). Of the three Ag, only ICAM-1 was enhanced by IFN-gamma. SDS-PAGE under reducing conditions showed the 1.4C3 Ag to migrate as a single band with a relative molecular mass of approximately 95 kDa. mAb 1.4C3 adds to our understanding of the kinetics of the EC response to different cytokines and will be useful in studying the regulation of EC activation. Furthermore, the 1.4C3 molecule may have an important role in leukocyte-EC interactions.
Tumor necrosis factor signal transduction. Cell-type-specific activation and translocation of protein kinase C.
Authors: Schütze S , Nottrott S , Pfizenmaier K , Krönke M
Published: December 2022

We have investigated the changes in protein kinase C (PKC) activity after treatment of several cell lines with TNF. Binding studies with [3H]phorbol dibutyrate (PBt2) on whole cells revealed rapid and transient activation of PKC in Jurkat, K562, and U937 cells with a maximum of phorbol ester binding at 6 min after TNF treatment. As shown by Scatchard analysis, the TNF-induced increase of [3H]PBt2 binding reflected increments of phorbol ester binding site numbers rather than greater binding affinities. Upon subfractionation of TNF-treated U937 cells a transient increase of PBt2 binding in the membrane fraction was accompanied by a long term loss of PBt2-binding in the cytosol, indicating a TNF-induced translocation of PKC from the cytosol to the cell membrane. With histone III-S as a substrate, the determination of specific PKC activity revealed similar kinetics of PKC translocation in U937 cells. TNF also induced PKC translocation in K562 and Jurkat cells. However, although TNF caused long term down-regulation of cytosolic PKC activity in U937 cells, the cytosolic PKC activity only transiently decreased in both Jurkat and K562 cells and then recovered to near basal levels. In the human nonmalignant fibroblast cell line CCD18, PKC was not activated by TNF. Our data suggest that PKC activation may play a major role in TNF signal transduction in some, but not all target cells.
Two Ig framework I epitopic specificities recognized by a rabbit antiserum and a monoclonal antibody to mouse VH chains.
Authors: Black A , Padlan E A , Givol D , Morrison S L , Kabat E A
Published: December 2022

The reactivity of 23 mouse monoclonal Ig with a rabbit polyclonal antiserum to VH of anti-alpha(1----6)dextran 19.22.1 and with a monoclonal anti-VH of anti-DNP MOPC315, when correlated with amino acid sequence, identified several residues in the first and third framework regions as being of potential importance in forming the epitope. Inhibition studies using synthetic peptides corresponding to residues 1-15 of the monoclonal Ig used to produce the poly- and monoclonal reagents provide evidence that the epitopes are predominantly, if not exclusively, specific for the N-terminal strand of the domain. Examination of known x-ray structures of mouse VH suggests that the primary difference between the two epitopes in the N-terminal strands is determined by the peptide chain structure due to Pro at position 9. Pro 9 appears essential for the epitope reactive with anti-VH MOPC315.
The binding site of human C4b-binding protein on complement C4 is localized in the alpha'-chain.
Authors: Hessing M , van 'T Veer C , Bouma B N
Published: December 2022

C4b-binding protein (C4BP) is a multimeric plasma protein, which regulates the classical pathway of the C system. C4BP functions as a cofactor to factor I in the degradation of C4b and accelerates the decay rate of the C4b2a complex. We now demonstrate that C4b contains a binding site for C4BP, which is localized on the alpha'-chain of C4b. SDS-PAGE of C C4 and C4b both under reducing and nonreducing conditions was followed by a radiolabeled C4BP ligand blotting procedure. It was demonstrated that the C4BP binding site on C4b is localized on the alpha'-chain. In addition, we found C4BP binding to the alpha-chain of C4, which suggests that the binding site for C4BP becomes available after reduction of the C4 molecule. Direct binding of C4BP to the alpha- and alpha'-chains of C4 and C4b was demonstrated in a radio-labeled C4BP binding assay with the reduced and alkylated isolated chains. mAb against the alpha'-chain of C4b were prepared, characterized, and evaluated for their ability to block the binding of 125I-C4BP to C4b. Two mAb specific for the alpha'-chain of C4b were found that completely abolished C4BP binding to intact C4b. Other mAb recognizing both the alpha- and alpha'-chain of C4 and C4b demonstrated only minor inhibitory effect on the binding of C4BP to C4b. In conclusion, we have localized the C4BP binding site on the alpha'-chain of C4b and have demonstrated that this binding can be inhibited by mAb specific for the alpha'-chain.
Kinetics of phospholipase A2, arachidonic acid, and eicosanoid appearance in mouse zymosan peritonitis.
Authors: Lundy S R , Dowling R L , Stevens T M , Kerr J S , Mackin W M , Gans K R
Published: December 2022

Intraperitoneal injection of zymosan into mice induces a peritonitis characterized by cellular influx, plasma leakage and the appearance of arachidonic acid (AA) metabolites. We report that zymosan injection also stimulates the accumulation of AA, docosahexaenoic acid, linoleic acid, and phospholipase A2 (PLA2) activity. The amount of the unsaturated fatty acids (UnFA) varies both with the zymosan dose and time. Significantly increased levels of UnFA were first detected 15 min after zymosan injection. Maximal levels of the UnFA were reached 1 to 2 h post zymosan injection (AA: 725 +/- 29 ng/mouse, docosahexaenoic acid: 296 +/- 23 ng/mouse, linoleic acid: 4489 +/- 179 ng/mouse) and declined to saline control levels by 8 h. PLA2 activity was significantly increased 5 to 15 min after zymosan injection. Maximal levels of PLA2 activity occurred 15 to 30 min after zymosan injection (31.8 +/- 9.1 nmol phospholipid/mg protein/h) and then decreased by 30% through 24 h. Neither the appearance of UnFA nor PLA2 activity correlated with cellular influx, but both were coincident with plasma exudation at 5 to 15 min after zymosan. However, maximal exudation occurred 1 to 2 h post zymosan injection similar to that seen with the UnFA but not PLA2. These latter results suggest that a significant portion of the UnFA found in the peritoneal cavity of zymosan-injected mice originates from the plasma. PLA2 activity at the early time points (5 to 15 min) may also contribute to the levels of UnFA via hydrolysis of tissue and/or cellular phospholipids.
Microbiostatic effect of murine-activated macrophages for Toxoplasma gondii. Role for synthesis of inorganic nitrogen oxides from L-arginine.
Authors: Adams L B , Hibbs J B , Taintor R R , Krahenbuhl J L
Published: December 2022

Recent studies show the importance of a single amino acid, L-arginine, as a necessary substrate for activated macrophage-mediated cytotoxic activity for tumor target cells and microbiostatic function for Cryptococcus neoformans. The present studies were carried out to determine the role of the L-arginine-dependent macrophage effector function on the microbiostatic effects of activated macrophages on the obligate intracellular protozoan, Toxoplasma gondii. A guanidino methylated derivative of L-arginine, NGmonomethyl-L-arginine (NGMMA), a competitive inhibitor of the L-arginine-dependent effector pathway, virtually abolished the normally potent microbiostatic effect of macrophages for Toxoplasma gondii after activation of the macrophages in vitro by IFN-gamma and LPS or in vivo by i.p. injection of killed Corynebacterium parvum. Addition of supplemental L-arginine to the culture medium overcame the capacity of NGMMA to block activated macrophage-mediated microbiostasis of Toxoplasma. The ability of NGMMA to inhibit the microbiostatic capacity of activated macrophages for Toxoplasma gondii correlated with almost total inhibition of synthesis of nitrite, nitrate, and L-citrulline from L-arginine. Therefore, as is the case for tumor target cells and C. neoformans, the synthesis of inorganic nitrogen oxides from a terminal guanidino nitrogen atom of L-arginine appears to be essential for murine cytotoxic activated macrophage mediated microbiostatic capacity for T. gondii.
A dominant Th epitope in influenza nucleoprotein. Analysis of the fine specificity and functional repertoire of T cells recognizing a single determinant.
Authors: Gao X M , Liew F Y , Tite J P
Published: December 2022

The sequence 260-283 of the nucleoprotein (NP) of influenza A virus is an epitope recognized by virus-immune lymph node cells from CBA (H-2k), B6 (H-2b), and B10.S (H-2s) mice. Further analysis shows that there are at least two Th epitopes within this sequence: the one close to the N-terminal (p260-273) is recognized by T cells from CBA and B6 mice while that close to the carboxyl-terminal (p270-283) is a dominant Th determinant in B10.S mice. The fine specificity of the recognition of this epitope by NP-specific T cell clones is also studied. When B10.S mice were infected intranasally or i.v. with live influenza virus, or immunized by different ways with various Ag preparations, P270-283 persistently emerged as a dominant T cell epitope. Immunization of B10.S mice with peptide p270-283 induces T cells with different in vivo functions including class II-restricted cytotoxicity, cognate help for Ag-specific antibody synthesis and delayed type hypersensitivity. This may have important implications for the understanding of the differentiation and classification of subsets of CD4+ T cells. The corresponding sequence of the NP of an equine influenza virus, A/Eq/Prague/56, which has a substitution (leucine to proline) at position 283, was not recognized by the lymph node cells from mice primed with either A/Okuda or A/Eq/Prague. However, the peptide, p270-283(E), representing this sequence induced T cell responses to both human and equine viruses. The data are discussed with respect to the development of viral vaccines.
Phagocytosis of Mycobacterium tuberculosis is mediated by human monocyte complement receptors and complement component C3.
Authors: Schlesinger L S , Bellinger-Kawahara C G , Payne N R , Horwitz M A
Published: December 2022

We have examined the receptor-ligand interactions and the method of phagocytosis of virulent Mycobacterium tuberculosis by human monocytes. mAb against complement receptors (CR) inhibit adherence and phagocytosis of M. tuberculosis in fresh nonimmune serum. A mAb against the type 1 CR (CR1) inhibits adherence of M. tuberculosis by 40 +/- 5%, and three different mAb against the type 3 CR (CR3) each inhibit adherence by 39 +/- 5% to 47 +/- 4%. A mAb against CR1 used in combination with one of the three mAb against CR3 inhibits adherence by up to 64 +/- 7%. Most strikingly, two mAb used in combination against CR3 inhibit adherence by up to 81 +/- 2%. mAb against other monocyte surface Ag do not significantly influence adherence. In like fashion, mAb against CR but not other monocyte surface Ag inhibit adherence of preopsonized M. tuberculosis in the presence of heat-inactivated serum. By electron microscopy, monocytes ingest all M. tuberculosis that adhere in the presence of nonimmune serum; mAb against CR3 markedly inhibit ingestion. In contrast to CR, the FcR and the beta-glucan-inhibitable receptor for zymosan play little or no role in mediating M. tuberculosis adherence or ingestion. Adherence of M. tuberculosis is serum-dependent, requiring greater than or equal to 2.5% serum for optimal adherence. Heat inactivation of serum markedly reduces adherence of M. tuberculosis (75.5 +/- 7%) and preopsonization of bacteria enhances adherence by 2.9 +/- 0.4-fold. Adherence is also markedly reduced in C3- or factor B-depleted serum; repletion with C3 or factor B increases adherence by 2.1 +/- 0.4-fold and 1.86 +/- 0.05-fold, respectively. Fab anti-C3 IgG markedly inhibits monocyte adherence of preopsonized M. tuberculosis (71 +/- 1%). C component C3 is fixed to M. tuberculosis by the alternative C pathway as determined by a whole bacterial cell ELISA. Human monocytes ingest M. tuberculosis by conventional phagocytosis as viewed by electron microscopy. This study demonstrates that human monocyte CR1 and CR3 mediate phagocytosis of M. tuberculosis and C component C3 in serum is acting as the major bacterium-bound ligand.
The T cell triggering molecule Tp103 is associated with dipeptidyl aminopeptidase IV activity.
Authors: Hegen M , Niedobitek G , Klein C E , Stein H , Fleischer B
Published: December 2022

Tp103 is a 103-kDa T cell activation molecule that defines an alternative activation signal for human T lymphocytes. It is absent from or present in only low amounts on resting T cells but is expressed strongly after activation. Cross-linking of Tp103 via a mAb CB.1 leads to triggering of functional activities in preactivated CD3+ T lymphocytes. By using mAb CB.1 in immunohistology we found that Tp103 is expressed in epithelial cells of various tissues, such as kidney, prostate, epidermis and on endothelia of liver, spleen, lungs, and most vessels, and in bile duct canaliculi in the liver. We found a carcinoma cell line expressing Tp103 and could precipitate a 110-kDa molecule from the surface of these cells. We considered several known molecules of similar distribution and molecular mass for identity with Tp103 and show here that Tp103 is probably identical to the proteolytic enzyme dipeptidyl aminopeptidase IV. When we purified Tp103 by affinity chromatography, typical dipeptidyl aminopeptidase IV activity copurified with Tp103. On activated T cells the enzymatic activity associated with Tp103 is expressed on the outside of the cell. We show that mAb CB.1 recognizes the same molecule as the anti-CD26 mAb anti-Ta1. The anti-Ta1 mAb was found to have T cell-activating activity too, but to differ in its requirements for triggering of T lymphocytes.
D-penicillamine-induced autoimmunity in Brown-Norway rats. Similarities with HgCl2-induced autoimmunity.
Authors: Tournade H , Pelletier L , Pasquier R , Vial M C , Mandet C , Druet P
Published: December 2022

D-penicillamine (DP) has been previously shown to induce an autoimmune disease in Brown-Norway (BN) rats, characterized by a dermatitis, by the production of antinuclear antibodies, by the formation fo circulating immune complexes, and by linear IgG deposits along the glomerular basement membrane. These manifestations are quite similar to those observed in mercuric chloride (HgCl2)-induced autoimmunity. The mechanism of the latter disease has been recently partly elucidated. The aim of this study was to compare DP and HgCl2-induced autoimmunity in BN rats and to compare the mechanisms involved in both situations. A transient increase in the number of spleen cells, affecting B cells and CD4+ T cells, and an increase in serum IgE concentration, previously reported in HgCl2-induced autoimmunity, were observed during DP treatment. Autoreactive anti-class II T cells able to proliferate not only in the presence of autologous B cells but also in the presence of syngeneic normal B cells were found in DP-treated BN rats. Spontaneous regulation occurred, associated with the disappearance of autoreactive T cells. Suppressor CD8+ T cells were not involved in this phenomenon. Mechanisms involved in both the induction and the regulation of DP-induced autoimmunity seem to be quite similar to those reported in HgCl2-induced autoimmunity.
Tumor necrosis factor-alpha production by astrocytes. Induction by lipopolysaccharide, IFN-gamma, and IL-1 beta.
Authors: Chung I Y , Benveniste E N
Published: December 2022

Astrocytes have the capacity to secrete or respond to a variety of cytokines including IL-1, IL-6, IL-3, and TNF-alpha. In this study, we have examined the capacity of astrocytes to secrete TNF-alpha in response to a variety of biologic stimuli, particularly cytokines such as IL-1 and IFN-gamma, which are known to be present in the central nervous system during neurologic diseases associated with inflammation. Rat astrocytes do not constitutively produce TNF-alpha, but have the ability to secrete TNF-alpha in response to LPS, and can be primed by IFN-gamma to respond to a suboptimal dose of LPS. IFN-gamma and IL-1 beta alone do not induce TNF-alpha production, however, the combined treatment of IFN-gamma and IL-1 beta results in a striking synergistic effect on astrocyte TNF-alpha production. Astrocyte TNF-alpha protein production induced by a combined treatment of either IFN-gamma/LPS or IFN-gamma/IL-1 beta occurs in a dose- and time-dependent manner, and appears to require a "priming signal" initiated by IFN-gamma, which then renders the astrocyte responsive to either a suboptimal dose of LPS or IL-1 beta. Astrocyte TNF-alpha production by IFN-gamma/LPS stimulation can be inhibited by the addition of anti-rat IFN-gamma antibody, whereas IFN-gamma/IL-1-induced TNF-alpha production is inhibited by antibody to either IFN-gamma or IL-1 beta. Polyclonal antisera reactive with mouse macrophage-derived TNF-alpha neutralized the cytotoxicity of IFN-gamma/LPS and IFN-gamma/IL-1 beta-induced astrocyte TNF-alpha, demonstrating similarities between these two sources of TNF-alpha. We propose that astrocyte-produced TNF-alpha may have a pivotal role in augmenting intracerebral immune responses and inflammatory demyelination due to its diverse functional effects on glial cells such as oligodendrocytes and astrocytes themselves.
Cytokine receptors and B cell functions. I. Recombinant soluble receptors specifically inhibit IL-1- and IL-4-induced B cell activities in vitro.
Authors: Maliszewski C R , Sato T A , Vanden Bos T , Waugh S , Dower S K , Slack J , Beckmann M P , Grabstein K H
Published: December 2022

IL-1 and IL-4 are important mediators of B cell growth and differentiation. The cell-surface receptors for these cytokines have recently been cloned and recombinant soluble receptors have been produced that bind their respective ligand. The ability of soluble forms of the murine IL-1R (sIL-1R) and IL-4R (sIL-4R) to inhibit B cell functions in vitro was examined. Proliferation of B cells treated with anti-Ig plus IL-1 or IL-4 was inhibited by the appropriate soluble receptor. sIL-4R also inhibited IL-4-dependent B cell differentiation as measured by: induction of IgG1 and IgE secretion by LPS blasts, down-regulation of IgG3 secretion by LPS blasts, increased Ia expression, and increased Fc epsilon R (CD23) expression. The inhibitory effects of the soluble receptors were found to be highly specific in that sIL-4R had no effect on IL-1-induced B cell activity and sIL-1R had no effect on IL-4 activity, further demonstrating the existence of two independent pathways of B cell activation directed by IL-1 and IL-4.
IL-4 decreases Fc gamma R membrane expression and Fc gamma R-mediated cytotoxic activity of human monocytes.
Authors: te Velde A A , Huijbens R J , de Vries J E , Figdor C G
Published: December 2022

Monocytes can express three classes of FcR for IgG: Fc gamma RI, Fc gamma RII, and Fc gamma RIII (CD64, CD32, and CD16, respectively) of which the Fc gamma RIII is expressed after prolonged culture. Fc gamma R expression is regulated by IFN-gamma. Because IFN-gamma and IL-4 have antagonistic effects on the expression of the FcR for IgE on human monocytes, we studied the effect of IL-4 on Fc gamma R expression and function. We show that IL-4 down-regulates Fc gamma RI, Fc gamma RII, and Fc gamma RIII expression of cultured monocytes and inhibits IFN-gamma enhanced Fc gamma RI expression. Exposure of monocytes to IL-4 for 40 h resulted in a dose-dependent decrease of the expression of all three Fc gamma R that persisted throughout the whole culture period (7 days). Anti-IL-4 antibodies completely reversed the IL-4 effect. In addition the impaired Fc gamma R expression correlated directly with reduced Fc gamma R-mediated function because monocytes cultured in the presence of IL-4 have a reduced capacity to lyse human E opsonized with human IgG anti-D or mouse antiglycophorin A antibodies. These observations, together with the previous finding that IL-4 induces Fc epsilon RIIb expression on monocytes, indicate that IL-4 and IFN-gamma may control the Fc gamma R-mediated immune response by differentially regulating Fc gamma R expression.
IL-4 increases human endothelial cell adhesiveness for T cells but not for neutrophils.
Authors: Thornhill M H , Kyan-Aung U , Haskard D O
Published: December 2022

The adhesion of leukocytes to vascular endothelium is the first step in their passage from the blood into inflammatory tissues. By modulating endothelial cell (EC) adhesiveness for leukocytes, cytokines may regulate leukocyte accumulation and hence the nature and progression of inflammatory responses. We have found that the T cell cytokine IL-4 increases the adhesion of T cells, but not neutrophils, to human umbilical vein EC monolayers. The increase in T cell adhesion induced by IL-4 was dose dependent (ED50 = 5 U/ml) and peaked around 33 U/ml. No increase in adhesion of neutrophils was observed at concentrations of IL-4 up to 1000 U/ml. The kinetic of the increase in T cell adhesion exhibited a steady rise peaking between 18 and 24 h before returning to basal levels by 72 h. The IL-4 specificity of the effect was confirmed by the ability of neutralizing anti-IL-4, but not anti-TNF, antibodies to abolish the effect. The increase in T cell-EC adhesion was due to an effect of IL-4 on EC inasmuch as preincubation of the T cells with IL-4 did not increase T cell binding. Furthermore, preincubation of A549 epithelial cell line monolayers with IL-4 caused no increase in T cell binding whereas A549 cells and EC showed a similarly enhanced adhesiveness for T cells after preincubation with IL-1, TNF, or IFN-gamma. EC treated with IL-4 retained their increased adhesiveness for T cells after light fixation, suggesting that IL-4 up-regulates binding by increasing the expression or accessibility of EC surface receptors for lymphocytes. Although antibodies to intercellular adhesion molecule-1 (CD54) and the beta-chain (CD18) of lymphocyte function-associated Ag-1 (CD11a/CD18) partially inhibited T cell adhesion to unstimulated EC, they did not affect the increase in adhesion due to IL-4 stimulation, indicating that the increased binding resulted from the generation of an alternative binding receptor(s) on the EC membrane. These findings suggest that IL-4 may play a role in the selective recruitment of T cells into sites of immune-mediated chronic inflammation.
Murine eosinophils and IL-1: alpha IL-1 mRNA detection by in situ hybridization. Production and release of IL-1 from peritoneal eosinophils.
Authors: Del Pozo V , De Andres B , Martin E , Maruri N , Zubeldia J M , Palomino P , Lahoz C
Published: December 2022

The presence of IL-1 mRNA in eosinophils from mice infected with larvae of the parasite Mesocestoides corti was investigated by in situ hybridization technique. S35 labeled cDNA probe for alpha IL-1, hybridized with mRNA in murine eosinophils and macrophages. After 6 h of LPS stimulation eosinophils were able to express mRNA in their cytoplasm. This expression was highly increased by the addition of indomethacine. The IL-1 mRNA expression in murine macrophages was higher than in eosinophils in LPS-stimulated cells. This difference was statistically significant, p less than 0.001. To test if eosinophils may produce and release IL-1 in the culture medium, we isolated these cells in a Percoll gradient. Cell preparations with a purity exceeding 94% were cultured with various stimuli and their supernatants were tested for IL-1 activity. Eosinophils produced 169.65 +/- 73 U/ml when stimulated with LPS (n = 14). A dose-dependent response was obtained when the eosinophils were in the presence of the calcium ionophore A23187. Controls were performed to rule out the contribution of the contaminating population on the thymocyte proliferating activity. They were also used to detect other possible causes of interference in the assay, such as leukotrienes or TNF. IL-1 in supernatants was also detected using a conversion assay such as EL-4 thymoma cells. IL-1 activity was first detected in culture supernatants 18 h later, maximal production being in the first 24 h. In accordance with our hybridization results, an increase in IL-1 activity was obtained when eosinophils were stimulated with LPS and treated with indomethacine. The factor had a molecular mass between 16 to 20 kDa that corresponded to the described for murine IL-1. Inasmuch as IL-1 is an important mediator of inflammatory reactions this IL may enhance the proinflammatory action of eosinophils.
Immunoregulatory functions of paf-acether. III. Down-regulation of CD4+ T cells high-affinity IL-2 receptor expression.
Authors: Dulioust A , Duprez V , Pitton C , Salem P , Hemar A , Benveniste J , Thomas Y
Published: December 2022

In the present report, we further explored the mechanisms by which 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine (paf-acether), a phospholipid mediator of inflammation inhibited PHA-induced CD4+ cell proliferation. Evidence was obtained that CD4+ cells stimulated with either PHA or immobilized OKT3 in the presence of paf at concentrations that block CD4+ cell proliferation, exhibited a marked decrease in high affinity IL-2R expression. Importantly, paf did not prevent the binding of IL-2 to its receptor. Scatchard analysis of the binding data indicated that paf caused more than 50% decrease in the number of IL-2 high affinity sites per cell, whereas the receptor ligand affinity remained essentially constant. Moreover, the down-regulation of high affinity IL-2R was also accompanied by a loss of IL-2-dependent proliferative capacity. Together these data suggest that decreased expression of high affinity IL-2R may contribute to the diminished proliferative activity observed in CD4+ cells stimulated with PHA or immobilized OKT3 in the presence of paf. They further emphasize the potential role of lipid proinflammatory mediators such as paf in the regulation of T cell activation.
The mapping of an antibody-binding region on the Mycobacterium tuberculosis 19 kilodalton antigen.
Authors: Ashbridge K R , Prestidge R L , Booth R J , Watson J D
Published: December 2022

To localize the epitopes of four independently derived murine mAb IT-10, IT-12, IT-16, and IT-19 on the 19-kDa Ag protein of Mycobacterium tuberculosis, expression plasmids were constructed containing deletions of the gene encoding the 19-kDa protein. Reaction of the 4 mAb with Western blots of the truncated recombinant proteins revealed two epitope specificities in the recognition of the 19-kDa protein. IT-10 was found to be dependent only on the presence of amino acids surrounding the first cysteine residue, whereas IT-12, IT-16, and IT-19 all required the presence of both the first and third cysteine residues. These two cysteine residues are separated by 135 amino acids, and are considered to be brought together by tertiary folding of the protein to form an assembled epitope for IT-12, IT-16, and IT-19. These three mAb demonstrated differing sensitivities to the modification of reduced 19-kDa protein using iodoacetamide: a treatment that should have prevented the reformation of disulfide bonds within the protein. This result suggests that, although IT-12, IT-16, and IT-19 appear to be specific for the same epitope, there are probably fine-specificity differences in this recognition. IT-10 was not sensitive to the absence of disulfide bonds within the 19-kDa protein, suggesting that the epitope is not conformationally sensitive, and is likely to be linear in nature.