bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of loss and change of specificity resulting from random mutagenesis of an antibody VH region.
Authors: Casson L P , Manser T 
Published: December 2022

Abstract
Most data available from in vivo sources regarding the impact of somatic hypermutation on Ab V region structure and function are heavily biased due to the influence of clonal selection. In an effort to address this issue directly, we "randomly" introduced point mutations throughout the length of the VH region of an anti-p-azophenylarsonate (Ars) Ab expressed as an Fab in the phage display format. This was accomplished by means of an error-prone PCR with two protocols, which resulted in two mutant libraries. The nature of the nucleotide substitutions obtained from each protocol differed from each other and resulted in different frequencies of phage clones that did not appear to contain Fab on their surfaces. However, the majority of mutants in both libraries lacked detectable Fab expression. Screening of the library containing the most expressed Fabs for those that had gained affinity for structurally related haptens yielded two independent mutants that lacked detectable affinity for Ars and had high affinity for p-azophenylsulfonate. These mutants both contained amino acid substitutions from Asn to Ser or Thr at VH CDR1 position 35, a putative Ars contact residue. In this paper, we discuss the significance of these data with regard to the frequencies of V region loss of function, gain of increased affinity, and gain of altered specificity that result from somatic hypermutation in vivo.
CD8 T cell clones inhibit antitumor T cell function by secreting IL-10.
Authors: Rohrer J W , Coggin J H 
Published: December 2022

Abstract
We have reported that in irradiated, long-term surviving RFM strain of mice there is enhanced kinetics of tumor development upon challenge with RFM lymphoma cells. We reported that we cloned splenic oncofetal (OFA)-specific, noncytotoxic CD8+ T cells from such mice. These noncytotoxic CD8+ T cell clones secrete a factor upon Ag stimulation that inhibits the ability of OFA-specific RFM cytotoxic T (TC) cell clones from killing 5T RFM lymphoma cells in vitro. These supernatants do not inhibit the tumor cell-induced proliferation of the TC cell clones however. We report here that OFA-stimulated, RFM-noncytotoxic CD8 T cell clone culture supernatants also inhibit IFN-gamma-secretion by stimulated CD4 and CD8 RFM anti-OFA effector T cell clones in a dose-dependent manner. The inhibitor in those culture supernatants acts in neither an Ag-specific nor MHC-restricted manner. We find that the culture supernatants of OFA-stimulated, noncytotoxic CD8 T cell clones contain IL-10, while those from OFA-stimulated, RFM OFA-specific TC cell clones do not. We show that monoclonal anti-IL-10 Ab specifically blocks the inhibition of cytotoxic activity and IFN-gamma secretion by OFA-specific CD8 and CD4 effector T cell clones in a dose-dependent manner in vitro. Incorporation of anti-IL-10 Ab into the cytotoxicity assays of the OFA-specific, noncytotoxic CD8+ T cell clones against 5T tumor cells restores their cytotoxic activity. This may suggest that one way of inducing anergic T cells is by induction of IL-10 secretion.
Modulation of rat B cell differentiation in vivo by the administration of an anti-mu monoclonal antibody.
Authors: Soares M , Havaux X , Nisol F , Bazin H , Latinne D 
Published: December 2022

Abstract
We have previously described that the administration of an anti-mu mAb to adult rats results in the total depletion of circulating IgM. In the present study we analyzed the cellular mechanisms involved in the depletion of circulating IgM by the administration of an anti-mu mAb to adult rats. Administration of an anti-mu mAb to adult rats led to the cross-linking and internalization of membrane IgM (mIgM) but not mIgD on the surface of B cells. This correlated with the depletion in spleen and bone marrow of immature and short-lived Thy-1+ CD45RB+ B cells and with the specific depletion of the number of IgM but not IgA-, IgG1-, IgG2a-, and IgG2b-secreting cells in the spleen, which paralleled the depletion of circulating IgM but not IgA, IgG1, IgG2a, and IgG2b. In contrast to the other IgG subclasses, IgG2c-secreting cells as well as circulating IgG2c were increased by 10-fold in anti-mu-treated rats as compared with controls. Finally, anti-mu-treated rats showed an inhibition in the generation of primary thymus-dependent as well as thymus-independent Ab responses as compared with controls. In conclusion, the data presented suggests that anti-mu administration in adult rats results in the early arrest of B cell differentiation in the bone marrow, which causes the down-regulation of IgM production. Furthermore, anti-mu mAb administration directly or indirectly activates a particular subset of mature B cells, which differentiates into IgG2c-secreting cells.
Inhibitory effects of sulfasalazine and its metabolites on histamine release and TNF-alpha production by mast cells.
Authors: Bissonnette E Y , Enciso J A , Befus A D 
Published: December 2022

Abstract
Sulfasalazine is an effective treatment in some inflammatory diseases that exhibit mast cell (MC) hyperplasia. However, its effect on MC has been incompletely studied. We have established that sulfasalazine inhibits the release of histamine and TNF-alpha from MC. Sulfasalazine and its metabolites, 5-aminosalicylic acid (5-ASA) and to a lesser extent sulfapyridine, inhibited Ag-stimulated histamine release from rat peritoneal MC in a concentration-dependent manner with a 50% inhibitory concentration of 6 x 10(6)M, 8 x 10(-6)M, and 3 x 10(-4)M, respectively. Similar results were observed with sulfapyridine and 5-ASA on Ag-stimulated histamine release of another population of MC, namely rat intestinal mucosal MC, but sulfasalazine was markedly less potent than its metabolites. Interestingly, sulfasalazine and sulfapyridine, but not 5-ASA, inhibited Ag-stimulated TNF-alpha released by MC. Similar results were observed with MC-mediated cytotoxic activity in which sulfasalazine and sulfapyridine, but nor 5-ASA, inhibited MC TNF-alpha-dependent cytotoxicity in a concentration-dependent manner. The addition of sulfasalazine to MC, up to 12 h after the cytotoxic assay (16 h) had started, significantly inhibited cytotoxic activity, suggesting that sulfasalazine inhibited the cytotoxic mediator, TNF-alpha. Indeed, affinity studies demonstrated that sulfasalazine binds TNF-alpha. Furthermore, the inhibition of MC cytotoxicity by sulfasalazine appeared to require new protein synthesis. Pretreatment of MC with sulfasalazine also inhibited the release of TNF-alpha and reduced the levels of TNF-alpha mRNA. Thus, sulfasalazine inhibits MC-mediated, TNF-alpha-dependent cytotoxicity by multiple mechanisms: competitive inhibition of soluble TNF-alpha, reduction of levels of TNF-alpha mRNA, and inhibition of TNF-alpha release.
In vivo cytokine production in murine listeriosis. Evidence for immunoregulation by gamma delta+ T cells.
Authors: Hsieh B , Schrenzel M D , Mulvania T , Lepper H D , DiMolfetto-Landon L , Ferrick D A 
Published: December 2022

Abstract
Differential cytokine production by gamma delta+ T cells influences Th1 and Th2 responses. Here, we describe the in vivo kinetics of peritoneal and splenic gamma delta+, CD4+, and CD8+ T cell cytokine responses during primary and secondary Listeria infections. The data show differences in the kinetics of IFN-gamma-producing alpha beta+ splenocytes consistent with immunologic memory. Most noteworthy, however, was the elevated production of IL-10 by splenic gamma delta+ T cells in the red pulp and marginal zones that coincided with maximal IFN-gamma production and with a decrease in inflammation and tissue damage. This result implies a role for gamma delta+ T cells in the control of Th1 responses.
A common epitope on platelet integrin alpha IIb beta 3 (glycoprotein IIbIIIa; CD41b/CD61) and alpha M beta 2 (Mac-1; CDIIb/CD18) detected by a monoclonal antibody.
Authors: De Nichilo M O , Shafren D R , Carter W M , Berndt M C , Burns G F , Boyd A W 
Published: December 2022

Abstract
Evidence is presented that the mAb 25E11, directed against the platelet integrin alpha IIb beta 3 (glycoprotein IIbIIIa;CD41b/CD61) also binds the distinct myeloid cell integrin alpha M beta 2 (Mac-1;CDIIb/CD18). The Ab is shown to identify only the alpha IIb beta 3 integrin complex and not the individual subunits in crossed Ab immunoelectrophoresis of platelet lysate. From cultured human macrophages, sequential immunoprecipitation of labeled glycoproteins indicated that 25E11 also bound the Mac-1 (CD11b/CD18) complex. This was confirmed using COS-7 and WOP cells doubly transfected with alpha M (CD11b) and beta 2 (CD18) or with alpha L (CD11a) and beta 2 when it was found that the Ab bound only the alpha M beta 2 transfectants. Studies with these cells and the RC2A myeloid cell line stimulated with tetradecanoyl phorbol acetate or FMLP indicated that the 25E11 epitope on Mac-1 did not depend on cell activation for its expression. The rationale for this cross-reactivity is not known, but since the 25E11 Ab inhibits the function of both platelets and myeloid cells, it is likely that this shared epitope is important to integrin function. Given the expression of this epitope on IIbIIIa and Mac-1, the dominant integrins of platelets and granulocyte/macrophage cells, but not on other integrins, a role of this epitope in the early events of inflammation is suggested.
Oncostatin M inhibits IL-1-induced expression of IL-8 and granulocyte-macrophage colony-stimulating factor by synovial and lung fibroblasts.
Authors: Richards C D , Langdon C , Botelho F , Brown T J , Agro A 
Published: December 2022

Abstract
The role of oncostatin M (OM) in modulating production of cytokines by connective tissue cells is largely unexplored. We have examined the effects of stimulating fibroblast cultures derived from human synovium and from normal lung with OM alone or in combination with IL-1, IL-1 alpha (or IL-1 beta) at 1 or 5 ng/ml, stimulated production of high levels of granulocyte-macrophage CSF (GM-CSF), IL-8, and IL-6 protein. At various concentrations (0.1-50 ng/ml), OM alone failed to significantly enhance protein or mRNA levels of GM-CSF, IL-8, IL-6, or G-CSF after 18 h of stimulation. When combined with IL-1 alpha or -beta, OM caused a dose-dependent inhibition of the IL-1-induced level of IL-8 and GM-CSF protein and mRNA expression, whereas IL-6 production was simultaneously enhanced. In contrast, when IL-6 or leukemia inhibitory factor (two other cytokines that share gp130 receptor components with OM) were used in a similar fashion in combination with IL-1 alpha, neither cytokine consistently altered the IL-1-induced levels of IL-8, GM-CSF, or IL-6. In addition, only OM and not IL-6 or leukemia inhibitory factor was able to induce STAT-1 nuclear factor binding to DNA in stimulated fibroblast extracts as measured by electrophoretic mobility shift assay. These results suggest that OM can significantly alter cytokine profiles of stimulated fibroblasts and may play a unique role in modulating cytokine production by these cells at sites of inflammation.
Peroxynitrite-mediated DNA strand breakage activates poly-adenosine diphosphate ribosyl synthetase and causes cellular energy depletion in macrophages stimulated with bacterial lipopolysaccharide.
Authors: Zingarelli B , O'Connor M , Wong H , Salzman A L , Szabó C 
Published: December 2022

Abstract
The inducible isoform of nitric oxide (NO) synthase produces large quantities of NO, a cytotoxic free radical. Recent studies show that treatment with exogenous NO produces DNA strand breaks, activating the nuclear repair enzyme poly(ADP)ribosyltransferase (PARS), which results in ADP ribosylation, NAD+ consumption, and exhaustion of intracellular energy stores. Here we have characterized the cytotoxic effect of endogenous NO and peroxynitrite, a reactive oxidant formed from NO and superoxide. Immunostimulation of J774.2 macrophages with endotoxin resulted in the generation of superoxide (within 1 h) and NO (after 8 h). NO production paralleled an increase in peroxynitrite formation and DNA strand breakage, and a decrease in intracellular NAD+ content and mitochondrial respiration. Inhibition of NO synthase by NG-methyl-L-arginine or S-methyl-isothiourea or inhibition of PARS activity by 3-aminobenzamide or nicotinamide prevented the decrease in mitochondrial respiration and the depletion of NAD+. A similar pattern of free radical formation and cytotoxicity was observed in peritoneal macrophages from endotoxemic rats (formation of NO, superoxide, peroxynitrite, and DNA strand breaks). In vivo treatment with 3-aminobenzamide preserved mitochondrial respiration, NAD+, and ATP. Our data suggest that inflammatory cell injury involved DNA strand breakage and PARS, triggering an energy-consuming, futile repair cycle leading to cellular energy depletion. The active species responsible for the development of DNA strand breaks is peroxynitrite, rather than NO, since exogenous peroxynitrite, but not NO, induces DNA strand breaks. Inhibition of PARS may improve cellular energy homeostasis in patho-physiologic conditions associated with peroxynitrite generation.
Analysis of initial attachment of B cells to endothelial cells under flow conditions.
Authors: Yago T , Tsukuda M , Tajima H , Nishi T , Kurata-Miura K , Ohkubo J , Minami M 
Published: December 2022

Abstract
This study examined the adhesive interactions of peripheral blood B cells with TNF-alpha-activated endothelial monolayers, and analyzed the roles of E-selectin, P-selectin, or VCAM-1 molecules expressed on activated HUVEC. B cell interaction occurred on activated HUVEC, but not on resting HUVEC under flow conditions. The majority of peripheral blood B cells expressed P-selectin glycoprotein ligand-1 and alpha4 integrin. However, the expression of cutaneous lymphocyte Ag on B cells was low. Under flow conditions, B cells could bind to P-selectin-coated tubes and VCAM-1-transfected Chinese hamster ovary cells. In contrast, B cells could not bind to E-selectin-coated tubes. Adhesion activity of B cells to P-selectin-coated tubes was weaker than that of T cells. Furthermore, adhesion activity of B cells to VCAM-1-transfected Chinese hamster ovary cells was similar to that of T cells. Treatment of activated HUVEC with anti-VCAM-1 mAb reduced interaction of B cells under flow conditions. However, the treatment of activated HUVEC with anti-P-selectin mAb did not reduce interaction. These data indicated that the interaction of VCAM-1 with alpha4 integrin plays a major role in an initial attachment of B cells to endothelial monolayers under flow conditions.
The hinge as a spacer contributes to covalent assembly and is required for function of IgG.
Authors: Coloma M J , Trinh K R , Wims L A , Morrison S L 
Published: December 2022

Abstract
Chimeric IgG3 lacking a genetic hinge but with Cys residues in CH2 between position 231 and 232 (IgG3 deltaH+Cys) and position 279 (IgG3 deltaH+2Cys) produced by site-directed mutagenesis have been found to be deficient in their intermolecular assembly. Although some H2L2 molecules are formed, significant quantities of assembly intermediates, in particular HL, are found in the secretions. Both IgG3 deltaH+Cys and IgG3 deltaH+2Cys were greatly reduced in their ability to bind Fc gammaRI. They also failed to bind C1q and activate the complement cascade. Addition of the tailpiece from IgM (microtp) to IgG3 deltaH+Cys (yielding IgG3 deltaH+Cys microtp) failed to lead to efficient oligomerization. IgG3 deltaH+Cys microtp failed to bind Fc gammaRII. However, at high concentrations it was able to bind C1q and effect complement-dependent cytolysis. It consumed complement in the absence of added Ag, indicating that removing the flexible hinge was not sufficient to yield polymeric IgG that resembled IgM in its dependence on added Ag for complement activation.
The IL-13 receptor structure differs on various cell types and may share more than one component with IL-4 receptor.
Authors: Obiri N I , Leland P , Murata T , Debinski W , Puri R K 
Published: December 2022

Abstract
We have reported on the expression and characteristics of IL-13R and have demonstrated that IL-13 competes for IL-4 binding while IL-4 did not compete for the IL-13 binding on some cell types. Based on these observations, and the size of IL-13 and IL-4 cross-linked proteins, we concluded that the receptor for IL-13 is complex and shares a subunit with the receptor for IL-4. To explore the complexity of the IL-13R, a wide variety of cell types was examined for IL-13 and IL-4 binding. We report in this work that IL-4 does not always bind well to cells that bind IL-13, but the reverse is also true. We also found that IL-4 can compete more effectively for IL-13 binding than IL-13 itself. Cross-linking studies support these observations and demonstrate that 125I-labeled IL-13 bound exclusively to a single 65- to 70-kDa protein in MA-RCC and U251 cells, while in TF-1 cells it cross-linked to two membrane proteins of 65 to 70 kDa and 140 kDa. Furthermore, by using a chimeric protein composed of IL-13 and Pseudomonas exotoxin A, we observed that IL-4 neutralized the cytotoxicity of the IL-13 toxin on COS-7 cells by blocking a common form of the two cytokine receptors. We propose that the 65- to 70-kDa form of the IL-13R is the predominant common component shared between IL-13 and IL-4R. However, the primary IL-4 binding (p140) protein also participates in the formation of the IL-13R complex in some cell types. In addition, the gamma(c) or another interactive subunit may influence IL-13 binding to its receptor complex. Thus, we propose that there are at least four forms of IL-13R.
In vivo engineering of a cellular immune response by coadministration of IL-12 expression vector with a DNA immunogen.
Authors: Kim J J , Ayyavoo V , Bagarazzi M L , Chattergoon M A , Dang K , Wang B , Boyer J D , Weiner D B 
Published: December 2022

Abstract
Recent studies support the importance of investigating a DNA vaccination approach for the immunologic control of HIV-1. In this regard, it may be important to specifically engineer immune responses in order to improve on first generation vaccine attempts. Especially for HIV, induction of cell-mediated immunity may be an important feature for any candidate vaccine. In an attempt to engineer in vivo the enhancement of cellular immune response and to direct Ag-dependent immune response from Th2 to Th1 type, we investigated the role of codelivery of genes for IL-12 and granulocyte-macrophage-CSF along with DNA vaccine formulations for HIV-1 Ag. We found that codelivery of IL-12 expression cassettes with DNA vaccines for HIV-1 in mice resulted in splenomegaly as well as a shift in the specific immune responses induced. The codelivery of IL-12 genes resulted in the reduction of specific Ab response, while the coinjection of granulocyte-macrophage-CSF genes resulted in the enhancement of specific Ab response. In addition, we observed a significant Ag-specific stimulation of T cells with codelivery of both cytokines. Most importantly, we observed a dramatic increase in specific CTL response from the group coimmunized with the HIV-1 DNA vaccine and IL-12 genes. This work demonstrates the power of DNA delivery in vivo for both the production of a new generation of more effective and targeted vaccines or immunotherapies as well as an analytic tool for the molecular dissection of the mechanisms of immune function.
Intranasal immunization with CTL epitope peptides from HIV-1 or ovalbumin and the mucosal adjuvant cholera toxin induces peptide-specific CTLs and protection against tumor development in vivo.
Authors: Porgador A , Staats H F , Faiola B , Gilboa E , Palker T J 
Published: December 2022

Abstract
To evaluate the ability of mucosal immunization protocols using peptide immunogens to induce CTL responses, BALB/c and C57BL/6 mice were immunized intranasally (i.n.) with peptides corresponding to a known CTL epitope in HIV-1 glycoprotein 120 or OVA, respectively, and the mucosal adjuvant cholera toxin (CT). Intranasal immunization of BALB/c mice with a 10- or 15-amino acid peptide corresponding to a CTL determinant in HIV-1 glycoprotein 120 and CT induced peptide-specific CTLs in spleen cells that persisted through 35 days after the last immunization. Intranasal immunization of C57BL/6 mice with the octameric OVA peptide and CT produced similar results with detectable peptide-specific CTL in both the cervical lymph node and spleen. To test whether CTL induced by i.n. immunization with OVA peptide and CT were functional in vivo, groups of C57BL/6 mice were injected with E.G7-OVA tumor cells that express the OVA protein and monitored for tumor growth. Animals immunized i.n. with OVA and CT were protected against tumor development as efficiently as animals immunized by the potent CTL induction protocol of i.v. injection with OVA-pulsed dendritic cells. Intranasal immunization with peptides corresponding to known CTL epitopes and CT provides a noninvasive route of immunization for the induction of CTL responses in vivo.
The human complement C1 complex has a picomolar dissociation constant at room temperature.
Authors: Tseng Y , Zavodszky P , Schumaker V N 
Published: December 2022

Abstract
Periodic sampling of serum or reconstituted C1 initially diluted 1/2000 and 1/4000 (that is, to 0.1 and 0.05 nM) into a recombinant C1s-containing solution showed a gradual decline of hemolytic activity until equilibrium was approached, consistent with a simple dissociation, reassociation equilibrium, presumably C1 &lt;--&gt; C1q + C1r2C1s2. The presence of excess (5 nM) recombinant C1s minimized further dissociation of the C1r2C1s2, allowing the first step to be studied independently of the dissociation of C1r2C1s2 &lt;--&gt; C1r2 + 2 C1s. Reassociation experiments were also performed, starting with the dissociated C1 diluted to the same concentrations and following the regain of hemolytic activity to approximately the same values, showing that the same equilibrium had been achieved from both directions. Analysis of the kinetic data yielded forward and reverse rate constants and the equilibrium constant, for which values of approximately 72 and 3 pM were estimated at 0 and 23 degrees C, respectively. The effects of temperature, ionic strength, Ca2+ ion concentration, and activation of the zymogen on the equilibrium constants were explored; extreme sensitivity to temperature, ionic strength, and activation were found. At 23 and 30 degrees C, slow activation of C1 was also evident. Highly purified, reconstituted C1 yielded approximately the same values for the kinetic and equilibrium parameters as serum C1, suggesting that the structure of the reconstituted complex was similar to or identical with that of the serum C1 complex.