bluuebunny/crossref_metadata_2025_split huggingface dataset:
Only the initial binding of cationic immune complexes to glomerular anionic sites is mediated by charge-charge interactions.
Authors: Gauthier V J , Mannik M 
Published: December 2022

Abstract
The role of charge-charge interactions between cationic immune complexes and the anionic sites on the glomerular basement membrane was examined. For this purpose, soluble immune complexes at fivefold antigen excess were prepared with human serum albumin and cationized rabbit antibodies to this protein. When unrelated cationic proteins, protamine sulfate or cationized rabbit serum albumin, were given 1 min before the cationized immune complexes, glomerular immune deposits did not form. Cationic immune complexes allowed to deposit in glomeruli could readily be displaced by protamine sulfate or cationized rabbit serum albumin injected 1 min after the immune complexes. If the same cationic molecules were injected 1 hr after the immune complexes, the complexes could not be displaced from glomeruli. In contrast, cationic complexes that were deposited in glomeruli in the presence of a very high degree of antigen excess in circulation to prevent their condensation into larger complexes in glomeruli were readily displaced at 1 min and 1 hr with protamine sulfate or with cationized rabbit serum albumin. On the basis of these results, we concluded that the initial binding of cationic immune complexes to glomeruli occurs by charge-charge interactions. Once the immune complexes in glomeruli condense to larger deposits, forces other than charge-charge interactions are responsible for their retention in glomeruli.
A 44 kilodalton cell surface homodimer regulates interleukin 2 production by activated human T lymphocytes.
Authors: Martin P J , Ledbetter J A , Morishita Y , June C H , Beatty P G , Hansen J A 
Published: December 2022

Abstract
We previously described a cell surface antigen, termed Tp44, detected by monoclonal antibody 9.3 on approximately 80% of mature human T lymphocytes. Analysis by SDS-polyacrylamide gel electrophoresis and isoelectric focusing demonstrated that this antigen consists of two identical 44 kilodalton glycopeptides that form a disulfide-linked homodimer. Competitive binding experiments showed that antibody 9.3 and an anti-CD3 antibody (64.1) recognize distinct antigenic determinants; furthermore, the binding of antibody 9.3 was unaffected by prior modulation of CD3. Thus, Tp44 has no detectable cell surface association with CD3. By itself, antibody 9.3 had no detectable effect on either IL 2 receptor expression or IL 2 release, and did not cause T cell proliferation even when monocytes were present and exogenous IL 2 was provided, indicating that binding of antibody 9.3 does not provide a primary signal for T cell activation. However, the proliferative responses of T lymphocytes activated by phytohemagglutinin, concanavalin A, or an anti-CD3 monoclonal antibody were strikingly enhanced in the presence of antibody 9.3, an effect associated with increased IL 2 receptor expression and increased IL 2 secretion. Antibody 9.3 enabled anti-CD3-Sepharose-activated T cells and anti-CD3 antibody-activated Jurkat cells to release IL 2 in the absence of monocytes. Fab fragments of antibody 9.3 had no effect on anti-CD3-induced IL 2 release by Jurkat cells, whereas F(ab')2 fragments had activity comparable to that of unmodified antibody, indicating that bivalent binding of Tp44 molecules is required for IL 2 secretion. Together, these results suggest that TP44 may function as a receptor for accessory signals in the activation of T cells.
Contra-IL 2; a suppressor lymphokine that inhibits IL 2 activity.
Authors: Maki T , Satomi S , Gotoh M , Monaco A P 
Published: December 2022

Abstract
Suppressive activity of culture supernatant of AS-9 (AS-9 CS), a T cell hybridoma line that was derived from fusion of BW5147 thymoma and splenic T cells of anti-lymphocyte serum-treated C3H mice, was analyzed. AS-9 CS inhibited allogeneic cytotoxic T lymphocyte (CTL) generation as well as T cell proliferation to alloantigens and mitogens, but failed to inhibit B cell response to lipopolysaccharide or growth of tumor and fibroblast cells. Although addition of AS-9 CS to the allogeneic sensitization culture as late as on day 2 of incubation resulted in maximal inhibiton of CTL generation, removal of AS-9 CS on day 3 of incubation abolished its inhibitory effect. Addition of purified IL 2 together with AS-9 CS to the allogeneic sensitization cultures only partially abrogated the suppression. Experiments with IL 2-dependent cytotoxic T cell line (CTLL) showed that AS-9 CS suppressed the IL 2-induced proliferation of CTLL. Preincubation of AS-9 CS with CTLL removed its inhibitory effect on CTL generation. These results indicate that AS-9 CS interferes with the mechanism of T cell activation by IL 2. On this basis, AS-9 CS was named contra-IL 2.
Epitope and functional specificity of monoclonal antibodies to mouse interferon-gamma: the synthetic peptide approach.
Authors: Russell J K , Hayes M P , Carter J M , Torres B A , Dunn B M , Russell S W , Johnson H M 
Published: December 2022

Abstract
Spleen cells from hamsters immunized with recombinant mouse interferon-gamma (IFN-gamma) were fused with mouse myeloma cells, resulting in the production of four anti-IFN-gamma monoclonal antibodies. Binding of 125I-IFN-gamma by these protein A-bound antibodies was specifically blocked by cold IFN-gamma. Binding by three of these antibodies was also blocked by a synthetic peptide corresponding to the N-terminal 1-39 amino acids of IFN-gamma, whereas a corresponding C-terminal (95-133) peptide had no effect on binding. The N-terminal specificity of these three antibodies was confirmed by their specific binding of 125I-N-terminal (1-39) peptide. One of the N-terminal specific monoclonal antibodies inhibited both antiviral and macrophage priming (for tumor cell killing) activities of IFN-gamma, whereas the other two had no effect on either biologic function. The selectivity of the inhibition of IFN-gamma function was not due to a differential ability of the N-terminal specific antibodies to bind IFN-gamma. Blocking experiments with cold IFN-gamma and N-terminal peptide suggest that the epitope specificities of the monoclonal antibodies could be determined by the conformational or topographic structure of IFN-gamma. An exact determination of the epitope specificity of the monoclonal antibody that inhibited IFN-gamma function could provide insight into the structural basis for the role of the N-terminal domain in the biologic function of IFN-gamma. Polyclonal antibodies to either the N-terminal or the C-terminal peptides also inhibited both the antiviral and the macrophage-priming activities of IFN-gamma. All of the antibodies that inhibited IFN-gamma function also blocked binding of IFN-gamma to membrane receptor on cells, whereas antibodies that did not block function also did not inhibit binding. The data suggest that both the N-terminal and the C-terminal domains of IFN-gamma play an important role in its antiviral and macrophage-priming functions, possibly in a cooperative manner.
Interferon-gamma binds to high and low affinity receptor components on murine macrophages.
Authors: Aiyer R A , Serrano L E , Jones P P 
Published: December 2022

Abstract
Interferon-gamma (IFN-gamma), a glycoprotein secreted by antigen-or mitogen-activated lymphocytes, modulates the activities of lymphocytes and macrophages. For mouse macrophages, murine IFN-gamma (MuIFN-gamma) stimulates several functions, including phagocytosis, tumoricidal activity, and the increased expression of Ia and H-2 antigens of the major histocompatibility complex. Recent reports have suggested that IFN-gamma specifically binds to cell surface receptors corresponding to a single class of binding sites with a Kd of 10(-8) to 10(-10) M. We present evidence that, on the murine macrophage cell line WEHI-3, MuIFN-gamma specifically binds to two classes of binding sites with Kd of 9.1 X 10(-11) M (500 sites/cell) and 2.7 X 10(-9) M (4400 sites/cell). The higher affinity sites most likely represent the physiologically relevant receptors that mediate at least some of the actions of MuIFN-gamma.
Endogenous association of decay-accelerating factor (DAF) with C4b and C3b on cell membranes.
Authors: Kinoshita T , Medof M E , Nussenzweig V 
Published: December 2022

Abstract
Decay-accelerating factor (DAF) is a membrane glycoprotein found on various cells that are in contact with complement. It inhibits the formation of the C3 convertases of the complement system, both the classic (C4b2a) and alternative (C3bBb) pathways. In this investigation, we used a homobifunctional cross-linking reagent to search for a DAF ligand on the surface of cells subjected to complement attack. We found that DAF forms complexes with C4b and C3b deposited on the same erythrocytes, but not with the physiologic degradation products of these complement fragments, that is, C4d or C3dg. Taken together with prior observations that DAF action is reversible, and DAF does not affect the structure of C4b or C3b, these findings suggest that DAF functions by competitively inhibiting the uptake of C2 or factor B, and preventing the assembly of the C3 convertases.
Neutrophil activation detected by monoclonal antibodies.
Authors: Tetteroo P A , Bos M J , Visser F J , von dem Borne A E 
Published: December 2022

Abstract
Monoclonal antibodies have been produced against three neutrophil-associated membrane proteins (p 90, p 170, and p 70) expressed at different maturation stages of the cells. The reactivity of the antibodies against p 90 (B13.9) and p 170 (CLB-gran 10), as measured by quantitative flow cytofluorometry, increased after stimulation of the neutrophils by the calcium ionophore A23187, by phorbol myristate acetate, or by the chemoattractant formylmethionyl-leucyl-phenylalanine in combination with cytochalasin B. This increase is regulated independently of the simultaneously increased expression of the C3bi receptor, because neutrophils of a patient deficient for the C3bi receptor showed a normal increase in membrane expression of p 90 and p 170. Neutrophil cytoplasts were not inducible to increased membrane expression, suggesting that the cytoplasts lack the internal pool of these proteins. The reactivity of the antibody against p 70 (CLB-gram 5) was not affected by activation. The antibodies B13.9 and CLB-gran 10 may be useful to detect neutrophil activation.
Substrate specificity and partial characterization of the PAF-acylhydrolase in human serum that rapidly inactivates platelet-activating factor.
Authors: Wardlow M L , Cox C P , Meng K E , Greene D E , Farr R S 
Published: December 2022

Abstract
The structure of the potent inflammatory mediator, platelet-activating factor, is 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine (AGEPC, PAF-acether). Human sera contain an acid labile factor (ALF) that is a Ca+2-independent 2-acylhydrolase-specific for AGEPC and AGEPC-like molecules. The enzyme functions by catalytically removing the sn-2 acetyl moiety from AGEPC, producing the biologically inactive sn-2 hydroxy form or 2-lyso-GEPC. Incubation of ALF with sn-2 acyl PAF analogs indicated that the enzyme hydrolyzes the sn-2 fatty acid only if the chain length is five carbons or less, the sn-1 position fatty acid length is greater than 10 carbon units, and at least one methyl group is present on the terminal amine of the choline group. The enzyme was active with either an ether or ester linkage at the sn-1 position. ALF is inactivated by heating to 65 degrees C for 30 min. It is pronase and trypsin sensitive but resistant to papain and papain with dithiothreitol. Further characteristics of human ALF indicated a broad pH range of activity with an optimum of pH 6.2 and an isoelectric point of 6.2 to 6.7. The specificity and Ca+2 independence of human ALF sets it apart from phospholipase A2. It is proposed that human ALF be called human serum PAF-acylhydrolase to distinguish it from other hydrolases currently known to exist.
Mechanism of action of glucocorticoid-induced immunoglobulin production: role of lipoxygenase metabolites of arachidonic acid.
Authors: Goodwin J S , Atluru D 
Published: December 2022

Abstract
Glucocorticoids stimulate polyclonal immunoglobulin (Ig) production in cultures of human peripheral blood lymphocytes. The mechanism of action of glucocorticoids in this system, and indeed in any physiologic system, is unknown. Because glucocorticoids stimulate the production of phospholipase A2-inhibitory glycoproteins, we investigated whether glucocorticoids stimulate polyclonal Ig production by inhibition of arachidonic acid metabolism. Nonspecific lipoxygenase/cyclooxygenase inhibitors stimulate polyclonal Ig production in a manner similar to the effect of glucocorticoids, whereas specific cyclooxygenase inhibitors actually inhibit Ig production. Two specific 5-lipoxygenase inhibitors, with little or no activity against cyclooxygenase or other lipoxygenases, also stimulate Ig production. The dose-response effect of all of these drugs on Ig production was similar to the dose response of inhibition of 5-lipoxygenase. Leukotriene B4 (LTB4) added in low concentrations (10(-10)M) on days 1, 2, and 3 of a culture eliminated the stimulatory effect of glucocorticoids or 5-lipoxygenase inhibitors, whereas LTC4, LTD4, prostaglandin E, or 5-hydroxyeicosatetraenoic acid had no effect. These results suggest that the relevant action of glucocorticoids in stimulating Ig production might be in preventing endogenous arachidonic acid metabolism, perhaps the endogenous production of LTB4.
Adoptive immunotherapy of a syngeneic murine leukemia with a tumor-specific cytotoxic T cell clone and recombinant human interleukin 2: correlation with clonal IL 2 receptor expression.
Authors: Matis L A , Shu S , Groves E S , Zinn S , Chou T , Kruisbeek A M , Rosenstein M , Rosenberg S A 
Published: December 2022

Abstract
The successful adoptive immunotherapy of the syngeneic Friend virus-induced murine leukemia FBL-3 was mediated by a proliferative MHC-restricted, tumor-specific CTL clone in combination with recombinant human IL 2. This clone was previously shown to express the L3T4-, Lyt-1+, Lyt-2+ surface phenotype. Activation of the clone for 48 hr in vitro with irradiated tumor cells induced the expression of IL 2 receptors and markedly increased clonal proliferation in response to recombinant IL 2. Intravenous injection of 2 X 10(7) 48 hr in vitro-activated cloned cells, followed by 6 days of systemic (i.p.) administration of IL 2 resulted in the complete regression of tumors and the cure of 50% of the treated mice. IL 2 alone had no effect on tumor growth, whereas the injection of nonactivated (resting) clone plus IL 2 or activated clone without IL 2 had small but insignificant effects on tumor growth and survival. These results indicated that the in vivo effector functions of cloned T cells may be markedly enhanced by the concurrent systemic administration of recombinant IL 2 and by the induction of optimal IL 2 receptor expression on the cloned T cells at the time of cell administration.
Interdependence of the radioprotective effects of human recombinant interleukin 1 alpha, tumor necrosis factor alpha, granulocyte colony-stimulating factor, and murine recombinant granulocyte-macrophage colony-stimulating factor.
Authors: Neta R , Oppenheim J J , Douches S D 
Published: December 2022

Abstract
Interleukin 1 alpha (IL-1 alpha), tumor necrosis factor alpha (TNF alpha), granulocyte-colony-stimulating factor (G-CSF), and granulocyte-macrophage colony-stimulating factor (GM-CSF) are molecularly distinct cytokines acting on separate receptors. The release of these cytokines can be concomitantly induced by the same signal and from the same cellular source, suggesting that they may cooperate. Administered alone, human recombinant (hr)IL-1 alpha and hrTNF alpha protect lethally irradiated mice from death, whereas murine recombinant GM-CSF and hrG-CSF do not confer similar protection. On a dose basis, IL-1 alpha is a more efficient radioprotector than TNF alpha. At optimal doses, IL-1 alpha is a more radioprotective cytokine than TNF alpha in C57BL/6 and B6D2F1 mice and less effective than TNF alpha in C3H/HeN mice, suggesting that the relative effectiveness of TNF alpha and IL-1 alpha depends on the genetic makeup of the host. Administration of the two cytokines in combination results in additive radioprotection in all three strains. This suggests that the two cytokines act through different radioprotective pathways and argues against their apparent redundancy. Suboptimal, nonradioprotective doses of IL-1 alpha also synergize with GM-CSF or G-CSF to confer optimal radioprotection, suggesting that such an interaction may be necessary for radioprotection of hemopoietic progenitor cells.
Development of rat anti-mouse interleukin 3 monoclonal antibodies which neutralize bioactivity in vitro.
Authors: Abrams J S , Pearce M K 
Published: December 2022

Abstract
Several rat anti-mouse interleukin 3 (IL-3) monoclonal antibodies have been developed which inhibit the biologic activity of mouse IL-3. These antibodies were produced in rats immunized with preparations of purified, recombinant mouse IL-3, obtained from transiently transfected COS7 cell supernatant. Hybridomas secreting anti-IL-3 were selected initially either on the basis of their giving a positive signal in an indirect enzyme-linked immunosorbent assay, or for their ability to inhibit the proliferation of the IL-3-dependent mouse mast cell line, MC/9. Neutralizing rat monoclonal IgG1, IgG2a, and IgG2b antibodies have been identified; these also block IL-3-induced proliferation of the NFS-60 and IC2 cell lines. These antibodies also blocked the IL-3-induced proliferation of mouse bone marrow-derived colony-forming units-culture suggesting that the same epitopes on IL-3 influence receptor recognition for both the proliferation of factor-dependent cell lines as well as normal bone marrow cells. Fab fragments produced from certain of the IgG2a-neutralizing antibodies blocked as well as the parent IgG. Antibody cross-blocking studies identified one neutralizing antibody apparently recognizing an epitope that was spatially distinct from those recognized by the other blocking antibodies tested. The development of these neutralizing rat monoclonal antibodies to mouse IL-3 should facilitate further investigation on the role of this factor in hemopoietic regulation.
Human Ia alpha- and beta-chains are sulfated.
Authors: Sant A J , Zacheis M , Rumbarger T , Giacoletto K S , Schwartz B D 
Published: December 2022

Abstract
The human Ia antigens (DR, DQ, and DP), determined by genes with the HLA complex, are heterodimers consisting of a 34,000-Da alpha-chain glycoprotein and a 29,000-Da beta-chain glycoprotein. During the course of studies characterizing a recently described sulfated proteoglycan that is specifically associated with Ia, we discovered that there were also nonproteoglycan sulfated components present in the Ia immunoprecipitates. One-dimensional sodium dodecyl sulfate-gel analysis of these latter sulfated components derived from both DR and DQ immunoprecipitates indicated that these components have mobilities indistinguishable from conventional Ia alpha and beta glycoproteins. Two-dimensional gel analysis confirmed these findings and revealed that Ia-associated invariant proteins are sulfated as well. The sulfate moiety was not removed by endoglycosidase F treatment, suggesting that the protein portion of the molecule was sulfated. These results indicate that Ia alpha-, beta-, and invariant chains can be sulfated and raise the possibility that sulfation may play a role in the physiology of Ia molecules.
Immunoregulatory functions of paf-acether. I. Effect of paf-acether on CD4+ cell proliferation.
Authors: Dulioust A , Vivier E , Salem P , Benveniste J , Thomas Y 
Published: December 2022

Abstract
Paf-acether or platelet-activating factor (1-0-alkyl-2-acetyl-sn-glycero-3-phosphocholine) is a phospholipid mediator of inflammation initially described as a potent platelet-aggregating compound. It is newly formed by a variety of cells including monocytes and is now recognized as a major mediator of cell-cell interactions. The present studies were undertaken to determine whether paf-acether could modulate T cell function. We found that addition of paf-acether to CD4+ cells cultured with phytohemagglutinin markedly inhibited the proliferative response in a dose-dependent manner. Maximal inhibition occurred when paf-acether was present during the first 24 hr of cell culture and the presence of paf-acether did not alter the kinetics of CD4+ cell proliferation. Importantly, the mechanism by which paf-acether inhibited the proliferative response was not related to inhibition of interleukin 2 (IL-2) secretion since the amount of IL-2 in cultures was not altered and addition of exogenous IL-2 failed to restore the CD4+ cell proliferative response. Further, as judged by indirect immunofluorescence, paf-acether did not inhibit IL-2 receptor expression. Taken together, these data indicate that paf-acether interferes with some processes leading to CD4+ cell proliferation. This new role for the chemically defined monokine paf-acether emphasizes the potential role of inflammatory lipid mediators in the regulation of T cell response.
Calcium-dependent intracellular acidification dominates the pH response to mitogen in human T cells.
Authors: Gelfand E W , Cheung R K , Grinstein S 
Published: December 2022

Abstract
The effects of a phorol ester and a mitogenic lectin on the intracellular pH (pHi) of human T lymphocytes was investigated. In contrast to the cytoplasmic alkalinization induced by 12-0-tetradecanoylphorbol-13-acetate, an acidification was recorded in cells treated with phytohemagglutinin. This decrease in pHi was magnified in Na+-free medium or in the presence of amiloride analogues, suggesting that activation of Na+/H+ exchange partially counteracts the phytohemagglutinin-induced acidification. The decrease in pHi was dependent on a sustained increase in cytosolic free Ca2+ and could be mimicked by addition of the divalent cation ionophore, ionomycin. The elevation of cytosolic free Ca2+ leads to metabolic H+ (equivalent) generation with consequent cytoplasmic acidification, which in human T cells predominates over the concurrent activation of the Na+/H+ antiport. These findings argue against the notion that activation of Na+/H+ exchange is a signal for the initiation of proliferation.
Patterns of immunoenhancement and suppression induced by Chlamydia trachomatis in vivo and in vitro.
Authors: Levitt D , Corlett R 
Published: December 2022

Abstract
We investigated the cycle of immune enhancement and suppression seen in mice infected with Chlamydia trachomatis by using in vivo and in vitro model systems. BALB/c mice injected intravenously with chlamydia reveal a three- to seven-fold increase in numbers of plaque-forming cells producing antibodies against sheep red blood cells (SRBC), when immunized with SRBC 0 to 5 days after chlamydia infection. When mice are injected with SRBC 10 to 15 days after initial chlamydia infection, the specific anti-SRBC plaque-forming cell response is suppressed two- to three-fold. In vitro, low numbers (2 to 5 X 10(6) bacteria/ml) of chlamydia stimulate potent proliferative responses by B lymphocytes while high numbers (25 X 10(6) bacteria/ml) of bacteria generate strong, general T suppressor activity. This model has important implications for regulation of immune responses that arise at different times during chlamydial infections, as well as for the potential effectiveness of chlamydial vaccines.