bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interleukin 2-activated human lymphocytes exhibit enhanced adhesion to normal vascular endothelial cells and cause their lysis.
Authors: Damle N K , Doyle L V , Bender J R , Bradley E C 
Published: December 2022

Abstract
When cultured with native or recombinant interleukin 2 (IL 2), human lymphoid cells proliferate and acquire the ability to lyse both NK-sensitive and NK-resistant tumor targets. Such IL 2-activated killer (IAK) cells generally do not destroy nonmalignant nontransformed cells. Due to their apparent specificity for tumor cells, adoptive immunotherapeutic trials of IAK cells and IL 2 have been initiated, with promising results. However, infusion of high doses of IL 2 causes systemic toxicity in patients and experimental animals resulting in the development of a vascular leakage syndrome. Certain aspects of such toxicity suggest IL 2-induced, cell-mediated destruction of normal tissue. This study examines the interaction between IL 2-induced human lymphoid cells and endothelial cells (EC). IL 2, in a dose-dependent manner, causes lymphocytes to strongly adhere to EC, but not to tumor cells, fibroblasts, or epithelial cells. In addition, these IL 2-activated lymphocytes were highly cytotoxic not only to NK-resistant Daudi cells but also to vascular and corneal EC. The IAK cells caused lysis of not only human EC but also bovine EC. Although IAK cells did not display significant adherence to normal human fibroblasts or epithelial cells, when brought together by 50 X G centrifugation, these targets were lysed by IAK cells. The ability to lyse EC was not confined to any single subpopulation of IL 2-activated lymphocytes. The lysis of EC was mediated by both IL 2-activated large granular lymphocytes and small agranular lymphocytes. Furthermore, cells within both CD4+ and CD8+ sublineages of T cells, and also non-T subpopulations, mediated IL 2-induced cytolysis of EC. The destruction of EC by IAK cells may contribute in part to the systemic toxicity associated with infusions of high doses of IL 2.
Characterization of monoclonal nonspecific suppressor factor (MNSF) with the use of a monoclonal antibody.
Authors: Nakamura M , Ogawa H , Tsunematsu T 
Published: December 2022

Abstract
The secretion of immunoglobulin (Ig) from cultured mononuclear cells by lipopolysaccharide (LPS) stimulation is inhibited by monoclonal nonspecific suppressor factor (MNSF), a lymphokine produced by murine T cell hybridoma. In an attempt to develop a murine monoclonal antibody (MAb) with specific reactivity against MNSF, a cell fusion technique that incorporated immune murine splenocytes and HAT-sensitive murine myeloma cells was used. Cross-reactivity experiments confirmed that the MAb (MO6) does not bind to unrelated proteins such as bovine serum albumin, mouse IgG, and murine interferon-gamma (IFN-gamma). There are no effects when anti-IFN-gamma antibodies are used with MNSF. As far as biological activity is concerned, MO6 inhibits in vitro the activity of MNSF in terms of the Ig secretion from cultured lymphocytes. By using MO6, affinity chromatography and immunoblotting were performed. The MNSF on the SDS-PAGE showed a band with m.w. of approximately 70,000, indicating the formation of an aggregate in saline; but after treatment with 0.4 M pyridine-acetic acid buffer, separate bands of 24,000 and 16,000 daltons were evident. Therefore MO6 recognizes 70,000 and both 24,000 and 16,000 daltons. Thus we confirmed by using this MAb and affinity chromatography, the existence of human counterpart, human nonspecific suppressor factor (hNSF), in supernatant from concanavalin A-stimulated T cells. When hNSF was fractionated by high pressure liquid chromatography (HPLC), the activity was found in a region corresponding to 70,000 daltons. However, when fractionated in pyridine-acetic acid buffer, hNSF activity was distributed in a slightly wider range of 15,000 to 30,000 daltons. Physicochemical analysis showed that the purified hNSF is resistant to either heating at 56 degrees C or to 2-mercaptoethanol treatment; however, it is labile to acidification at pH 2.0 and is also sensitive to protease treatment, the characteristics of which were similar to those of murine MNSF. Thus MO6 was confirmed to be a pertinent tool for isolation of hNSF, as well as for murine MNSF.
Comparison of subcellular activation of the human neutrophil NADPH-oxidase by arachidonic acid, sodium dodecyl sulfate (SDS), and phorbol myristate acetate (PMA).
Authors: Cox J A , Jeng A Y , Blumberg P M , Tauber A I 
Published: December 2022

Abstract
The phorbol myristate acetate (PMA) stimulation of the human neutrophil NADPH-oxidase has been demonstrated through the activation of protein kinase C (PK-C), using light membrane fractions from nitrogen-cavitated cells. Both arachidonic acid (AA) and sodium dodecyl sulfate (SDS) can also generate an active oxidase in cellfree systems. That the source of O2- with AA and SDS activation is the same NADPH-oxidase as previously studied was confirmed by the similar pH optima and Km values for NADPH as those previously described for the O2- -generating activity harvested from pre-stimulated human neutrophils. In contrast to the stimulation by PMA, however, the stimulation of the NADPH-oxidase by AA and SDS does not appear to require protein kinase C activation: the action of AA and SDS is independent of the addition of PK-C cofactors to the system, and the inhibitor of PK-C activity, H-7, had no effect on the stimulation by AA or SDS. AA and SDS activation are comparable, but the level of NADPH-oxidase expression is sixfold greater with each of these agents than that obtained with a reconstituted PK-C system. The basis of this difference in oxidase expression is unclear, but these findings suggest strongly that although activated PK-C is capable of stimulating a dormant NADPH-oxidase in a cellfree system, this is not the sole pathway for oxidase activation.
Mast cells are not required for anaphylatoxin-induced ileal smooth muscle contraction.
Authors: Stimler-Gerard N P , Galli S J 
Published: December 2022

Abstract
The complement-derived anaphylatoxin peptides, C3a and C5a, have long been considered to manifest their spasmogenic activities primarily through stimulation of mast cells. Although mast cells represent the major non-circulating repository for histamine, these cells also elaborate a number of additional, highly potent spasmogenic mediators derived from arachidonic acid. The same lipid mediators can be released by many other cell types. As a result, evaluation of the role of mast cells in anaphylatoxin-dependent responses cannot be based exclusively upon an analysis of the mediators released. We evaluated the role of mast cells in anaphylatoxin-induced ileal smooth muscle contractions by testing isolated segments of ileal tissues derived from genetically mast cell-deficient mice and their congenic normal (+/+) littermates. Isolated tissues from either congenic normal (+/+) or mast cell-deficient Sl/Sld mice responded similarly to acetylcholine, histamine, serotonin, prostaglandin E2, and the thromboxane A2 analog, U-46619. At 1 microgram/ml, histamine induced contractions of greater magnitude in tissues from mast cell-deficient animals; however, this mediator also desensitized the tissues to repeat challenge with histamine at the same concentration. C5a at 1 nM resulted in contractions equivalent to approximately 50% of the maximal KCl response; normal and mast cell-deficient tissues responded in a similar manner. C5a also released histamine from the normal mouse ileum, in addition to causing contraction of the tissues. C3a at 200 nM also produced similar contractile responses in both +/+ and S1/S1d tissues. These studies show that the anaphylatoxin peptides C3a and C5a are capable of contracting smooth muscle-containing tissues by a mechanism completely independent of mast cells. In addition, we also demonstrated that mast cell degranulation does not necessarily provoke ileal contraction. Thus compound 48/80, a mast cell degranulating agent unrelated to the anaphylatoxins, did not induce contractions in ileal tissues, even when used at concentrations as high as 100 micrograms/ml. Compound 48/80 did release histamine from the +/+ ileum, however, indicating that the agent was able to cause degranulation of ileal mast cells. Taken together, these data indicate that spasmogenic responses to anaphylatoxins (and possibly other agents) that are associated with mast cell degranulation need not necessarily require mast cell mediator release for their expression.
Expression and functional significance of the J11d marker on mouse thymocytes.
Authors: Crispe I N , Bevan M J 
Published: December 2022

Abstract
Subpopulations of thymocytes have been characterized phenotypically and functionally in relation to their expression of the marker defined by the monoclonal antibody J11d. Cortical-type L3T4+, Lyt-2+ thymocytes are all J11d+. Thymocytes that share the phenotype L3T4-, Lyt-2+ with peripheral Lyt-2+ T cells contain a J11d+ and a J11d- subset. These J11d- cells behave like peripheral Lyt-2+ T cells in two functional assays: they form clonal growth bursts in response to immobilized antibody against the T cell antigen receptor, and they act as precursors of alloreactive cytotoxic T cells. The J11d+ cells are inert in both of these assays. In contrast, L3T4+, Lyt-2- thymocytes do not contain a J11d+ subset.
Cytotoxic T cell activation by class I protein on cell-size artificial membranes: antigen density and Lyt-2/3 function.
Authors: Goldstein S A , Mescher M F 
Published: December 2022

Abstract
The role of antigen surface density, and its relationship to the function of the Lyt-2/3 complex, in recognition and triggering of allospecific cytotoxic T lymphocyte (CTL) precursors has been studied by using a novel type of Class I protein-bearing artificial membrane. The cell-size membranes, termed pseudocytes (artificial cells), can be handled like cells but have a well-defined and easily quantitated surface composition. Class I antigen on these membranes stimulated generation of secondary in vitro allogeneic CTL responses as effectively as allogeneic spleen cells, provided that lymphokines were added to the cultures. Antigen density on the pseudocyte surfaces could be varied over a wide range and quantitated by papain cleavage and fluorescence-activated cell sorter analysis. Recognition and triggering of precursor CTL was found to be dramatically dependent on the surface density of antigen and displayed a marked threshold density requirement, below which little or no response occurred. Examination of the effects of anti-Lyt-2 antibody on responses to pseudocytes provided direct evidence for a reciprocal relationship between antigen density and susceptibility to antibody blockade. The results strongly suggest that antigen density is likely to have important biological consequences in control of immune responses. They also show that if Lyt-2/3 functions by interaction with a ligand, then that ligand is the Class I protein.
Characterization of an immunosuppressive factor derived from colon cancer cells.
Authors: Ebert E C , Roberts A I , O'Connell S M , Robertson F M , Nagase H 
Published: December 2022

Abstract
The colon cancer cell line, HT29, produces a soluble substance (HT29 factor) that blocks mitogen-induced T cell proliferation and the production of interleukin 2 (IL 2). Inhibition of T cell proliferation by the HT29 factor is reversible and is not due to a decline in cell viability or an alteration in the kinetics of T cell proliferation. It occurs even when the HT29 factor is added only 24 hr before terminating the T cell cultures, indicating that the factor affects cell division after activation of T cells has already occurred. No inhibitory activity was found in medium conditioned by human colonic epithelial cells or fibroblasts. The factor has an apparent m.w. of 56,000 and an isoelectric point of 7.9. It is sensitive to endopeptidases, heating to 56 degrees C, and extremes of pH. The HT29 factor also suppresses IL 2 production by T cells. However, low IL 2 availability alone cannot account for the suppressive effect of the factor on T cell proliferation, because the addition of exogenous IL 2 does not reverse the inhibition. This block in IL 2 responsiveness is not primarily due to a decrease in IL 2 receptors because Tac expression on activated T cells is minimally decreased during a 24-hr exposure to the HT29 factor. In addition, IL 2-induced proliferation of mitogen-activated T cells is inhibited only slightly by the HT29 factor, indicating that a block in the interaction of IL 2 with its receptor is not its main mechanism of action. Thus the inhibition of T cell proliferation is likely to be due primarily to a mechanism independent of IL 2.
Detergent solubilization of the interleukin 1 receptor.
Authors: Paganelli K A , Stern A S , Kilian P L 
Published: December 2022

Abstract
Interleukin 1 (IL 1) receptors were solubilized from membranes prepared from murine EL-4 thymoma cells with the zwitterionic detergent 3[(3-cholamidopropyl) dimethylammonio]-1-propanesulfonate (CHAPS). Binding of IL 1 to the solubilized receptor was detected by a polyethylene glycol (PEG) precipitation procedure. Concentrations of CHAPS from 4 to 8 mM were effective in solubilizing the IL 1 receptor. At 10 mM CHAPS, there was some loss in binding activity, whereas 2 mM CHAPS was completely ineffective in solubilizing the receptor. Detergent concentrations of 4 mM were routinely used. The solubilized receptor retains the ability to bind 125I-IL 1 in a specific and saturable manner. Scatchard analysis reveals a single type of high affinity binding site having an apparent dissociation constant (KD) of approximately 1.2 X 10(-10) M. Nearly identical KD values are observed for membrane fractions. There are approximately 400 to 500 fmol receptor/mg protein in the detergent extract, corresponding to a two- to threefold enrichment in the Bmax observed for membranes. There is no loss in receptor activity as determined by complete recovery of the total number of binding sites from membranes after solubilization. Binding kinetics show that apparent steady state for the solubilized receptor is reached after 60 min at 37 degrees C. The binding of 125I-IL 1 is essentially irreversible because relatively little bound ligand can be dissociated from the receptor on the addition of excess unlabeled IL 1 at 37 degrees C. Both human IL 1 alpha and IL 1 beta compete for binding of 125I-IL 1 to the soluble receptor, confirming that IL 1 alpha and IL 1 beta bind to the same receptor. Other recombinant proteins, including interferon-alpha A, interferon-gamma, and interleukin 2 have no inhibitory effect.
Mechanism of recovery from acute virus infection. IV. Questionable role of mononuclear phagocytes in the clearance of lymphocytic choriomeningitis virus from spleens of mice.
Authors: Lehmann-Grube F , Krenz I , Krahnert T , Schwachenwald R , Moskophidis D , Löhler J , Villeda Posada C J 
Published: December 2022

Abstract
After intravenous infection of mice with 10(3) infectious units (IU) the WE strain lymphocytic choriomeningitis (LCM) virus multiplied in the spleens (as in all other major organs), reaching more than 10(8) IU/g of tissue on days 4 to 5. Subsequently, the virus was quickly eliminated, being below detectability usually by day 10. During the time of virus clearance, the mononuclear phagocytes (MNP) of the spleen were activated as revealed by suppression of growth of Listeria monocytogenes and increase of cell-associated hydrolytic enzymes. In athymic nude mice, in whom the MNP system is assumed to be permanently activated, the virus replicated slightly but reproducibly less than in their euthymic counterparts. However, when the MNP were activated by Corynebacterium parvum, virus in spleens attained higher concentrations than in mice not so treated, and the rate of elimination was not altered. In mice whose MNP had been damaged by injection of dextran sulfate 500, the spleen virus titers were also increased, but the subsequent immune elimination was slightly delayed. Activation of spleen MNP was not evident at the time virus was rapidly cleared as a result of transfusion of LCM-immune T lymphocytes. Adoptive immunization was as successful in mice that had been pretreated with gamma-rays or cyclophosphamide, suggesting that replicating cells or their descendants, in particular monocytes, did not participate measurably in the process of elimination. Pretreatments of recipients with dextran sulfate 500 reduced the efficacy of transfused LCM-immune T lymphocytes, but this compound probably directly affected the cells. We interpret these findings to mean that the LCM virus in the mouse's spleen is controlled by a mechanism in which MNP do not play an essential role.
Experimental visceral leishmaniasis: production of interleukin 2 and interferon-gamma, tissue immune reaction, and response to treatment with interleukin 2 and interferon-gamma.
Authors: Murray H W , Stern J J , Welte K , Rubin B Y , Carriero S M , Nathan C F 
Published: December 2022

Abstract
During the first 2 to 4 weeks of progressive visceral infection with the intracellular protozoan, Leishmania donovani, spleen cells from BALB/c mice failed in response to leishmanial antigen to produce either of the activating T cell-derived lymphokines, interleukin 2 (IL 2) or gamma-interferon (IFN-gamma). Four weeks after infection, however, antigen-induced IL 2 and IFN-gamma secretion emerged and coincided with the onset of control over parasite replication and the subsequent killing of greater than 80% of intrahepatic L. donovani. The development of this immunosecretory activity correlated with the hepatic tissue response at the site of parasitized Kupffer cells. This response progressed from Kupffer cell fusion (week 1) to fusion plus a mononuclear cell infiltrate (week 2) to well-organized granuloma formation (weeks 4 to 8). In contrast, T cell-deficient nude BALB/c mice exerted no control over L. donovani, their spleen cells failed to generate antigen-induced IFN-gamma, and at 4 weeks, their livers were devoid of any tissue reaction. Since spleen cells from 2-week infected normal mice did not produce antigen-stimulated IL 2 or IFN-gamma, these mice were treated with recombinant (r) lymphokines. Various protocols using both high and low dose human rIL 2 had no antileishmanial effect. Hepatic parasite replication was completely halted, however, by macrophage-activating doses of murine rIFN-gamma. These results reemphasize that an intact T cell-dependent response is required for successful defense against L. donovani, indicate that this immune response can be measured at both the cellular (secretory) and tissue levels, and confirm that IFN-gamma can exert an antileishmanial effect in vivo.
Antibodies define multiple proteins with epitopes exposed on the surface of live Babesia bigemina merozoites.
Authors: McElwain T F , Perryman L E , Davis W C , McGuire T C 
Published: December 2022

Abstract
Babesia bigemina is one of several tick-borne hemoparasitic diseases of cattle that are inadequately controlled and cause substantial livestock production losses in tropical and subtropical climates. Recovery from acute babesiosis is associated with development of protective immunity against subsequent challenge with both homologous and heterologous parasites. Viable and infectious merozoites, the intraerythrocytic stage of B. bigemina responsible for clinical disease, were separated from contaminating host cells by density gradient centrifugation. Monoclonal antibodies developed against gradient-separated merozoites were screened for surface reactivity against live merozoites in an immunofluorescent binding assay. Surface-reactive antibodies immunoprecipitated five major biosynthetically radiolabeled merozoite proteins with relative m.w. of 72,000, 58,000, 55,000, 45,000, and 36,000 in SDS-PAGE. Two additional proteins immunoprecipitated with the 45,000 m.w. protein were unreactive with monoclonal antibody in western blots and are apparently part of a membrane complex co-precipitated by this antibody. In contrast, additional proteins of m.w. of 36,000, 35,000, and 33,000, immunoprecipitated with the 58,000 protein, all contain the surface-exposed epitope bound by monoclonal antibody. Immune serum from an animal that had recovered from infection with a Mexico isolate of B. bigemina immunoprecipitated five radiolabeled proteins from the Mexico isolate that co-migrated in SDS-PAGE with major proteins precipitated by surface-reactive monoclonal antibodies. In addition, antibodies against a Kenya isolate of B. bigemina immunoprecipitated the same co-migrating proteins from radio-labeled Mexico isolate, demonstrating epitope conservation between surface proteins of geographically different isolates. The identification of proteins with epitopes exposed on the surface of live merozoites and accessible to antibody provides candidates to be tested as protective immunogens in cattle.
T cell surface markers expression by immature human thymocytes in in vitro culture: role of Ia+ accessory cells.
Authors: Larocca L M , Piantelli M , Maggiano N , Musiani P 
Published: December 2022

Abstract
Previous studies have indicated that the human thymus is composed of several discrete compartments. Cortical thymocytes are reactive with the monoclonal antibody anti-T6, whereas most medullary cells, unreactive with anti-T6, stain brightly with anti-T3 antibody, which defines mature T cell populations. By using an indirect immune rosette method, we isolated the minor thymocyte population (1 to 2% of all thymocytes) lacking both T3 and T6 but expressing T11 antigens. These cells could be maintained in culture supplemented with recombinant IL 2 (Rec-IL 2) for several days. Under these conditions, T3-T6- cells were shown to undergo phenotypic changes. In the absence of thymic macrophage (Mo), T3+ and T8+ thymocytes appeared in culture, whereas the development of T4+ cells strictly required the presence of Mo. The expression of T4 antigen could be largely prevented by the addition of anti-HLA-DR antibody, further indicating that Ia+ accessory cells had the ability to promote in vitro development of T4+ thymocytes. In the presence of Mo, not only T4+ but also T8+ cells were obtained. Double fluorescence staining with anti-T8-FITC and anti-T4-biotin demonstrated that after 12 days of culture, T4 and T8 antigens were mutually exclusive. Furthermore, during the course of these studies, we observed that under the culture conditions utilized (e.g., presence or absence of Mo), T3-T6-thymocytes failed to express the T6 antigen. Thus, the in vitro development of T cells bearing a mature phenotype could be obtained in the absence of intermediate expression of cortical (T6+) thymocytes.