bluuebunny/crossref_metadata_2025_split huggingface dataset:
Allogeneic MHC antigen requirements for lupus-like autoantibody production and nephritis in murine graft-vs-host disease.
Authors: Portanova J P , Ebling F M , Hammond W S , Hahn B H , Kotzin B L 
Published: December 2022

Abstract
A graft-vs-host (GVH) reaction of parental T cells in allogeneic F1 mice can lead to an autoimmune disease resembling human SLE. We analyzed the contribution of MHC genes to the development of IgG antinuclear antibody production and immune complex glomerulonephritis in MHC-congenic F1 recipients. DBA/2 T cells elicited IgG antibodies to histone, ssDNA, and dsDNA in all histoincompatible F1 recipients that were studied. The anti-DNA antibody responses were quantitatively similar among the F1 combinations and displayed comparable IgG2a subclass and cationic charge characteristics. In contrast, severe renal disease was manifested only in F1 mice that expressed H-2b encoded class II gene products. Disease susceptibility was associated with a decrease in circulating anti-DNA antibodies and a characteristic localization of immune complexes in the glomeruli. The data suggest that the production of potentially pathogenic IgG anti-nuclear antibodies is not sufficient for the development of renal disease in GVH-induced lupus. Thus, another event separate from autoantibody production is MHC dependent and appears to be critical for the formation and/or deposition of pathologic immune complexes.
IL-1-induced adhesion of polymorphonuclear leukocytes to cultured human endothelial cells. Role of platelet-activating factor.
Authors: Breviario F , Bertocchi F , Dejana E , Bussolino F 
Published: December 2022

Abstract
In early studies we found that IL-1 stimulated endothelial cells (EC) to produce platelet-activating factor (PAF, 1-alkyl-2-acetyl-sn-glycero-3-phosphocholine). Inasmuch as this phospholipid has a wide range of biologic activities, including polymorphonuclear leukocytes (PMN) aggregation and chemotaxis, we investigated whether EC-associated PAF could contribute to IL-1-induced PMN adhesion to EC. When four selective PAF antagonists were added to IL-1-stimulated EC during the PMN adhesion assay, adhesion was reduced in a concentration-related way. Similarly, pre-treatment of PMN with PAF before the adhesion assay to induce desensitization to this phospholipid reduced PMN adhesion to IL-1-treated EC. However, comparing the time course and the concentration response curve of IL-1-induced EC adhesivity and PAF synthesis, we found that increased EC adhesivity to PMN required a shorter incubation time and lower concentration of IL-1 to become apparent than PAF production. When acetyl-coenzyme A was added to EC cultures at a concentration that raised PAF synthesis by 60%, no significant increase in PMN adhesion was observed. In addition, after 9 to 10 doublings, the EC ability to synthesize PAF decreased by 85 to 90%, whereas IL-1-induced EC adhesivity to PMN was only slightly diminished. When IL-1-alpha and -beta were tested on EC, we observed that both were equally active in promoting PMN adhesion to EC but only the alpha-form was able to stimulate PAF production. When PMN were seeded on IL-1-treated EC, increased amounts of PAF were detected even when EC were fixed; in addition, the inhibitory effect of a PAF antagonist was evident also in these conditions. Overall these results indicate that IL-1-induced PAF production by EC does not significantly contribute to PMN adhesion to them. We hypothesize that the observed inhibitory effect of PAF antagonists and PAF desensitization of PMN might be directed at PAF produced by PMN themselves during adhesion to IL-1-treated EC.
The physical-chemical characterization and biologic activity of serum released lipopolysaccharides.
Authors: Tesh V L , Morrison D C 
Published: December 2022

Abstract
As a result of the incubation of Escherichia coli in normal human serum, a finite fraction of LPS is released from the bacterial membrane. Approximately half of the LPS released by the action of serum (S-LPS) exists in association with serum proteins in a lower m.w. form than that manifest in phenol-water extracted LPS preparations. The two major LPS-serum protein complexes have apparent Mr of 68 and 32 kDa. The LPS subunit heterogeneity of S-LPS, however, does not appear to differ significantly from LPS retained on the bacteria after serum treatment, or from LPS derived by lysis of whole cells. The biologic activities of S-LPS and phenol-water extracted LPS examined in these studies, differed significantly. In contrast to phenol-water extracted LPS, S-LPS was 1) reduced in lethal toxicity for sensitized mice; 2) reduced in Limulus reactivity; 3) a more potent murine splenocyte mitogen; 4) reduced in the capacity to elicit extracellular, but not membrane-associated IL-1; and 5) reduced in the ability to mediate TNF production. These data suggest that humoral "detoxification" of LPS may involve, in part, the formation of LPS-serum protein complexes with reduced capacities to elicit extracellular cytokine production, whereas the immunomodulatory effects of LPS appear to be enhanced.
Agents that mimic antigen receptor signaling inhibit proliferation of cloned murine T lymphocytes induced by IL-2.
Authors: Nau G J , Kim D K , Fitch F W 
Published: December 2022

Abstract
We have shown previously that stimulation of cloned murine T lymphocytes via the TCR inhibits their responsiveness to rIL-2. Signaling via the TCR is believed to result in a variety of biochemical events that include a rise in intracellular free calcium and activation (translocation) of protein kinase C. These two signals also can be generated by calcium ionophores, such as ionomycin, and by activators of protein kinase C, such as PMA. We report here that treatment of cloned murine T lymphocytes with PMA, ionomycin, or the combination led to a dose-dependent inhibition of IL-2-dependent proliferation but did not inhibit lymphokine secretion. Concentrations of PMA and ionomycin that maximally inhibited proliferation stimulated maximal lymphokine secretion and increased mitochondrial activity as assessed by measurement of cleavage of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium-bromide. Furthermore, PMA, ionomycin, the combination, or immobilized anti-CD3 mAb added after 12 to 16 h of culture with IL-2 could inhibit proliferation. These results demonstrate that PMA and ionomycin mimic stimulation of the TCR by high concentrations of immobilized anti-TCR mAb in that proliferation is inhibited and lymphokine secretion is induced. In addition, PMA or ionomycin could independently inhibit proliferation of some cells. These findings suggest that alternative mechanisms exist to regulate proliferation. Either increased levels of intracellular calcium or the physiologic events corresponding to those induced by PMA can inhibit IL-2-dependent replication of T lymphocytes.
The stem cell antigens Sca-1 and Sca-2 subdivide thymic and peripheral T lymphocytes into unique subsets.
Authors: Spangrude G J , Aihara Y , Weissman I L , Klein J 
Published: December 2022

Abstract
Stem cell Ag 1 and 2 (Sca-1 and Sca-2), so named due to their expression by mouse bone marrow stem cells, were evaluated for expression by populations of cells within the thymus. Immunohistochemical analysis demonstrated that Sca-1 was expressed by cells in the thymic medulla and by some subcapsular blast cells, as well as by the thymic blood vessels and capsule. Sca-2 expression, which was limited to the thymic cortex, could be associated with large cycling thymic blast cells. Both Sca-1 and Sca-2 were expressed on a sub-population of CD4-CD8- thymocytes, and this subpopulation was entirely contained within the Ly-1lo progenitor fraction of cells. Sca-1 expression by a phenotypically mature subset of CD4+CD8- thymocytes was also noted. Conversely, Sca-2 expression was observed on a phenotypically immature or nonmature subpopulation of CD4-CD8- thymocytes. MEL-14, an antibody that defines functional expression of a lymphocyte homing molecule, identified a small population of thymocytes that contained all four major thymic subsets. Sca-2 split the MEL-14hi thymocyte subset into two Sca-2+ non-mature/immature phenotype fractions and two Sca-2- mature phenotype fractions. In peripheral lymphoid organs, Sca-1 identified a sub-population of mature T lymphocytes that is predominantly CD4+CD8-, in agreement with the thymic distribution of Sca-1. Peripheral T cells of the CD4-CD8+ phenotype were predominantly Sca-1-. In contrast, Sca-2 did not appear to stain peripheral T lymphocytes, but recognized only a subset of B lymphocytes which could be localized by immunohistochemistry to germinal centers. Thus, expression of Sca-1 is observed throughout T cell ontogeny, whereas Sca-2 is expressed by some subsets of thymocytes, including at least one half of thymic blasts, but not by mature peripheral T lymphocytes.
Phenotypic and functional characterization of human T cell clones.
Authors: Patel S S , Duby A D , Thiele D L , Lipsky P E 
Published: December 2022

Abstract
The capacity of human peripheral blood-derived T cell clones to carry out a variety of functions was examined. T cell clones were generated by stimulating individual peripheral blood T cells with PHA by a procedure that yielded a growing clone from a mean of greater than 92% of the cultured cells. A total of 65 T cell clones (44 CD4+ and 21 CD8+) generated from two individual donors were examined for their functional capabilities. All T cell clones examined secreted IL-2, IFN-gamma, and lymphotoxin/tumor necrosis factor like activity when stimulated with immobilized mAb to the CD3 complex (64.1). When 54 additional T cell clones from a third donor were analyzed, all were found to produce IL-2. Upon activation with immobilized 64.1, all CD4+ clones and 91% of the CD8+ clones induced the generation of Ig-secreting cells from purified B cells. The CD8+ clones that did not serve as Th cells alone were able to augment the capacity of fresh CD4+ cells to generate Ig-secreting cells. Each of these clones was also found to effect MHC-unrestricted cytotoxicity upon activation with immobilized 64.1. The CD8+ clones were somewhat more effective killers than CD4+ clones, although there was considerable overlap. A total of 18 clones was analyzed for TCR beta-chain gene rearrangement. Of the clones exhibiting rearrangements of the beta-chain gene, 94% were found to have a single rearrangement pattern. Finally, the detailed phenotype of 15 (11 CD4+ and 4 CD8+) of these clones was examined. Variable numbers of cells of each of the clones expressed Ag identified by mAb 4B4 (CD29), Leu 8, Leu 15 (CD11b), and NKH1. Moreover, cells of 6 of 11 CD4+ clones and 4 of 4 CD8+ clones also expressed CD45R in addition to CD29; expression of CD45R and CD29 varied with the activation status of the clone. The current data demonstrate that nearly all of the T cell clones were able to accomplish each of the functions examined regardless of the surface phenotype. Inasmuch as the clones were generated using a technique that expanded more than 92% of the circulating T cells, the data imply that the progeny of the vast majority of T cells may have the inherent capacity to exert a wide array of functional activities.
Analysis of expression of CD2, CD3, and T cell antigen receptor molecules during early human fetal thymic development.
Authors: Haynes B F , Singer K H , Denning S M , Martin M E 
Published: December 2022

Abstract
To define early stages of T cell maturation during human fetal thymic development, we have used mAb reactive with CD2, CD3, and TCR molecules in indirect immunofluorescence assays on a series of early human fetal thymic specimens. Using a technique of quantitating the relative proportions of fluorescent-positive cells present in tissue sections, we found at 8.5 wk of gestational age after arrival of CD7+ T cell precursors into the thymic rudiment, 60% of thymic CD7+ cells were CD2+, 4% were CD3+ and none was TCR-delta+ or TCR beta+. Moreover, cells reactive with anti-CD2 antibodies against T11(2) and T11(3) epitopes of CD2 as well as thymic stromal cells expressing the CD2 ligand, lymphocyte function associated Ag-3, were also present at 8.5 wk. From 9.5 wk to birth TCR beta+ cells increased to include greater than 90% of all CD7+ cells while TCR-delta+ cells fell from a peak of 11% of CD7+ cells at 9.5 wk to 1% of CD7+ cells at birth. These data suggest that epitopes of CD2 molecules are expressed early on during fetal thymic development. Moreover, these data suggest that CD7+, CD2+, cytoplasmic CD3+ T cell precursors in man give rise to both TCR-delta+ T cells as well as to T cells expressing TCR-alpha beta.
Role of CD2 in activation and cytotoxic function of CD8/Leu-7-positive T cells.
Authors: Rüthlein J , James S P , Strober W 
Published: December 2022

Abstract
CD3/CD8-positive, Leu-7-positive cells comprise about 3 to 5% of PBL in normal individuals, but the proportion of these cells is increased in patients with a variety of diseases including chronic viral infection, Crohn's disease, and AIDS. To study further the function of these cells, the proliferative and cytotoxic responses of highly purified CD8/Leu-7-positive cells were studied in vitro. These cells had low proliferative responses when exposed to PHA or mitogenic anti-CD3 mAb compared to CD8/Leu-7-negative cells, and their proliferative responses were significantly lower after addition of IL-2 or autologous adherent cells. However, the proliferative responses of both Leu-7-positive and Leu-7-negative CD8 cells were similar when stimulated with PHA, Ionomycin, or anti-CD3 in combination with phorbol ester. In addition, CD8/Leu-7-positive cells demonstrated high proliferative responses when exposed to a combination of both PHA and SRBC, and these responses could be inhibited by prior addition of non-stimulating anti-CD2.1 mAb. CD8/Leu-7-positive cells, but not CD8/Leu-7-negative cells, mediated lectin- and anti-CD3-induced cytotoxicity against K562 target cells. Cytotoxicity was in part dependent on the CD2 Ag because it was inhibited by anti-CD2.1 mAb. Finally, when small CD8-positive T cells having low cytotoxic potential were activated with PHA plus SRBC, but not PHA alone, there was significant enhancement of their cytotoxic function. Thus, the CD2 receptor may be an important activation pathway for cytotoxic cells.
Active suppression of host-vs graft reaction in pregnant mice. IX. Soluble suppressor activity obtained from allopregnant mouse decidua that blocks the cytolytic effector response to IL-2 is related to transforming growth factor-beta.
Authors: Clark D A , Falbo M , Rowley R B , Banwatt D , Stedronska-Clark J 
Published: December 2022

Abstract
Non-Ts cells in murine allopregnancy decidua release potent immunosuppressor factors in vitro that block the action of IL-2. Previous studies have shown that both primary and secondary CTL responses are inhibited as well as the generation of Il-2 activated killer cells. In this paper we show that the suppressor factor(s) can arrest ongoing IL-2 dependent CTL responses but does not block binding of anti-IL-2R antibody or radiolabeled IL-2 to the IL-2R. The suppressive activity is associated with molecules that adhere to hydroxylapatite and con A-agarose but do not bind to activated charcoal or partition as lipids. HPLC TSK 3000 separation showed a major peak of suppressive activity at 60 to 100 kDa, with additional activity at 300 kDa, and at less than 1000. Under acid conditions, suppressive activity resolved as a major peak at 13 kDa with some residual activity at 65 kDa and at less than or equal to 1000. A specific rabbit IgG antibody to transforming growth factor-beta neutralized suppressor activity in unseparated supernatant and in the 13-kDa fraction whereas neutralizing antibodies to progesterone or PGE-2 did not affect suppression but could neutralize their respective ligands. Inasmuch as transforming growth factor-beta has a 25 kDa Mr, the 13-kDa decidua-associated suppressor factor would appear to represent a related but distinct regulatory molecule that associates with a variety of carrier molecules.
The construction and characterization of a biologically active recombinant IL-2 containing a lysine-rich C-terminal extension.
Authors: Lin Y , Robb R J , Gray J E , Simon P 
Published: December 2022

Abstract
A polylysine extended gibbon IL-2 (IL-2-L) was constructed by the addition of a lysine-rich oligopeptide, Gly3-(Lys-Lys-Asp)3-Leu-Glu to the C terminus of gibbon IL-2 by using rDNA technology. The bioactivity of the hybrid molecule was comparable to that of normal human rIL-2 in assays measuring T cell proliferation, and in generation of lymphokine-activated killer cells from PBL. Furthermore, the addition of the lysine-rich segment made the molecule more amenable to the chemical derivatization of amino groups. After biotinylation, IL-2-L retained a greater proportion of its bioactivity than normal rIL-2. In addition, biotinylated IL-2-L was capable of simultaneously binding to cell surface IL-2R and streptavidin. Thus, the addition of the lysine-rich oligopeptide facilitated the generation of an active form of biotinylated IL-2 which acts as a bridge between IL-2R-positive cells and avidin-coupled reagents and affinity supports. Such a selective means of labeling and binding IL-2-responsive cells may have great practical utility for IL-2-based immunotherapy.
Characterization of CD45 and CD45R monoclonal antibodies using transfected mouse cell lines that express individual human leukocyte common antigens.
Authors: Streuli M , Morimoto C , Schrieber M , Schlossman S F , Saito H 
Published: December 2022

Abstract
Five cell lines that express one of five isoforms of the human leukocyte common Ag (CD45) were established by transfecting a murine pre-B cell line with leukocyte common Ag cDNA constructs. Using these cell lines, the specificities of CD45 and CD45R mAb were examined. Of the 43 mAb tested, 25 antibodies recognized sequences common to all five isoforms, 16 antibodies recognized isoforms that include exon A encoded sequences, one antibody recognized isoforms that include exon B encoded sequences, and one antibody recognized only the isoform that does not include either exon A, B, or C encoded sequences.
Characterization of N-formyl-methionyl-leucyl-phenylalanine receptors on human neutrophils. Effects of isolation and temperature on receptor expression and functional activity.
Authors: Tennenberg S D , Zemlan F P , Solomkin J S 
Published: December 2022

Abstract
The study of polymorphonuclear neutrophil (PMN) surface receptor expression provides a means for the assessment of PMN function and state of cellular activation. In this study, we characterized binding of the chemotactic peptide FMLP to whole PMN, with particular attention to those variables that may account for the wide variation reported in the literature. These included avoidance of oxidized FMLP as a radioligand contaminant, determination of the optimal cold ligand concentration necessary for achieving minimal nonspecific binding throughout the range of radioligand concentrations used in saturation experiments (greater than or equal to 5 x 10(-5) M), avoidance of radioligand concentrations that equal or exceed receptor saturation and are not suitable for Scatchard analysis (greater than or equal to 60 to 80 nM), and avoidance of inadvertent receptor mobilization due to room temperature PMN isolation techniques and cell warming. PMN isolated and maintained at 4 degrees C expressed a single, high affinity population of FMLP receptors (approximately 6000 receptors per cell) with a KD of 15.5 nM. These characteristics, and in particular the single-affinity nature of the expressed FMLP receptor site, were derived from saturation experiments and confirmed with agonist competition studies. PMN subjected to room temperature isolation or 37 degrees C warming exhibited a 2.5-fold increase in FMLP receptor expression (approximately 15,000 receptors per cell) without changes in receptor affinity. These latter PMN, in correlation with increased receptor expression, had increased initial, maximal rates of FMLP-induced superoxide generation (10.2 vs 6.3 nmol/min/10(6) PMN for cells isolated and maintained at 4 degrees C) as a manifestation of their functional activation. The avoidance of inadvertent cellular activation during PMN isolation is essential to studies of PMN function, activation and the role of FMLP receptor expression/mobilization in these processes.
Cytotoxic T lymphocyte-defined epitope differences between HLA-A2.1 and HLA-A2.2 map to two distinct regions of the molecule.
Authors: Hogan K T , Clayberger C , Le A X , Walk S F , Ridge J P , Parham P , Krensky A M , Engelhard V H 
Published: December 2022

Abstract
Hemi-exon shuffling and site-directed mutagenesis have been used to determine which amino acid differences between HLA-A2.1 and HLA-A2.2 alter the CTL-defined epitopes on these two molecules. Two genes were constructed that encode novel molecules in which the effect of amino acid differences at residues 9, 43, and 95, or at residue 156 could be separately evaluated. Using both human and murine CTL that were specific for either HLA-A2.1 or HLA-A2.2, four types of epitopes were identified: 1) epitopes that were insensitive to substitutions at either residues 9, 43, and 95, or residue 156 but were lost when all four positions were changed; 2) epitopes that were dependent on the residues 9, 43, 95, but not residue 156; 3) epitopes that were dependent on residue 156, but not amino acid residues 9, 43, and 95; and 4) epitopes that were dependent on residues 9, 43, and 95, as well as amino acid residue 156. Overall, there was a roughly equal distribution of clones recognizing each of these types of epitopes. Additional molecules were constructed by hemi-exon shuffling between the HLA-A2.2 and HLA-A2.3 genes, and by site-directed mutagenesis, to analyze the epitopes recognized by two HLA-A2.2/A2.1 cross-reactive murine CTL that do not recognize HLA-A2.3. Although the epitopes recognized by these CTL were unaffected by changes occurring at residues 9, 43, and 95, or at residues 149, 152, and 156 alone, simultaneous changes in both of these regions acted in concert to destroy the epitopes. Both of the CTL recognized epitopes that were lost when substitutions were made at residues 9, 43, 95, 149, and 152. The epitope recognized by one of the CTL was also destroyed by the substitution of residues 9, 43, 95, 152, and 156. Overall, these results indicate that residues 9, 43, and 95, as well as residues in the alpha-helical region of the molecule, are all capable of contributing to the definition of the epitopes recognized by HLA-A2.1- and HLA-A2.2-specific CTL. They further indicate that some epitopes can be mapped to a particular region of the molecule, whereas other epitopes are formed through a complex interaction of residues in distant regions of the molecule.