bluuebunny/crossref_metadata_2025_split huggingface dataset:
IL-2 receptor expression in autoimmune MRL-lpr/lpr mice. The expanded L3T4-, Lyt-2- population does not express p75 and cannot generate functional high-affinity IL-2 receptors.
Authors: Rosenberg Y J , Nurse F , Begley C G 
Published: December 2022

Abstract
Autoimmune MRL-lpr/lpr mice develop an SLE-like disease characterized by a profound lymphadenopathy within an L3T4-, Lyt-2- (DN), B220+ T-cell population. Despite its immature phenotype this subset expresses mature alpha beta TCR belonging predominantly to the V beta 8 gene family and appears to be identical to an activated form of a minor T cell population present in both the thymus and periphery of normal mice. However, the mechanisms underlying the greatly increased cellularity in lpr/lpr-bearing mice are not understood. In this study, the IL-2R expression of lpr/lpr T cells was examined to assess the contribution of IL-2-mediated division to their expansion. The lpr/lpr DN T cells lacked high-affinity IL-2R, even after stimulation, suggesting that IL-2-dependent proliferation plays no role in the expansion of these cells and demonstrating the existence of this unusual T cell phenotype in vivo.
Regulation of lymphocyte tumor necrosis factor receptors by IL-2.
Authors: Owen-Schaub L B , Crump W L , Morin G I , Grimm E A 
Published: December 2022

Abstract
Activated lymphocytes are known to express TNF receptors. The precise stimuli involved in induction and regulation of these receptors have not been elucidated. Our findings demonstrate that IL-2, alone and in serum-free conditions, can trigger and regulate TNF receptor expression on normal lymphocytes. Flow cytometric analyses demonstrated that the receptor was rapidly induced on CD4, CD8, and CD16+ cells after IL-2 stimulation. Receptors increased with culture duration, became maximal between days 5 and 9, and were maintained for 18 to 20 days in the presence of IL-2. By using 125I-TNF and FITC-TNF binding, we present evidence that IL-2 concentration determines the magnitude of lymphoid TNF receptor expression--influencing both the percentage of TNF-positive cells within the population and the number of receptors/cell. Collectively, our results are persuasive for consideration of IL-2 as a central mediator in the regulation of lymphocyte TNF receptors.
IL-6 and IL-1 synergize to stimulate IL-2 production and proliferation of peripheral T cells.
Authors: Holsti M A , Raulet D H 
Published: December 2022

Abstract
Purified T cells can be induced to proliferate and to produce the autocrine growth factor IL-2 with mAb to the TCR and costimulatory cytokines. In a previous report we demonstrated that human IL-6 stimulates IL-2 production and proliferation of purified T cells, in conjunction with the insolubilized anti-TCR V beta 8 mAb, F23.1. Here we show that when CD4+ T cells are rigorously purified to greater than 99% CD4+CD8-, they respond only weakly to F23.1 and IL-6. Instead, there is an additional requirement for IL-1, which dramatically synergizes with IL-6 to induce prolonged (greater than 7 days) proliferative responses and IL-2 production. Similar results were observed when the highly mitogenic anti-CD3 mAb 145-2C11 was substituted for F23.1. The proliferation induced by F23.1, IL-1, and IL-6 was substantially (greater than 80%) inhibited by a mAb to mouse IL-2, and was not inhibited by an anti-IL-4-mAb. In accordance with this finding, medium conditioned by the activated CD4+ cells contained large amounts of IL-2, which increased over a 7-day culture period. These results demonstrate that IL-6 and IL-1 stimulate T cell proliferation by inducing production of the autocrine growth factor IL-2. In addition, the two lymphokines must be present simultaneously for activation to occur. The possible roles of IL-6 and IL-1 in IL-2 gene regulation and in Ag-induced T cell activation are discussed.
The role of IL-4 in the generation of B lymphocytes in the bone marrow.
Authors: Simons A , Zharhary D 
Published: December 2022

Abstract
It has been indicated that IL-4 supports the maturation of pre-B cells to B lymphocytes. The present study was designed to investigate the mechanism by which IL-4 influences this maturational process. In order to determine whether IL-4 acts directly on pre-B cells, we sorted out B220+, sIg- cells from bone marrow of young adult (C3H X C57BL/6)F1 mice. These purified populations of pre-B cells (greater than 95%) were incubated with and without 4 to 200 U/ml of rIL-4, and the generation of new B lymphocytes in these cultures was followed for several days. We found that the frequency of newly generated B lymphocytes (%sIg+) was similar in control and in IL-4-containing cultures. However, the total number of B lymphocytes was significantly higher in IL-4-containing cultures. This high number of B lymphocytes was a result of an increased survival of cells in IL-4-containing cultures. The effect was IL-4 specific because anti-IL-4 antibodies completely prevented this phenomenon. We thus conclude that IL-4 does not induce the maturation of pre-B cells but may be important in the process of B lymphocytes generation by providing a signal for survival of these cells.
Transient activation of the NADPH oxidase through Fc gamma RI. Oxidase deactivation precedes internalization of cross-linked receptors.
Authors: Pfefferkorn L C , Fanger M W 
Published: December 2022

Abstract
It is well known that Fc gamma R mediate the rapid release of agents of inflammation and, in addition, play an important role in the uptake of stimulatory antibody complexes. Activation of the FcR for human IgG1 (Fc gamma RI) on human monocytic cells triggers a transient activation of the NADPH oxidase. In this study, we tested the possibility that transience of the NADPH oxidase activation might have been the result of rapid internalization of cross-linked Fc gamma RI. Stimulatory receptor moieties were formed by cross-linking Fc gamma RI with receptor-specific mAb that are known to trigger superoxide anion release. The formation of the stimulatory receptor units was determined by quantitating the rate of superoxide anion production through its reduction of cytochrome c. This rate has been found to correlate with the rate of binding of cross-linking antibody and, therefore, the rate of formation of the stimulatory moieties (receptor aggregates). Internalization of cross-linked Fc gamma RI was measured by quantitation of cell-associated FITC-labeled Fc gamma RI-specific mAb resistant to acid elution. We found that cross-linking antibody bound to Fc gamma RI continued to be taken up by the cells well after cessation of oxidase activity. The constant rate of uptake and the differential effect of temperature on these two functions suggested that they are separately regulated. Quantitation of cross-linked receptors that were inactive, i.e., no longer stimulating superoxide anion production, indicated that 50% of internalizable, and therefore cross-linked, Fc gamma RI remained on the surface after oxidase activity had ceased. This evidence of cessation of oxidase activity before the endocytic uptake of mAb/R stimulatory units indicates that the activated state of surface cross-linked Fc gamma RI is of brief duration and that occupation of the receptors by cross-linking-ligand does not sustain the activated state of the receptor. Thus, Fc gamma RI-mediated oxidase activation is temporally limited to the formation of the stimulatory receptor moiety.
The bacterial outer membrane protein that reacts with anti-HLA-B27 antibodies is the OmpA protein.
Authors: Zhang J J , Hamachi M , Hamachi T , Zhao Y P , Yu D T 
Published: December 2022

Abstract
A bacterial outer membrane protein of 35-kDa Mr has been reported to react with several anti-HLA-B27 mAb. Here, we demonstrated that this protein showed the heat-modifiability of the OmpA protein during SDS-PAGE. Further, the protein was not detected in mutants of Escherichia coli in which the expression of the OmpA protein has been suppressed. The protein would be reexpressed when one of the mutants was transformed with an expression vector carrying the OmpA gene. Finally, the identity of the reactive protein to OmpA protein was verified by homology in amino acid sequences. An NH2-terminal fragment of this protein was generated by tryptic digestion. Inasmuch as this was unreactive with the anti-HLA-B27 antibody, we concluded that the carboxyl-terminus contributed directly or indirectly to the reactive domain.
Molecular basis of Qa-11 antigen and paradoxical Qa-gene expression in an H-2 recombinant.
Authors: Soloski M J , Oudshoorn-Snoek M , Einhorn G , Demant P 
Published: December 2022

Abstract
The Qa-11 Ag expressed in certain strains with the B2-microglobulin-b allele, apparently maps into the Tla region as well as into the Qa-2 region. Moreover Qa-11 has been shown to be biochemically indistinguishable from Qa-2. Genetic complementation studies combining the right Qa and Tla regions failed to lead to Qa-11 expression. To elucidate the molecular basis of this apparent paradox, we examined the expression of Qa-11 on products of transfected Q-region class I genes. Immunochemical analysis has shown that the Qa-11 Ag is expressed on class I molecules encoded by the Q7 gene from both C57BL/10 (Q7b) and BALB/c (Q7d), but not on the protein product of the Q9 gene isolated from the C57BL/10 strain (Q9b). Inasmuch as the predicted protein products of the Q7b and Q9b genes would differ at a single amino acid, a residue critical for Qa-11 expression has been identified. Based on these results it is proposed that among the beta-2-mb strains, the Qa-11+/Qa-2+ mice are likely to express at least the Q7 gene, whereas Qa-11-/Qa-2+ mice express only Q9. In support of this model, the Qa-2+/Q-11- recombinant B6.K2, essential for the apparent mapping of Qa-11 into the Tla region, expresses only Q9 but not Q7 encoded molecules on the cell surface, and only Q9 and no processed Q7 mRNA is detected in the cytoplasm. This expression pattern in B6.K2 cannot be explained on the basis of a single crossing-over event.
Clonal diversity in human B cell lymphoma. I. Idiotypic and genetic analysis of lymphoma heterohybrids.
Authors: Rudders R A , Jespersen D L , Zacks J , Sikorski A , DeLellis R A , Krontiris T 
Published: December 2022

Abstract
Secretory heterohybrid clones from seven pristine human B cell lymphomas of diverse histologic types were established to investigate the question of tumor clonal diversity. We found that in six tumors, heterohybrid-derived Ig showed similar band patterns in IEF; families of anti-Id prepared from tumor Ig reacted uniformly with individual heterohybrids and original tumor; and the V gene loci displayed little variation on Southern analysis. In one patient who was followed with serial multiple site biopsies over a 14-mo period, clonal Id was preserved until the final stage of his disease, in spite of cytotoxic treatment. In a single follicular tumor (J.M.), each of the anti-Id reacted uniformly with the parent tumor and the individual heterohybrids, except that three of six clones failed to react with a single anti-Id family member. A Southern analysis of the VH gene locus revealed an identical gene rearrangement that was shared by the parent tumor and each heterohybrid. However, there was considerable heterogeneity of J.M. heterohybrid Ig in IEF gels, and we demonstrated the production of variant lambda L chains by the heterohybrid clones. One type of lambda L chain had a normal mobility in SDS-PAGE gels but larger lambda variants were produced by four of six heterohybrids. A Southern analysis of the VL gene displayed considerable variation in the type of lambda rearrangement present in the various heterohybrids, suggesting extensive diversity at the VL gene locus. In a second tumor (S.C.) that exhibited uniform anti-Id tumor reactivity we were also able to demonstrate the presence of a second minor tumor cell population (a biclonal tumor). Our data suggest that intraclonal VH variation may vary considerably with lymphoma subtype and mutagenic exposure and that an additional mechanism for generating spontaneous intraclonal heterogeneity is genetic variation at the VL locus.
Expression of murine IL-2 receptor beta-chain on thymic and splenic lymphocyte subpopulations as revealed by the IL-2-induced proliferative response in human IL-2 receptor alpha-chain transgenic mice.
Authors: Hattori M , Okazaki H , Ishida Y , Onuma M , Kano S , Honjo T , Minato N 
Published: December 2022

Abstract
Lymphocytes from the human (h) IL-2R alpha chain transgenic mice (TGM) constitutively express high affinity binding sites for hIL-2, consisting of transgenic h-IL-2R alpha and endogenous murine IL-2R beta, and therefore easily proliferate in vitro in response to hIL-2. Our study was undertaken to clarify the hIL-2-responsive lymphocyte subsets in the TGM, which should most likely reflect the normal distribution of m IL-2R beta expression. In both thymus and spleen, the majority of expanded cells by hIL-2 was CD3+CD4-CD8+ TCR alpha beta+ cells. The proliferation of CD4+ cells was not observed at all from either organ despite the expression of transgenic hIL-2R alpha. Potent cellular proliferation was also observed from the thymocytes that had been depleted of CD8+ cells, the expanded cells consisting of CD3- (15-40%) and CD3+ populations (60-85%). Among CD3+ cells, approximately the half portion expressed TCR alpha beta, whereas the other half was suggested to express TCR gamma delta. A variable portion (5-20%) of the CD3+ cells expressed CD8 (Lyt-2) in the absence of Lyt-3, and the CD3+CD8+ cells were confined preferentially to the TCR alpha beta- (TCR gamma delta+) population. In the culture of splenocytes depleted of CD8+ cells, however, the proliferated cells were mostly CD3-CD4-CD8-TCR-Mac1-, whereas a minor portion (10-30%) was CD3+CD4-CD8-TCR alpha beta- (TCR gamma delta+. Analysis of TCR genes at both DNA and mRNA levels confirmed the phenotypical observations. These results strongly suggested that IL-2R beta was constitutively and selectively expressed on the primary murine thymocytes and splenic T and NK cells, except for CD4+ cells in both organs.
The fine specificity of anti-La antibodies induced in mice by immunization with recombinant human La autoantigen.
Authors: St Clair E W , Kenan D , Burch J A , Keene J D , Pisetsky D S 
Published: December 2022

Abstract
Because of increasing evidence suggesting that anti-La autoantibodies are induced in humans by an Ag-specific mechanism, we investigated the antibody response of animals immunized with the human La Ag and studied its relationship to the anti-La response of autoimmune patients. Anti-La antibodies were raised in 6- to 8-wk-old male MRL(-)+/+, C57BL/6J, BALB/c, and A/J mice by immunizing with authentic human La protein obtained by recombinant expression in Escherichia coli. As we have shown previously for human autoantibodies, induced mouse anti-La antibodies reacted with recombinant fusion proteins containing nonoverlapping sequences from different portions of the La molecule. The epitope specificity of antibodies to the middle region of the La Ag was further evaluated using six synthetic La peptides predicted to be antigenic based on their hydrophilic properties. Although the induced mouse anti-La antibodies bound to five of the six synthetic La peptides, human anti-La autoantibodies failed to recognize any of the peptide homologs. These results suggest that mice respond to immunization with human La protein differently than humans who develop autoimmunity to this self Ag.
Platelet activation induces increased Fc gamma receptor expression.
Authors: McCrae K R , Shattil S J , Cines D B 
Published: December 2022

Abstract
Platelet contain Fc gamma RII. However, little is known about how the expression of these receptors is regulated. Inasmuch as platelet activation by a variety of agonists increases the expression of several proteins on the platelet surface, we used flow cytometry to study the effect of platelet activation on the expression of platelet Fc gamma R by measuring the binding of fluorescein-labeled oligomeric IgG (FITC-IgG oligomer) and fluorescein-labeled mAb IV.3 (FITC-IV.3), a mAb that recognizes Fc gamma RII, to platelets. The number of Fc gamma R per platelet was determined by relating the binding to platelets of FITC-IV.3, measured by flow cytometry, to the binding of 125I-labeled IV.3, measured using a standard filtration assay. Nonactivated, gel-filtered platelets from nine healthy donors expressed a mean of 891 Fc gamma R per platelet, whereas platelets activated at 25 degrees C by thrombin or PMA expressed a mean of 1382 Fc gamma R an average increase of 55% (p less than 0.001). Binding of FITC-IgG oligomer increased to a similar extent when platelets were stimulated by these agonists. A smaller increase in the number of Fc gamma R expressed on the platelet surface was measured when platelets were stimulated with ADP, though no increase was observed with epinephrine. The agonist-dependent increase in Fc gamma R expression did not occur when platelets were studied at 4 degrees C or in the presence of agents that elevate intracellular levels of cAMP, suggesting that platelet activation was required for this process. Agonist-stimulated Fc gamma R expression did not depend on dense-granule secretion, because it was observed at low agonist concentrations in the absence of 14C-serotonin release. These studies demonstrate that the number of Fc gamma R expressed on the platelet surface increases when platelets are activated by several agonists, perhaps as a result of the exposure of Fc gamma R located along the surface-connected open canalicular system, or the fusion of platelet alpha-granule and plasma membranes during the activation process. Increased Fc gamma R expression may promote the clearance of IgG-containing immune complexes from the circulation, and contribute to the development of immune complex-mediated thrombocytopenia.
Lipocortins are major substrates for protein kinase C in extracts of human neutrophils.
Authors: Stoehr S J , Smolen J E , Suchard S J 
Published: December 2022

Abstract
We have identified two major proteins in human neutrophils that are phosphorylated in vitro by protein kinase C (PKC) as lipocortins III and a fragment of a lipocortin-like 68-kDa protein. In electroporated cells, the 68-kDa protein was phosphorylated during stimulation of the cells with either FMLP or PMA. Lipocortins are of interest because of their Ca2(+)- and phospholipid-dependent actin binding properties and ability to inhibit phospholipase A2. Two crude fractions of enzymes and proteins exposed to [gamma-32]PATP in the presence of Ca2+, Mg2+, phosphatidylserine and 1,2-oleoyl-acetyl-rac-glycerol were analyzed by gel electrophoresis and autoradiography. A number of proteins in a detergent-free fraction, including proteins at 36 and 32 kDa, were phosphorylated in the presence of these cofactors. In contrast, only two major proteins (35 and 32 kDa) were phosphorylated in a detergent-extracted fraction. Phosphorylation of the 36, 35, and 32 kDa proteins required the presence of Ca2+, Mg2+, and phosphatidylserine in our soluble fraction and detergent extract, indicating PKC-dependent phosphorylation. The 32-kDa protein phosphorylated in both the soluble fraction and detergent extract was identified as lipocortin III by immunoprecipitation with a cross-reactive antibody that recognized lipocortin I and comparison of cyanogen bromide (CNBr) cleavage patterns of this protein with a lipocortin III standard. The 68-kDa protein was identified as a lipocortin VI-like protein by immunoprecipitation with anti-calelectrin. Additionally, the CNBr cleavage pattern of the 68-kDa protein was similar to that of the 36-kDa protein phosphorylated in our soluble fraction. Autoradiograms of the 68- and 36-kDa fragments immunoprecipitated from our soluble fraction with anticalelectrin and cleaved with CNBr showed that both of these proteins were phosphorylated in this sample. Because phosphorylation is known to change the functional characteristics of the lipocortins, the potential exists to link PKC and lipocortins in neutrophils to regulation of granulemembrane interactions or mediation of inflammation.
Estimation of D segment usage in initial D to JH joinings in a murine immature B cell line. Preferential usage of DFL16.1, the most 5' D segment and DQ52, the most JH-proximal D segment.
Authors: Tsukada S , Sugiyama H , Oka Y , Kishimoto S 
Published: December 2022

Abstract
We established SPL2-1-2, a murine immature B cell line transformed by tsOS-59, a temperature-sensitive mutant of Abelson murine leukemia virus. SPL2-1-2 has a VHDJH-/G (germ-line) configuration, and can continuously generate D to JH joinings from the germ-line allele during culture. The D to JH joinings are strongly promoted by the shift of the culture temperature from permissive (35 degrees C) to non-permissive temperature (39 degrees C). Using this H chain gene rearrangement system, we succeeded in the estimation of the frequencies of D segment usage in initial D to JH joinings by deletion-mapping analysis. The results demonstrated the preferential utilization of DFL16.1, the most 5' D segment and DQ52, the most JH-proximal D segment in initial D to JH joinings.
Roles of CD4+ and CD8+ T cells in murine contact sensitivity revealed by in vivo monoclonal antibody depletion.
Authors: Gocinski B L , Tigelaar R E 
Published: December 2022

Abstract
mAb specific for murine CD4+ and CD8+ T cell subsets were utilized to determine the populations participating in delayed-in-time, cutaneous hypersensitivity responses in BALB/c mice. In vivo depletions of these T cell phenotypes revealed that delayed-type hypersensitivity to cellular and protein Ag were mediated by CD4+ effector cells, whereas CD8+ cells down-regulated such responses. Similar depletions in mice prior to sensitization with the hapten 1-fluoro-2,4-dinitrobenzene demonstrated a more complex pattern of cell participation in contact sensitivity (CS) responses. Depletion of CD4+ cells resulted in strikingly enhanced ear swelling, indicating not only an important effector role for CD8+ cells but also a down-regulatory role for some CD4+ cells; depletion of CD8+ cells revealed that some CD4+ cells also act as CS effectors. In vitro depletion of immune lymph node cells with the same mAb before adoptive transfer confirmed CS effector roles for both subsets, and also suggested that at least some CD4+ suppressors act on the efferent limb of the CS response, perhaps by down-regulating the activity of CD8+ effector cells. Partial in vivo depletion with small amounts anti-CD4 mAb and subsequent flow cytometric analysis of residual CD4+ cells was consistent with the hypothesis that CD4+ CS effector cells express a higher density of the CD4 antigen than do CD4+ suppressor cells, raising the possibility that these two functionally distinct CD4+ populations might be separable on the basis of their surface expression of CD4.