bluuebunny/crossref_metadata_2025_split huggingface dataset:
IL-4 treatment of small splenic B cells induces costimulatory molecules B7-1 and B7-2.
Authors: Stack R M , Lenschow D J , Gray G S , Bluestone J A , Fitch F W 
Published: December 2022

Abstract
IL-4 has been shown to be involved in the early stages of B cell maturation. Changes induced by IL-4 include cell enlargement, increased viability, and increased MHC class II expression. However IL-4 alone does not induce B cell activation as defined by proliferation, lymphokine production, or Ig class switching. In this study, we demonstrate that incubation with IL-4 enhances the ability of small splenic murine B cells, normally poor stimulators of murine Th1 clones, to stimulate lymphokine production and proliferation by Th1 clones. Moreover, small resting B cells induce anergy, whereas IL-4-treated B cells do not. IL-4-treated B cells were found to express both B7 (B7-1) and a second ligand for CTLA4Ig (B7-2). Although IL-4 induces both B7-1 and B7-2, the kinetics of expression of these molecules are different: B7-2 is detected by 6 h, whereas B7-1 is not detectable until 48 h. In addition, only CTLA4Ig fully blocks IL-4 induced costimulatory activity; a mAb to B7-1 does not. Thus, these results suggest that IL-4 may function indirectly as a costimulatory factor by inducing costimulatory molecules on resting B cells. Additionally, these findings support our previous findings that an alternative ligand for CD28 and CTLA4 is important in providing costimulation.
HLA-DR3 molecules can bind peptides carrying two alternative specific submotifs.
Authors: Geluk A , van Meijgaarden K E , Southwood S , Oseroff C , Drijfhout J W , de Vries R R , Ottenhoff T H , Sette A 
Published: December 2022

Abstract
Three different HLA-DR3-specific peptide binding motifs have been proposed. These motifs shared a major hydrophobic anchor at the N-terminus, but differed in the C-terminal anchor residues. In the present study, the structural requirements for peptide binding to HLA-DR3 were examined in further detail by using quantitative HLA-DR3-specific binding assays and sets of single substitution analogues of DR3 binding peptides (Lol pollen amino acids 171-190 and sperm whale myoglobin amino acids 132-151). We found that the requirements for binding to HLA-DR3 vary among different DR3 binding peptides; the absence of an anchor or the presence of only a weak anchor residue at either position n or n + 3 can be compensated for by the presence of a strong, positively charged anchor residue at position n + 5. These results explain several of the previously reported differences between DR3-specific peptide binding motifs. To evaluate the predictive value of the thus-refined motif, the DR3 binding capacity of an overlapping set of peptides, spanning the entire sequence of the 65-kDa heat shock protein of Mycobacterium tuberculosis was investigated and correlated with the occurrence of the different DR3 motifs. A strong correlation was found between the presence of the refined DR3 motif and peptide binding to purified HLA-DR3 molecules.
Nitric oxide production by splenic macrophages is not responsible for T cell suppression during acute infection with lactate dehydrogenase-elevating virus.
Authors: Rowland R R , Butz E A , Plagemann P G 
Published: December 2022

Abstract
Cellular immune responses of mice are transiently suppressed during acute infection with lactate dehydrogenase-elevating virus (LDV). Immunosuppression of mice correlated with a greatly impaired in vitro proliferative response of the majority of the T cells to Con A or anti-CD3 Abs, which could not be reversed by the addition of rIL-2. We have examined whether the T cell suppression is caused by nitric oxide (NO) produced by activated macrophages, which are observed in acutely infected mice. Spleen macrophages from 3-day LDV-infected mice exhibited a 6- to 10-fold increased potential for producing NO, measured as nitrite or nitrite plus nitrate in the culture fluid, but produced significant amounts of NO in vitro only when incubated with IFN-gamma produced by Con A-stimulated T cells in the spleen cell population. Furthermore, we found that the concentrations of NO produced by macrophages in cultures of spleen cells from LDV-infected mice in the presence of IFN-gamma were insufficient to cause a reduction in the proliferative response of T cells in the spleen cell population. An excess of activated macrophages had to be added to achieve T cell suppression. NO inhibition of Con A-induced T cell proliferation exhibited a very sharp dose-response curve. In one experiment little suppression was observed at NO concentrations equivalent to 12 microM nitrite and below, whereas almost complete inhibition was observed at twice the NO concentration. We conclude that NO is not responsible for T cell suppression in LDV-infected mice.
Use of N-acetyl cysteine to increase intracellular glutathione during the induction of antitumor responses by IL-2.
Authors: Yim C Y , Hibbs J B , McGregor J R , Galinsky R E , Samlowski W E 
Published: December 2022

Abstract
IL-2 therapy can induce marked oxidative stress via reactive oxygen and nitrogen intermediates. Glutathione, the major intracellular reductant, may become rate limiting to cytotoxic lymphocyte activation and proliferation under these circumstances. N-Acetyl cysteine (NAc-cys) was used to increase intracellular glutathione levels during lymphokine-activated killer (LAK) cell activation by IL-2. Incubation of splenocytes with NAc-cys (0.6 to 1.0 mM) resulted in significant changes in intracellular reduced and total glutathione (92% and 58% increase, respectively) at 96 h. These levels correlated with markedly enhanced cell proliferation (threefold) and cytolytic effector cell generation (&gt; fivefold increase in LU/10(6) cells) induced by the combination of NAc-cys with IL-2. IL-2 exposure by itself unexpectedly increased intracellular reduced glutathione by 43%. IL-2 and NAc-cys were synergistic in increasing glutathione levels (reduced glutathione: 292% increase; total: 251% increase). Inhibition of glutathione synthesis, using L-buthionine-(S,R)-sulfoximine reversed the effects of NAc-cys on intracellular glutathione, as well as cellular proliferation and cytotoxicity. This experiment established that the effects of NAc-cys required de novo glutathione synthesis. In conjunction with IL-2/LAK treatment, oral NAc-cys administration (260 to 900 mg/kg/day for 7 days) significantly decreased tumor progression in a refractory s.c. tumor model. A small fraction of mice (11 to 17%) had complete tumor regressions. NAc-cys may be useful as an adjunct to increase the antitumor activity of IL-2/LAK therapy.
In vivo and in vitro functional examination of a conserved epitope of L- and E-selectin crucial for leukocyte-endothelial cell interactions.
Authors: Bargatze R F , Kurk S , Watts G , Kishimoto T K , Speer C A , Jutila M A 
Published: December 2022

Abstract
Selectins constitute a three-member gene family of carbohydrate-binding adhesion proteins found on the surface of leukocytes and endothelial cells that is central to inflammation-associated leukocyte recruitment and lymphocyte recirculation. E- and P-selectin are inducible and expressed on the surface of endothelial cells under inflammatory conditions, whereas L-selectin is constitutively expressed on most circulating leukocytes. Previously, we have characterized a unique mAb (EL-246) that recognizes a common epitope on both E- and L-selectin, which is presented or determined by their short consensus repeat domains. This report defines the functional properties of EL-246 and its cognate epitope. In a novel in vitro physiologic shear system, we show that neutrophil rolling on activated HUVECs and on E-selectin cDNA transfectants is blocked 45 to 120 s after infusion of EL-246. The examination of the binding of neutrophils to E-selectin cDNA transfectants reveals that their adhesion is blocked by EL-246 treatment of either cell type. A unique Ab transfer mechanism is demonstrated in which El-246 is delivered unidirectionally from L- to E-selectin to surpass the adhesion blocked by mAbs that recognize either L- or E-selectin alone. By using flow cytometry and in vivo homing techniques, we show that pretreating bovine lymphocytes with EL-246 blocks their ability to home to mouse peripheral lymph nodes by &gt; 65%. Cumulatively, these results suggest that EL-246 is a uniquely potent pharmacologic inhibitor of leukocyte-endothelial cell interactions that are mediated by either E- or L-selectin.
Substrate specificities of murine C1s.
Authors: Ogata R T , Low P J , Bradt B M , Cooper N R 
Published: December 2022

Abstract
An early step in the initiation of the classical C pathway is the proteolytic activation of component C4 by subcomponent C1-s. We have examined the substrate specificity of murine C1-s (mC1-s) by measuring its proteolytic activity on human and murine C4, and on the murine C4 isotype designated sex-limited protein (Slp). The latter substrate was examined because previous studies have demonstrated that Slp is not cleaved by C1-s, and hence Slp has been assumed to be nonfunctional in the C pathways. Those earlier studies used human, not murine, C1-s, however; a recent report has suggested that Slp is an essential component of a novel complement activation pathway and that the previous failure to observe cleavage of Slp is probably the result of a species incompatibility between Slp and the heterologous human C1-s (hC1-s). The present studies do not support this idea, as we found no evidence of cleavage of Slp by homologous murine C1-s even at enzyme concentrations 10-fold higher than that necessary for 50% cleavage of murine C4 (mC4). We did find a species-specific affect in the cleavage of mC4, where mC1-s is about 10-fold more effective than heterologous hC1-s in cleaving mC4, but mC1-s itself does not distinguish between human and murine C4, cleaving both equally well. Hence mC1-s does not exhibit the species specificity previously found for hC1-s, which shows a several hundred-fold preference for homologous human C4 over murine C4.
Increased TGF-beta and decreased oncogene expression by omega-3 fatty acids in the spleen delays onset of autoimmune disease in B/W mice.
Authors: Fernandes G , Bysani C , Venkatraman J T , Tomar V , Zhao W 
Published: December 2022

Abstract
This study was designed to investigate the mechanisms by which marine lipids rich in long chain omega-3 fatty acids inhibit autoimmune disease and prolong the survival rate in female (NZB/NZW) F1 (B/W) mice, an animal model for human SLE. Nutritionally adequate semipurified diets containing at 10% either corn oil (CO) or fish oil (FO) were fed from 1 mo of age and were monitored for proteinuria and survival. Proteinuria was detected earlier and became progressively severe in CO-fed mice. The average life span was significantly shortened by the CO diet (266.7 days +/- 12.5), whereas FO extended the survival significantly (402.1 days +/- 26.1; p &lt; 0.001). A cross-sectional study at 6.5 mo of age revealed an increased proliferative response to T cell mitogens including bacterial superantigens and decreased serum anti-dsDNA Ab titers in the FO group compared with the CO group. Furthermore, splenocytes from the FO group when stimulated with Con A had higher IL-2 and lower IL-4 production similar to that of young (3.5 mo) mice. Flow cytometric analyses of splenocytes revealed lower Ig+, higher lymphocyte endothelial cell adhesion molecule-1, and lower Pgp-1+ cells within CD4+ and CD8+ subsets in FO-fed mice. Also, elevated IL-2 and IL-4 and significantly higher TGF-beta 1 and lower c-myc and c-ras mRNA expression and higher TGF-beta 1 and significantly lower c-Myc and c-Ha-Ras proteins were detected in spleens of FO-fed mice. Fatty acid analysis revealed significantly higher linoleic (18:2 omega-6) and arachidonic (20:4 omega-6) acid levels in splenocytes of the CO-fed group and higher eicosapentaenoic (20:5 omega-3) and docosahexanoic (22:6 omega-3) acid levels in the FO-fed group, indicating that changes in membrane fatty acid composition may contribute to the altered immune function and gene expression during the development of murine SLE.
Defective production of anti-inflammatory cytokine, TGF-beta by T cell lines of patients with active multiple sclerosis.
Authors: Mokhtarian F , Shi Y , Shirazian D , Morgante L , Miller A , Grob D 
Published: December 2022

Abstract
Activated T lymphocytes play an important role in the pathogenesis of multiple sclerosis (MS). These T cells secrete both pro- and anti-inflammatory cytokines. We have studied the production of these two kinds of cytokines by PBL of patients with MS and compared it with normal controls and other autoimmune diseases (OAD). PBL of 29 patients with MS, 14 patients with OAD, and 14 healthy normal controls were cultured for 5 wk. PBL of MS patients produced more pro-inflammatory cytokines, IL-2, IFN-gamma and TNF/lymphotoxin, and less anti-inflammatory cytokine, TGF-beta, during wk 2 to 4 in culture than PBL of normal controls. PBL of MS patients also produced more IL-2 and TNF/lymphotoxin than PBL of OAD patients. Decreased TGF-beta production by lymphocytes of patients with MS correlated directly with disease activity. MS patients with active disease produced less TGF-beta than MS patients with stable disease. The cells producing TGF-beta were primarily CD8+ T cells and CD45RA+T cells. These findings emphasize the complexity of immune response in MS patients and suggest that the increased production of pro-inflammatory cytokines by lymphocytes of patients with MS, combined with the decreased production of TGF-beta (anti-inflammatory cytokine), may play an important role in the mechanisms and manifestations of MS.
T-B collaboration for autoantibody production in lpr mice is cognate and MHC-restricted.
Authors: Sobel E S , Kakkanaiah V N , Kakkanaiah M , Cheek R L , Cohen P L , Eisenberg R A 
Published: December 2022

Abstract
A central question in autoimmunity is the mechanism of T cell help for autoantibody production. For responses to exogenous Ag, T-B collaboration is restricted by MHC class II molecules. To determine whether T cell help that leads to autoantibodies in murine SLE is also MHC-restricted, we have constructed bone marrow chimeras with Ig heavy chain (lgh) allotype- and I-A-congenic donor B6/lpr mice and I-A-congenic recipients. Developing T cells were thus positively selected in the host thymus to interact with B cells bearing I-A of one haplotype or the other. Additional control host mice were heterozygous for I-A expression, allowing T helper cell selection for both I-A haplotypes. Five months after reconstitution, serum total IgG2a, IgM, IgG2a antichromatin, and IgM rheumatoid factor were quantitated by allotype-specific ELISA. Data showed that whereas substantial numbers of B cells were present from both donor strains in all mice, autoantibody production was overwhelmingly from those donor B cells expressing the same I-A haplotype as the host. Sera from the I-A heterozygous control recipient group had roughly equal quantities of autoantibodies of both allotypes, as expected. The finding of MHC class II restriction implies that the T cell help that drives autoantibody production in lpr mice is delivered through cognate (cell-to-cell) interactions and not by soluble factors alone.
T cell activation results in physical modification of the mouse CD8 beta chain.
Authors: Casabó L G , Mamalaki C , Kioussis D , Zamoyska R 
Published: December 2022

Abstract
The T lymphocyte glycoprotein, CD8, is an essential component of the response of class I MHC-restricted T cells to Ag. CD8 is expressed on the surface of class I-restricted T cells as disulfide-bonded heterodimers and higher multimers of two distantly related polypeptides, alpha and beta. The CD8 alpha polypeptide, expressed in transfection studies as homodimers, is able to reproduce both the adhesive and stimulatory properties of CD8, leaving the function of the CD8 beta polypeptide unresolved. Herein we demonstrate that the CD8 beta polypeptide changes physically during T cell maturation and activation by reversibly altering its sialic acid content. These changes occur specifically on CD8 beta not -alpha, indicating that the primary role of the CD8 beta chain may be regulatory, influencing the physical structure of the CD8 complex, and suggesting a novel mechanism of controlling receptor/ligand interactions.
Ligation of CD40 induces sterile transcripts of multiple Ig H chain isotypes in human B cells.
Authors: Jumper M D , Splawski J B , Lipsky P E , Meek K 
Published: December 2022

Abstract
Stimulation of human B cells with mAb to CD40 in the presence of IL-4 induces proliferation and differentiation into Ig-secreting cells. To delineate the molecular events leading to Ig secretion after stimulation via the CD40 molecule, the induction of germ-line transcripts of Ig H chain isotypes was analyzed by polymerase chain reaction. The results document that costimulation with mAb to CD40 and IL-4 induces sterile transcription of all Ig H chain isotypes. Of importance, stimulation with mAb to CD40 without the addition of IL-4 induced germ-line transcription of most downstream isotypes, suggesting that this signal is sufficient to initiate the first step in switch recombination.
Inducible binding of human lymphocytes to hyaluronate via CD44 does not require cytoskeleton association but does require new protein synthesis.
Authors: Murakami S , Shimabukuro Y , Miki Y , Saho T , Hino E , Kasai D , Nozaki T , Kusumoto Y , Okada H 
Published: December 2022

Abstract
We have examined molecular mechanisms of the PMA-inducible HA binding ability of human lymphocytes. Newly established OS/6 and OS/37, specific for human CD44, specifically inhibited PMA-induced HA binding of several human cell lines, suggesting that both mAb detect HA binding epitope(s) on CD44. Sequential staining revealed that these mAb cross-blocked each other's binding to Molt-4, T lymphoblast lines, and that neither of them interfered with staining of Molt-4 by other anti-CD44 mAb which induced significant homotypic cell aggregation. Biochemical and PCR analyses did not provide any evidence that PMA stimulation induced dramatic changes in molecular weight or molecular isoforms of CD44. Interestingly, HA binding was not affected and rather slightly increased by cytochalasin B which disrupts F-actin microfilament integrity. This suggests that the ability of CD44 to bind to HA does not correlate with the association of CD44 with the cytoskeleton. On the other hand, protein synthesis inhibitors, cycloheximide and anisomycin clearly inhibited the induction of HA binding of PMA-activated Molt-4 without affecting the expression of CD44 at the same time after stimulation. The same treatment had no effect on PMA-induced FN binding of the cells, which was mediated by VLA integrins. These results suggest that the adhesion functions of CD44 and integrins are differently regulated despite the fact that both are induced by PMA stimulation, and that new protein synthesis is essential for the PMA-induced HA binding by CD44.
Autocrine stimulation of B lymphocytes by a platelet-activating factor receptor agonist, 1-palmitoyl-2-acetyl-sn-glycero-3-phosphocholine.
Authors: Tordai A , Franklin R A , Johnson C , Mazer B D , Clay K L , Gelfand E W 
Published: December 2022

Abstract
Based on previous data which demonstrated the ability of platelet-activating factor (PAF) antagonists to inhibit constitutive immunoglobulin synthesis in B-lymphoblastoid cell lines, we determined the capacity of these cells to synthesize PAF or 1-palmitoyl-2-acetyl-sn-glycero-phosphocholine (PAGPC), an acyl-PAF identified in various cell types. In two B-lymphoblastoid cell lines (LA350 and HSCE-), significant amounts of production of PAGPC were detected, whereas the amount of PAF was below the level of detection in our system. The biologic effects of PAGPC were examined in these cells, both of which have well-characterized PAF receptors. PAGPC induced a concentration-dependent increase in intracellular Ca2+ concentrations and activation of MAP-2 kinase (as detected by immunoblotting and measurements of kinase activity) in these cells. The kinetics and magnitude of these responses were similar to those induced by PAF, and they were inhibited by Web 2086, a PAFR antagonist. Phosphatidylcholine, which differs from PAGPC in that it contains a long fatty acid residue at position 2, did not induce any of these responses. A mutual cross-desensitization of the B lymphoblasts between PAGPC and PAF was observed for Ca2+ mobilization. To induce maximal cell stimulation, approximately 600-fold higher concentrations of PAGPC than of PAF were needed. Because the two B-lymphoblastoid cell lines synthesized significant amounts of PAGPC, this phospholipid may participate in an autocrine stimulation pathway in B cells. Furthermore, the data indicate that PAGPC is an agonist for the PAFR in B lymphoblasts and that the ether linkage in the PAF molecule is not an absolute requirement for activity, although it increases the potency of the ligand.
Identification of a protein, SPY75, with repetitive helix-turn-helix motifs and an SH3 domain as a major substrate for protein tyrosine kinase(s) activated by Fc epsilon RI cross-linking.
Authors: Fukamachi H , Yamada N , Miura T , Kato T , Ishikawa M , Gulbins E , Altman A , Kawakami Y , Kawakami T 
Published: December 2022

Abstract
Cross-linking of the high affinity receptor for IgE (Fc epsilon RI) initiates various biochemical and morphologic changes leading to degranulation and synthesis and release of cytokines and lipid mediators. Tyrosine phosphorylation of several cellular proteins was previously reported as the earliest signaling event for the Fc epsilon RI signal transduction pathway. By amino acid sequence determination and cDNA cloning analysis, a 75-kDa protein, termed SPY75, was identified as a major tyrosine-phosphorylated protein in activated mouse mast cells. SPY75, barely tyrosine phosphorylated in resting cells, was rapidly and transiently tyrosine phosphorylated on Fc epsilon RI cross-linking in an Ag concentration-dependent manner. Similar SPY75 tyrosine phosphorylation was observed when Ag receptors on B and T lymphocytes were cross-linked by appropriate antibodies. However, IL-3, granulocyte macrophage-CSF, or stem cell factor did not induce tyrosine phosphorylation of SPY75 in PT-18 mast cells, despite their responsiveness to these cytokines. SPY75 was not physically associated with the receptor or other known signaling molecules. This protein, the mouse homologue of the human HS1 gene product, has putative repetitive helix-turn-helix motifs found in many DNA-binding proteins and a putative nuclear transport signal. It also has a Src homology 3 domain, which is found in many signaling molecules and cytoskeletal proteins. These structural features and the rapid tyrosine phosphorylation on Fc epsilon RI cross-linking suggest that the signal generated by Fc epsilon RI cross-linking is transmitted through tyrosine phosphorylation of SPY75.