bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tolerance induction in resting memory B cells specific for a protein antigen.
Authors: Johnson J G , Jemmerson R 
Published: December 2022

Abstract
Resting memory B lymphocytes specific for the model protein Ag cytochrome c have been shown to be susceptible to tolerance induction in in vitro splenic fragment cultures. This induction of nonresponsiveness is dependent upon the strength of the interaction between surface Ig and specific Ag, where concentration, valency, affinity, and time of exposure all appear to be important factors, as is the case for tolerance induction in immature or primary B cells. The induction of nonresponsivenes in greater than 80% of Ag-specific memory B cells was achieved by incubation with 1 microM cytochrome polymer for 24 h in the absence of T cell help. Not only were memory B cells unresponsive to specific Ag, they were also unable to become activated through nonspecific uptake and presentation of an Ag to which T cells have been primed, demonstrating that the induction of nonresponsiveness involves more than a modulation or blockade of surface Ig receptors. Although soluble factors collected from activated T cells failed to prevent memory B cells from becoming nonresponsive after surface Ig cross-linking, the direct activation of T cells within splenic fragment cultures did partially inhibit tolerance induction in splenic fragment memory B cells. In addition, the induction of tolerance was partially blocked by protein tyrosine kinase inhibitors, suggesting a physiologic change within the B cells associated with the state of nonresponsiveness and resulting from tyrosine-specific phosphorylation.
Humanized OKT3 antibodies: successful transfer of immune modulating properties and idiotype expression.
Authors: Woodle E S , Thistlethwaite J R , Jolliffe L K , Zivin R A , Collins A , Adair J R , Bodmer M , Athwal D , Alegre M L , Bluestone J A 
Published: December 2022

Abstract
Antibodies that possess the Ag-binding regions of OKT3 within the context of a human framework (Hu-OKT3 Ab) offer distinct advantages for optimizing anti-CD3 mAb therapy. First, manipulation of Ab genes to produce humanized Ab that retain Ag-binding activity may circumvent antigenicity problems. Second, Ab gene engineering provides a means for modifying functional properties, including T cell activation and immune suppression. The purpose of this study was to determine the functional properties of Hu-OKT3 Ab and to compare the functional properties and idiotypes of Hu-OKT3 Ab to those of murine OKT3. Three Hu-OKT3 IgG4 Ab, a chimeric OKT3 antibody (cOKT3-1) (grafted sequences comprising all OKT3 VH and VL regions) and two complementarity determining region (CDR)-grafted antibodies, gOKT3-5 and gOKT3-6 (grafted sequences comprising only OKT3 VH and VL CDR and some framework amino acids, were analyzed. Initial studies demonstrated that the cOKT3 and gOKT3-5 Ab bound selectively to T cells and competitively inhibited OKT3-FITC binding with avidities similar to that of murine OKT3. Binding avidity of the gOKT3-6 Ab was markedly less than that of the other two Hu-OKT3 Ab. Serologic analysis suggested that cOKT3 and gOKT3-5 Ab possess idiotypes (combining sites) similar to murine OKT3. T cell activation potency of all three Hu-OKT3 Ab was assessed by proliferation, induction of activation marker expression (IL-2R and Leu 23), and lymphokine production (TNF-alpha and IFN-gamma). The cOKT3 and gOKT3-5 Ab demonstrated T cell activation potencies similar to murine OKT3 as assessed by each parameter. CD3 coating and modulation by these two Ab was effective but somewhat less potent than that observed with OKT3. Finally, cOKT3 and gOKT3-5 Ab both inhibited CTL activity comparably to murine OKT3. In conclusion, these studies indicate that gOKT3-5 and cOKT3 Ab possess immune modulating properties similar to murine OKT3 and thus offer attractive alternatives to murine OKT3 for in vivo therapy.
A nuclear DNA-binding protein expressed during early stages of B cell differentiation interacts with diverse segments within and 3' of the Ig H chain gene cluster.
Authors: Liao F , Giannini S L , Birshtein B K 
Published: December 2022

Abstract
We have used electrophoretic mobility shift assays (EMSA) to detect B cell lineage-specific nuclear proteins that bind to diverse segments within and 3' of the Ig H chain gene cluster. DNA binding sites include sequences 5' of each of the following C region genes: mu, gamma 1, gamma 2a, epsilon, and alpha. For the most part, these binding sites lie 5' of CH-associated tandem repeats. Binding sites for the same B cell lineage-specific proteins have also been defined in the region 3' of C alpha, close to a recently described B cell-specific enhancer element. Cross-competition of EMSA indicates that the B cell lineage-specific nucleoprotein is indistinguishable from those described previously by others: S alpha-BP and BSAP. Because of the diverse sequences recognized by this protein, we term it NF-HB, B-lineage-specific nuclear factor that binds to Ig H gene segments. EMSA using segments 5' of S gamma 2a (5'S gamma 2a-176) and 3' of C alpha (3' alpha-88) shows multiple binding complexes, two of which are B cell lineage specific. The B cell-specific complex with fastest mobility contains only NF-HB, and the one with slowest mobility contains NF-HB together with a ubiquitous DNA-binding protein(s). The ubiquitous binding protein is different for 5' S gamma 2a-176 and for 3' alpha-88, representing the formation of protein-NF-HB complexes specific for these particular Ig DNA regions. Spleen cells show a single band upon EMSA with either 5'S gamma 2a-176 or 3' alpha-88. Upon LPS stimulation, additional binding complexes of slower mobility were formed resulting in a pattern comparable to those detected in pro-B, pre-B, and B cell lines. We hypothesize that NF-HB may promote physical interactions between the 3' alpha-enhancer and segments of the Ig H gene cluster.
Mapping of human H chain V region genes (VH4) using deletional analysis and pulsed field gel electrophoresis.
Authors: Van Dijk K W , Milner L A , Milner E C 
Published: December 2022

Abstract
We have used molecular genetic mapping techniques to establish the order and approximate chromosomal locations of VH4 elements on both chromosomes 14 from a single patient. A total of 10 BglII restriction fragments carrying VH4 elements was characterized. The genomic order of VH4-carrying restriction fragments was determined by analysis of the pattern of loss of hybridizing bands from the genomes of a panel of monoclonal lymphoblastoid cell lines which had well characterized rearrangements of the Ig locus on each chromosome. Some individual elements were identified using sequence-specific oligonucleotide probes. Physical dimensions were estimated by the assignment of these ordered elements to large (50-350-kb) restriction fragments using two-dimensional pulse field gel electrophoresis. Six such fragments spanning approximately 890 kb were physically linked and ordered. The chromosomes differed with respect to the complement of VH4 elements, although no evidence was found of major differences in organization. The establishment of a panel of well characterized deletion lines facilitates the rapid mapping of defined restriction fragments carrying VH elements.
Regulation of rat pulmonary artery endothelial cell transforming growth factor-beta production by IL-1 beta and tumor necrosis factor-alpha.
Authors: Phan S H , Gharaee-Kermani M , McGarry B , Kunkel S L , Wolber F W 
Published: December 2022

Abstract
Recent studies suggest that transforming growth factor-beta (TGF-beta) production is up-regulated at sites of tissue injury, inflammation and repair, or fibrosis. Endothelial cells represent a potentially important in vivo source of TGF-beta; however, the identity of endogenous modulators of TGF-beta production by these cells remains unclear. To address this issue, the effects of the cytokines, IL-1 beta, and TNF-alpha on TGF-beta production by rat pulmonary artery endothelial cells were examined. Conditioned media from cells treated with 0 to 20 ng/ml IL-1 beta and/or TNF-alpha were assayed for TGF-beta activity using a mink lung epithelial cell line. The results show that rat pulmonary artery endothelial cells secreted undetectable amounts of active TGF-beta in the absence of cytokines. However, upon acidification of the conditioned media before assay, a time-dependent increase in TGF-beta activity was noted in media from both untreated and cytokine-treated cells. However, both IL-1 beta and TNF-alpha treatment caused the secretion of significantly greater amounts of TGF-beta activity than control cells, in a dose-dependent manner, with maximal response obtained at cytokine doses of greater than 10 ng/ml. At equivalent doses of cytokine tested, the magnitude of the response was significantly greater with IL-1 beta. These responses were paralleled by increases in steady state mRNA levels for TGF-beta 1. Addition of both cytokines resulted in a synergistic response. Synergism with IL-1 beta was also noted with the fibrogenic agent bleomycin. Kinetic studies indicated that a minimum of 4 h of treatment with either IL-1 beta or TNF-alpha was required for detection of significant increases in either secreted TGF-beta activity or steady state TGF-beta 1 mRNA levels. Thus, endothelial cells could play a role in various TGF-beta-dependent processes in vivo, in situations wherein IL-1 beta and/or TNF-alpha may be present at comparable concentrations.
Species specificity in the interaction of CD8 with the alpha 3 domain of MHC class I molecules.
Authors: Newberg M H , Ridge J P , Vining D R , Salter R D , Engelhard V H 
Published: December 2022

Abstract
The alpha 1 and alpha 2 domains of the class I MHC molecule constitute the putative binding site for processed peptides and the TCR, although the alpha 3 domain has been implicated as a binding site for the CD8 molecule. Species specificity in the binding of CD8 to the alpha 3 domain has been suggested as an explanation for the low xenogeneic T cell response to class I molecules, but results on this point have been conflicting and controversial. We have addressed this issue using CTL lines from HLA-A2.1 transgenic mice that specifically recognize and lyse A2.1-expressing cells infected with influenza A/PR/8 or pulsed with influenza matrix peptide M1(57-68). Species specificity was examined using transfectants that expressed hybrid molecules containing the alpha 1 and alpha 2 domains from HLA-A2.1 and the alpha 3 domain from a murine class I molecule. Lower levels of M1(57-68) peptide were required to sensitize L cell transfectants expressing a chimera that contained an H-2Dd alpha 3 domain than targets expressing the intact A2.1 molecule. However, at high doses of peptide, lysis of these two targets was similar. However, no reproducible difference in sensitization was observed using EL4 or Jurkat transfectants expressing A2.1 or A2.1 chimeric molecules that contained an H-2Kb alpha 3 domain. In all cases, however, lysis of peptide-pulsed A2.1 expressing targets was more sensitive to inhibition with anti-CD8 mAb than lysis of cells expressing these chimeric molecules. Thus, under suboptimal conditions such as low Ag density or in the presence of anti-CD8 mAb, these CTL preferentially recognize class I molecules with a murine alpha 3 domain. This suggests that there is some species specificity in the interaction of CD8 with the alpha 3 domain of the class I molecule. However, CTL recognition was inhibited by point mutations in the alpha 3 domain of HLA-A2.1 that have been shown to inhibit binding of human CD8 and recognition by human CTL, suggesting that murine CD8 interacts to some degree with human alpha 3 domains, and that similar alpha 3 domain residues may be important for murine and human CD8 binding. The relevance of these results to an understanding of low xenogeneic responses is discussed.
Mechanisms of lipopolysaccharide-induced neutrophil retention. Relative contributions of adhesive and cellular mechanical properties.
Authors: Erzurum S C , Downey G P , Doherty D E , Schwab B , Elson E L , Worthen G S 
Published: December 2022

Abstract
Intravascular LPS rapidly induces neutrophil sequestration in pulmonary capillaries by mechanisms that, although currently unknown, must take into account the size difference between the neutrophil and capillary diameter. To determine whether LPS alters neutrophil stiffness, and hence the ability of neutrophils to traverse capillaries, neutrophil passage through pulmonary capillaries was modeled by passage through filters with 6.5-microns pores. LPS increased retention in the pores in a concentration-dependent fashion that required the presence of heat-inactivated platelet-poor plasma, and was evident as early as 10 min after stimulation. The effect of LPS on the structural properties of the neutrophil was then studied. LPS induced f-actin reorganization in neutrophils in the presence of plasma. Disruption of actin organization and assembly with cytochalasin D completely inhibited early LPS-induced retention and attenuated retention at later timepoints, indicating that LPS-stimulated retention depends on filament organization. LPS-induced actin assembly and retention were abrogated by an antibody directed against CD14, a putative LPS receptor. CD18-dependent adherence of neutrophils contributed significantly to retention only at later timepoints with no significant contribution to retention at 20 min as determined by inhibition of adherence with the mAb 60.3. Morphometric assessment of neutrophil accumulation in the lungs of rabbits given 1 microgram LPS showed a marked increase in apparent neutrophil number, which was unaltered by antibodies to CD18, suggesting that mechanisms other than adhesion may account for accumulation in vivo. Direct measurements showed that neutrophil stiffness increased with exposure to LPS in a fashion similar to LPS-induced retention and actin organization. Pretreatment of neutrophils with cytochalasin D attenuated the increased stiffness. These data suggest that reorganization of filamentous-actin induced by LPS leads to cell stiffening and retention in capillary-sized pores. Although the organization of f-actin continues to be important in retention at later time points, adherence of cells also contributes significantly to cell retention. The changes in mechanical properties of the neutrophil may be important in the sequestration of neutrophils in pulmonary capillaries noted in endotoxemia.
Expression of the murine homologue of the cell cycle control protein p34cdc2 in T lymphocytes.
Authors: Kim Y H , Proust J J , Buchholz M J , Chrest F J , Nordin A A 
Published: December 2022

Abstract
The mammalian homologue of the cdc2 gene of the fission yeast Schizosaccharomyces pombe encodes a p34cdc2 cyclin-dependent kinase that regulates the cell cycle of a wide variety of cell types. Resting murine T lymphocytes contained no detectable p34cdc2 protein, histone kinase activity, or specific mRNA for the cdc2 gene. Activation of the T cells by immobilized anti-CD3 resulted in the expression of specific mRNA late in the G1 phase of the cell cycle, and p34cdc2 protein was detectable at or near G1/S. At this point in the cell cycle, the protein was phosphorylated at tyrosine and displayed no H1 histone kinase activity. As the cells progressed through the cycle, the amount of specific mRNA and p34cdc2 increased, and H1 histone kinase activity was detectable when the cells were blocked at G2/M by nocodazole. The activation of T cells by phorbol dibutyrate induced the expression of IL-2R but failed to induce the synthesis of IL-2 or the expression of cdc2-specific mRNA. Under these conditions, the activated cells failed to enter the S phase of the cell cycle. Because the presence of IL-2 added exogenously during activation by phorbol dibutyrate resulted in the expression of cdc2-specific mRNA and progression through the cell cycle, either IL-2 or the interaction with IL-2R may be involved in the expression of cdc2 and regulation of the G1/S transition.
Modulatory effects of Epstein-Barr, herpes simplex, and human herpes-6 viral infections and coinfections on cytokine synthesis. A comparative study.
Authors: Gosselin J , Flamand L , D'Addario M , Hiscott J , Stefanescu I , Ablashi D V , Gallo R C , Menezes J 
Published: December 2022

Abstract
Herpesviruses such as EBV, HSV, and human herpes virus-6 (HHV-6) have a marked tropism for cells of the immune system and therefore infection by these viruses may result in alterations of immune functions, leading at times to a state of immunosuppression. We report the results of a comparative study in which we found that EBV, HSV-1, and HHV-6 act differentially on the immune system with regard to their effect on the synthesis of IL-1 beta, IL-6, and TNF-alpha, i.e., three immunoregulatory cytokines mainly secreted by activated monocytes/macrophages. Using the polymerase chain reaction technique, analyses of the mRNA levels for each of the three monokines after viral infection indicated that the effect exerted by each of these herpesviruses on cytokine synthesis by human PBMC was detectable at the transcriptional level. Different amounts of IL-1 beta protein were detected in infected PBMC cultures, HHV-6 being the strongest IL-1 beta up-regulatory among these three herpesviruses. Spontaneous releases of IL-6 and TNF-alpha were found reduced after infection by HHV-6 and EBV, respectively. In comparison to EBV and HHV-6, HSV-1 proved to be a weak monokine enhancer. Results of coinfection studies indicated that virus-induced suppressive effects on cytokine synthesis are dominant. In fact, EBV inhibited TNF-alpha synthesis even in the presence of HHV-6, a strong up-regulator of TNF-alpha synthesis. Similarly, EBV was unable to stimulate IL-6 production in the presence of HHV-6. Viral structural component(s) appeared to be responsible for the up-regulation of IL-6 by both EBV and HSV-1, and of TNF-alpha by HSV-1. Taken together, our observations illustrate that herpesviruses can selectively regulate cytokine synthesis thereby disturbing immune homeostasis; this effect may favor pathogenic events, including the reactivation and/or spread of other infectious agents within the host.
IL-4 inhibits macrophage-mediated killing of Plasmodium falciparum in vitro. A possible parasite-immune evasion mechanism.
Authors: Kumaratilake L M , Ferrante A 
Published: December 2022

Abstract
Although a number of mechanisms have been put forward for immunity to malaria, their importance remains to be clarified. One of the important findings is that nonactivated monocytes and macrophages showed marked antiplasmodial activity in vitro. Recently we postulated that parasites may induce host factors that may depress the natural antiplasmodial activity of monocytes. In this investigation we identify IL-4 as a lymphokine that could function in this capacity. Human monocytes and macrophages in the absence of antiplasmodial antibody showed substantial killing of the asexual erythrocytic forms of Plasmodium falciparum as determined by a radiometric assay. Suppression of this killing was seen if the mononuclear phagocytes were pretreated with human rIL-4 at concentrations of 10 to 250 U with optimum activity between 100 and 250 U/2 x 10(5) cells. Cells from some individuals were rendered completely inactive by the IL-4 treatment. In contrast, IL-4 did not affect the neutrophil-mediated anti-P. falciparum activity. Our work identifies a potentially important parasite immune evasion mechanism involving IL-4 suppression of macrophage antiparasite activity.
Predominance of VH-D-JH junctions occurring at sites of short sequence homology results in limited junctional diversity in neonatal antibodies.
Authors: Feeney A J 
Published: December 2022

Abstract
Sequence diversity at the junctions of Ig genes differs between newborn and adult mice in two respects: 1) fetal/newborn Ig lack N regions; and 2) these N- junctional sequences very often contain 1 to 6 nucleotides that could have been encoded by either of the two joined gene segments. We address the hypothesis that such short homologies preferentially direct recombination to that site, and we analyze the effect of such homology-directed recombination upon the neonatal Ig repertoire. We examined 546 CDR3 sequences that were generated from polymerase chain reaction-amplified DNA from fetal and newborn liver using primers from three different VH families: S107, 7183, and J558. All junctional sequences using 14 frequently occurring IgH V-D and D-J gene combinations were analyzed. In 12 of the 14 combinations analyzed, there were 1 to 3 short sequence homologies, and the junctional sequences that would be created by those homologies were observed with high frequency. The D-J junctions often had two to three predominant junctional sequences, whereas the V-D junctions had one dominant junctional sequence. The only exceptions were the VHJ558-D junctions, where homology-directed recombination using the sequence homology between VHJ558 genes and most D genes would result in an out-of-frame join, and most of our sequences were productive. This latter result further suggests that homology-directed recombination may play a role in the nonrandom VH gene usage observed in fetal and newborn mice. Thus, most neonatal IgH junctions show limited diversity, not only due to the lack of N regions, but also because of nonrandom junctional sequences. Inasmuch as the few adult N- junctions also show a high frequency of homology-directed junctional sequences, V-D-J recombination throughout life may involve pairing via short homologies, with addition of N regions obscuring its role in the formation of adult IgH junctions.
CD28-induced T cell activation. Evidence for a protein-tyrosine kinase signal transduction pathway.
Authors: Lu Y , Granelli-Piperno A , Bjorndahl J M , Phillips C A , Trevillyan J M 
Published: December 2022

Abstract
CD28 is a 44-kDa homodimeric receptor expressed on the majority of T cells. Engagement of the CD28 receptor by soluble anti-CD28 mAb in conjunction with PMA causes the induction of lymphokine/cytokine production and proliferation in resting T cells via signal transduction pathways independent of the TCR. The precise nature of the biochemical events that occur after perturbation of the CD28 receptor remain unclear. We report evidence for the coupling of CD28 to a protein-tyrosine kinase pathway. Multivalent cross-linking of the CD28 receptor or stimulation by soluble CD28 mAb plus PMA, but not PMA or soluble CD28 mAb alone, reproducibly caused the rapid (within 2 min) tyrosine phosphorylation of a 100-kDa cellular substrate. In some experiments, additional cellular substrates of 110, 85, 74, 68, 56, 43, and 29 kDa were also observed. The tyrosine phosphorylation of these substrates was completely inhibited by 12 h pretreatment of T cells with herbimycin A, a selective inhibitor of src-family protein-tyrosine kinases. Pretreatment of T cells with herbimycin was without effect on CD28 surface expression but did inhibit CD28 mAb plus PMA-induced IL-2 mRNA levels, IL-2R(CD25) up-regulation, and cell proliferation. The inhibition of IL-2 mRNA levels was likely at the level of transcription, because herbimycin inhibited NF-AT, AP-1, and CD28RC but not NF-kappa B or OCT-1 binding activities to their respective IL-2 enhancer region sequences. Herbimycin did not inhibit PMA-dependent events including CD69 surface expression, NF-kappa B nuclear binding activity or the level of CD25 induced by PMA alone, supporting the notion that herbimycin is acting to inhibit a CD28 initiated or regulated protein-tyrosine kinase pathway(s).