bluuebunny/crossref_metadata_2025_split huggingface dataset:
IgG3 production in MRL/lpr mice is responsible for development of lupus nephritis.
Authors: Takahashi S , Nose M , Sasaki J , Yamamoto T , Kyogoku M 
Published: December 2022

Abstract
MRL/Mp-lpr/lpr (MRL/lpr) mice spontaneously develop lethal glomerulonephritis (GN) similar to human lupus nephritis, associated with the expression of lymphoproliferation gene lpr. To examine whether a particular IgG subclass is responsible for development of GN in these mice, first quantitative analysis of IgG subclasses in serum and in kidney eluates was performed. Although IgG2a was the dominant subclass in serum throughout the lifespan of mice, the IgG3 level in kidney eluates was three times higher than that of IgG2a at the 16 wk of age, which is the time of onset of development of severe GN. In sera of the 12-wk-old mice, half of the IgG3 was in immune complex form, whereas IgG2a in this form was only 17% of the total amount. Second, cyclosporin A, which ameliorates GN in MRL/lpr mice despite autoantibody production, was found to reduce serum IgG3 and mRNA levels, associated with the revision of cationic shift of the serum IgG3 spectrotype seen in isoelectric focusing. Third, among the hybrid mice with non-autoimmune-prone C3H/HeJ-lpr/lpr (C3H/lpr) mice, MRL/lpr x (MRL/lpr x C3H/lpr) F1, in which the genetic background for GN is likely segregated, the mRNA level for IgG3 correlated well with the degree of glomerular lesion. These findings indicate that production of IgG3 in MRL/lpr mice is one of the major factors responsible for development of GN in these mice, and that this is due to the genetic background of the MRL strain.
Regulation of alloreactivity in vivo by IL-4 and the soluble IL-4 receptor.
Authors: Fanslow W C , Clifford K N , Park L S , Rubin A S , Voice R F , Beckmann M P , Widmer M B 
Published: December 2022

Abstract
Although numerous in vitro studies have demonstrated that cytokines are involved in the generation of alloreactive effector cells, the role of these regulatory substances in vivo is less well defined. We have recently cloned and expressed cDNAs encoding both membrane bound and soluble forms of the murine IL-4R. The effects of murine rIL-4 and a recombinant, soluble, extracellular portion of the murine IL-4R soluble(s) IL-4R on the generation of alloresponsiveness in vivo were evaluated by measuring the lymphoproliferative response to a localized injection of allogeneic cells and the survival of cardiac allografts. Administration of IL-4 to BALB/c mice resulted in a slight augmentation of the anti-C57BL/6 lymphoproliferative response compared to that occurring in control, mouse serum albumin-(MSA) treated mice. In contrast, the sIL-4R suppressed this response to allogeneic cells in a dose-dependent manner, with a dose of 50 micrograms/kg/day causing nearly complete inhibition of the response as compared to the response observed in controls. The inhibitory effect of sIL-4R was reversed by simultaneous administration of IL-4. A neutralizing antibody against IL-4 (11B11) and another against the IL-4R (M1) were also effective inhibitors of the response when given at 100- to 1000-fold higher concentrations than the amount of sIL-4R required to inhibit the response. In cardiac allograft experiments, BALB/c mice were engrafted with newborn C57BL/6 hearts in the ear pinnae and treated with sIL-4R (50 micrograms/kg) or MSA. Such allografts survived an average of 4 days longer in sIL-4R-treated mice than in MSA-treated controls. In conclusion, neutralization of IL-4 inhibits alloresponsiveness in vivo. These results confirm a regulatory role for this pleiotropic cytokine in allograft rejection and suggest a therapeutic value for IL-4 antagonists alone or in combination with other immunosuppressive regimens.
HLA-binding regions of HIV-1 proteins. I. Detection of seven HLA binding regions in the HIV-1 Nef protein.
Authors: Choppin J , Martinon F , Connan F , Gomard E , Levy J P 
Published: December 2022

Abstract
The physical association of HLA class I or H-2 molecules with 36 HIV-1 Nef synthetic peptides was studied using a direct peptide binding assay (PBA) in solid phase. To assess the functional significance of the PBA results, the Nef peptides were also tested for their ability to inhibit the lytic activity of human or murine CTL. The PBA results showed that seven partly overlapping regions of the Nef protein contained MHC binding peptides (4-18, 46-67, 73-94, 100-128, 126-155, 182-198, and 192-206). Five of these seven regions included all the already described epitopes recognized by CD8+ human CTL. The two other regions, 4-18 and 46-67, are not yet described as antigenic for human CD8+ cells but they are located in the N-terminal part of Nef that was previously described as being stimulator for rat or chimpanzee CD4+ cells. Altogether, it can be concluded that 1) In virtually 100% of the cases, the PBA is capable to detect known antigenic peptides recognized by CTL. 2) The PBA and the functional inhibition assay provide similar results, supporting the functional significance of PBA results. 3) The PBA is easy to handle on a large scale, using multiple peptide and several MHC molecules, so that it can be used as a routine method for prevision of possibly epitopic sequences. 4) Systematic studies of peptides issued from the whole sequence of a given protein allow to map polyepitopic areas that are probably the most interesting parts of proteins for a vaccine purpose.
Site-directed mutagenesis of the region around Cys-241 of complement component C2. Evidence for a C4b binding site.
Authors: Horiuchi T , Macon K J , Engler J A , Volanakis J E 
Published: December 2022

Abstract
We probed the functional significance of the region around Cys-241 in human C2 by testing the hemolytic activity of a series of mutant rC2. Mutant C2 cDNA were constructed by oligonucleotide-directed site-specific mutagenesis and expressed transiently in COS cells. Wild-type rC2 had threefold higher specific hemolytic activity than native serum C2. Substitution of Gly, Ala, or Ser for Cys-241 resulted in a slightly, but significantly, increased activity. In addition, I2 had no effect on the activity of these mutant C2. Substitution of Lys for Gln-243 increased the hemolytic activity by more than two-fold. Increased activity in all cases was due to slower decay rates of the C3 convertase. Finally, substitution of Leu or Ala for Asp-240 or Ser-244, respectively, resulted in more than 100-fold decrease of hemolytic activity. The results suggest that residues 240 to 244 of human C2 represent an important structural determinant of the C4b binding site of C2a. They also confirm that Cys-241 is the residue responsible for the increased activity of C2 reacted with I2.
Invariant chain influences post-translational processing of HLA-DR molecules.
Authors: Schaiff W T , Hruska K A , Bono C , Shuman S , Schwartz B D 
Published: December 2022

Abstract
HLA class II MHC molecule alpha- and beta-chains are normally synthesized in the presence of a third molecule, the invariant chain (Ii). Although Ii is not required for surface expression of HLA class II molecules, the influence of Ii on post-translational processing and maturation HLA class II molecules has not been thoroughly studied. In the present study, BALB/c 3T3 cells were transfected with HLA-DR alpha- and beta-chains with or without co-transfection with human Ii. Although Ii had no effect on the surface expression of DR, Ii did have a profound effect on the post-translational processing of both the alpha- and beta-chains. In the absence of Ii, the major species of alpha- and beta-chains were of lower m.w. than when expressed in the presence of Ii. The differences in m.w. were shown to be caused by differences in glycosylation with the majority of alpha- and beta-chains remaining unprocessed and endo H sensitive in the absence of Ii. The small proportion of alpha-chains that were processed in the absence of Ii showed an altered m.w. and altered sensitivity to treatment with endo H relative to alpha-chains processed in the presence of Ii. Pulse/chase studies demonstrated that although the majority of the alpha- and beta-chains remained unprocessed in the absence of Ii, the small amount that was processed was done so at a rate similar to that observed for alpha- and beta-chains processed in the presence of Ii. These studies demonstrate that Ii influences the post-translational processing of human class II molecules by affecting the proportion of alpha- and beta-chains that are processed and by determining the degree of processing of oligosaccharides on mature alpha-chains.
Arachidonic acid is essential for IgG Fc receptor-mediated phagocytosis by human monocytes.
Authors: Lennartz M R , Brown E J 
Published: December 2022

Abstract
Phagocytosis is a specialized function of neutrophils and macrophages that requires coordination of multiple biochemical and biophysical events. Considerable progress has been made in identifying the membrane receptors involved in phagocytosis, but the intracellular signaling pathways that are necessary for particle ingestion are poorly understood. In an effort to address this complex question, we investigated the role of arachidonic acid (AA) in the uptake of yeast and IgG-coated E (EIgG) or C-coated E. Human monocytes, labeled with 3H AA, released this label during phagocytosis of yeast and EIgG, but not in response to EC3b. The PL inhibitors bromophenacyl bromide and manoalide abolished the release of 3H and inhibited phagocytosis of EIgG in parallel. Both drugs caused a similar inhibition of yeast-mediated 3H release but had little effect on yeast ingestion. Similar results were obtained with the inhibitor quinacrine (mepacrine). Exogenously added AA and dihomo-gamma-linolenic acid restored bromophenacyl bromide-inhibited EIgG ingestion; arachidonate analogs eicosatrienoic acid and eicosapentanoic acid did not. Inhibition of the cyclooxygenase and lipoxygenase pathways for AA metabolism by indomethacin or BW755C did not affect EIgG phagocytosis, demonstrating that these major AA metabolic pathways are not involved in phagocytic signaling. These experiments suggest that release of AA is essential for EIgG ingestion and that phagocytosis in monocytes proceeds by at least two mechanisms, one dependent on AA (EIgG) and one independent of it (yeast).
Genomic organization and subchromosomal in situ localization of the murine granzyme F, a serine protease expressed in CD8+ T cells.
Authors: Jenne D E , Zimmer M , Garcia-Sanz J A , Tschopp J , Lichter P 
Published: December 2022

Abstract
Granzyme F belongs to a closely related family of seven murine serine proteases stored in cytoplasmic granules of lymphoid cell populations. In contrast to the murine granzymes A to E and G, granzyme F is exclusively expressed in the CD4-CD8+ subset of peripheral T cells. To characterize the genomic sequences responsible for its highly restricted expression, we isolated a cosmid clone and sequenced a 7.5-kb genomic fragment that contains the promoter region and all five exons of the murine granzyme F gene. A TATA box sequence is located at position -25 relative to the transcription initiation site, which was determined by RNase protection. The genomic organization of granzyme F is similar to that of granzyme B and granzyme C, leukocyte elastase, cathepsin G, rat mast cell protease II, and complement factor D (adipsin). By the use of two fluorochromes for simultaneous high resolution in situ hybridization, the granzyme F gene was localized in close proximity distally from the TCR alpha-chain locus on mouse chromosome 14.
Nonrandom use of J alpha gene segments. Influence of V alpha and J alpha gene location.
Authors: Roth M E , Holman P O , Kranz D M 
Published: December 2022

Abstract
TCR genes (alpha, beta, gamma, and delta) undergo rearrangement during development in the thymus. The repertoire of alpha beta and gamma delta cells is shaped first by genetic processes that control rearrangement and expression and then by intercellular processes that "select" cells expressing only particular receptors. In this report, alpha chain transcripts from different stages of ontogeny were examined to determine the influence of V and J gene location on the thymic repertoire. J alpha gene segments were not used equally by V alpha genes. The frequency of J alpha use, and thus the alpha chain repertoire, was influenced by at least three factors: the location of the V gene, the location of the J gene, and the age of the animal. V genes that are proximal to the J alpha region preferentially use the most 5' J alpha gene segments. In contrast, a V alpha gene that is distal to the J alpha region was rarely joined to these same 5' J alpha gene segments in thymocytes from adult animals. We suggest that the data are most easily explained by the frequent occurrence of secondary rearrangements in which a V alpha J alpha rearranged gene would be replaced by the joining of a flanking V alpha gene to a flanking J alpha gene segment. Finally, the evidence suggests that there may be differences in the extent of secondary rearrangements between fetal and adult animals.
Effect of nephritogenic antibody on complement regulation in cultured rat glomerular epithelial cells.
Authors: Quigg R J , Cybulsky A V , Salant D J 
Published: December 2022

Abstract
In passive Heymann nephritis, a rat model of membranous nephropathy, antibody (anti-Fx1A) activates C on the surface of the glomerular epithelial cell (GEC), leading to GEC injury and proteinuria. In this study, we examined C activation by anti-Fx1A in cultured rat GEC. In addition to anti-Fx1A IgG, anti-Fx1A F(ab')2 and Fab' led to GEC injury in the presence of rat or human sera as sources of C. Cytotoxicity was Mg2+ and factor B dependent, but Ca2+ independent, indicating that anti-Fx1A activated the C alternative pathway (AP). Furthermore, in the presence of Mg2+ and factor B, anti-Fx1A enhanced 125I-C3b deposition on GEC in the absence of classical pathway activation. AP C3 and C5 convertases formed on GEC (GEC-C3bBbP) were inactivated over time, probably due to binding of GEC C regulatory proteins. This inactivation was prevented when GEC-C3bBbP were incubated with anti-Fx1A IgG. An antibody raised against cultured GEC that binds to GEC in vitro and in vivo had no effect on C3 and C5 convertases, suggesting that stabilization of C3bBbP is unique to anti-Fx1A. Anti-Fx1A Fab' also stabilized GEC-C3bBbP, indicating that cross-linking of membrane Ag was not required. C3bBbP on E were not affected by anti-Fx1A, excluding direct stabilization of convertases by anti-Fx1A. Therefore, anti-Fx1A inhibits C regulation on GEC, which can account for its ability to activate the AP. This represents a potentially powerful mechanism of producing disease in vivo.
Regulation of human lymphocyte proliferation by a heterodimeric cytokine, IL-12 (cytotoxic lymphocyte maturation factor).
Authors: Gately M K , Desai B B , Wolitzky A G , Quinn P M , Dwyer C M , Podlaski F J , Familletti P C , Sinigaglia F , Chizonnite R , Gubler U 
Published: December 2022

Abstract
IL-12 is a heterodimeric cytokine that was identified on the basis of its ability to synergize with IL-2 in the induction of cytotoxic effector cells and was originally called cytotoxic lymphocyte maturation factor (CLMF). IL-12 was also found to stimulate the proliferation of PHA-activated lymphoblasts which were greater than 90% CD3+ T cells. In this report we further characterize the effects of IL-12 on lymphocyte proliferation. Studies with purified subpopulations of PHA-activated lymphoblasts and with cloned lines of human T cells indicated that IL-12 caused the proliferation of activated T cells of both the CD4+ and CD8+ subsets. This effect of IL-12 was independent of IL-2 because it was not blocked by antibodies to either IL-2 or IL-2R. The maximum proliferation induced by IL-12 was 31 to 72% of the maximum caused by IL-2; however, IL-12 was active at a lower effective concentration (EC50 = 8.5 +/- 1.3 pM) than IL-2 (EC50 = 52 +/- 8 pM). Combination of suboptimal amounts of IL-12 and IL-2 resulted in additive proliferation, up to the maximum induced by IL-2 alone. IL-12 also caused the proliferation of lymphocytes activated by culture with IL-2 for 6 to 12 days. CD56+ NK cells were among the IL-12-responsive cells in the IL-2-activated lymphocyte population. Unlike IL-2 or IL-7, IL-12 caused little or no proliferation of resting peripheral blood mononuclear cells (PBMC). In this regard, IL-12 was similar to IL-4. However, IL-12 could enhance the proliferation of resting PBMC caused by suboptimal amounts of IL-2, whereas IL-4 inhibited IL-2-induced PBMC proliferation. Thus, IL-12 is a growth factor for activated human T cells and NK cells; however, its spectrum of lymphocyte growth-promoting properties is distinct from that of IL-2, IL-4, or IL-7.
Differentiation-inducing cytokine P48 exists in a membrane-associated form.
Authors: Kostyal D A , Beezhold D H , Hall R E 
Published: December 2022

Abstract
P48 is a recently described 48-kDa differentiation-inducing cytokine isolated from the culture medium of the human leukemia line Reh. P48 induces differentiation and cytolytic activity in the promyelocytic cell line HL-60, and stimulates the release of TNF-alpha and IL-1 from peripheral blood monocytes. In further studies designed to examine the biosynthesis and function of P48, surface immunofluorescence flow cytometry analysis as well as 125I surface labeling and immunoprecipitation, revealed the presence of P48 on the surface of Reh cells. Triton X-114-treated Reh cells were partitioned into detergent and aqueous phases and separated by SDS-PAGE. Western blot analysis revealed that P48 partitioned exclusively into the detergent phase, suggesting an integral membrane association. Reh cells fixed with paraformaldehyde, but not K562 or P815, were able to stimulate the release of TNF-alpha from peripheral blood monocytes in a manner similar to that of secreted P48. Isolated plasma membranes from Reh cells could also stimulate TNF-alpha release. This TNF-alpha-releasing activity could be removed from detergent solubilized Reh membranes by immunoaffinity chromatography on an anti-P48 column. This study suggests that, in addition to being secreted into the culture medium, P48 is expressed on the surface of Reh cells in a biologically active form. The membrane form of P48 may be 1) a final maturation step before secretion or 2) a cell membrane-associated form that may be analogous to the membrane forms of TNF-alpha and IL-1.
Detection of in ovo derived idiotypic antibodies. I. A model for maternal-neonatal idiotype network studies.
Authors: Ainsworth A J , Brown J E 
Published: December 2022

Abstract
Idiotypic vaccines appear to have many advantages over conventional vaccines. Maternal Id or anti-Id that are passively transferred to the fetus or neonate could provide another avenue for vaccination. Based on this premise we have investigated the transmission of idiotypic antibodies from dam to embryo by inoculating laying hens and analyzing their egg yolks for the presence of Id, anti-Id, and anti-anti-Id. The Ag chosen for these studies was BSA. After isolation and concentration BSA Id titers were approximately 256,000. The presence of anti-Id antibody in yolk samples is characterized by the ability of anti-Id to inhibit BSA binding to Id. The anti-Id extracted from yolks inhibited BSA binding to Id by 7 to 53%. Not all of the anti-Id present in samples was binding to a paratope-associated Id because 11 to 16% of the fluoresceinated anti-Id bound to Id-coated beads in the presence of excess BSA. Because a portion of the anti-Id antibodies were internal images of the BSA Id, they should be able to mimic Ag. This idea was confirmed when anti-Id inoculated in hens caused the synthesis of antibodies that would bind BSA and could be detected in an ELISA. Binding of anti-anti-Id to BSA-coated wells could be inhibited by preincubation of anti-anti-Id with BSA in solution. The chicken model provides a novel system to investigate maternal-fetal and maternal-neonatal interactions in the idiotypic network and the cellular mechanisms involved in the ontogeny of the Id network in neonates.
Microfilament assembly is required for antigen-receptor-mediated activation of human B lymphocytes.
Authors: Melamed I , Downey G P , Aktories K , Roifman C M 
Published: December 2022

Abstract
The mechanisms responsible for initiating the conversion of globular to filamentous actin (assembly) after stimulation of B lymphocytes and the role of these cytoskeletal changes in cell activation are incompletely understood. We investigated the molecular basis of the signals leading to actin polymerization and concentrated on the involvement of guanosine triphosphate (GTP)-binding regulatory proteins, and protein kinase C (PKC). In addition, we related these early events to later events in B-cell activation, including cell proliferation. Cross-linking the Ag receptor with Staphylococcus aureus Cowan I (SAC) or anti-IgM antibodies, or stimulation of PKC with phorbol ester induced a time- and concentration-dependent increase in the filamentous actin content of B cells. Inhibition or depletion of PKC resulted in decreased actin assembly induced by anti-IgM, SAC, and PMA, suggesting that the signal for polymerization is generated distally to PKC activation. Pertussis toxin pretreatment inhibited the responses to anti-IgM and SAC but not PMA, and direct stimulation of permeabilized cells with GTP gamma S induced microfilament assembly, indicating the involvement of a GTP-binding protein for receptor-mediated events. Disruption of actin polymerization with botulinum C2 toxin or cytochalasin D inhibited the assembly of actin and [3H]TdR incorporation induced by all stimuli. We conclude that human B cell activation by receptor-mediated stimuli results in actin polymerization by signaling pathways coupled to GTP-binding proteins. These changes in the cytoskeleton may be involved in the transduction of messages leading to responses such as proliferation in B lymphocytes.
Human articular cartilage and chondrocytes produce hemopoietic colony-stimulating factors in culture in response to IL-1.
Authors: Campbell I K , Novak U , Cebon J , Layton J E , Hamilton J A 
Published: December 2022

Abstract
The hemopoietic CSF, granulocyte-macrophage CSF (GM-CSF) and granulocyte CSF (G-CSF), are cytokines that mediate the clonal proliferation and differentiation of progenitor cells into mature macrophages and/or granulocytes. We have employed an all-human cell culture system, specific ELISA for GM-CSF and G-CSF, and Northern analysis to investigate whether chondrocytes are a potential source of CSF in rheumatoid disease. We report that human rIL-1 stimulated in a dose-dependent manner the production of GM-CSF and G-CSF by human articular cartilage and chondrocyte monolayers in organ and cell culture, respectively. Increased levels of the CSF Ag were detected after 2 to 8 h stimulation with IL-1, and the optimum dose of IL-1 was 10 to 100 U/ml (0.06 to 0.6 nM IL-1 alpha; 0.02 to 0.2 nM IL-1 beta); neither CSF was detectable in nonstimulated cultures nor in IL-1-stimulated cultures treated with actinomycin D or cycloheximide, indicating the requirement for de novo RNA and protein synthesis. The IL-1-mediated increase in GM-CSF could also be inhibited by the corticosteroid, dexamethasone, but not by the cyclo-oxygenase inhibitor, indomethacin. Although having little effect when tested alone, TNF-alpha and lymphotoxin (TNF-beta) could synergize with IL-1 for the production of GM-CSF. Basic fibroblast growth factor, platelet-derived growth factor, and IFN-alpha and IFN-gamma each had no effect on GM-CSF levels. Results obtained by Northern analysis of chondrocyte total RNA reflected those found for the CSF Ag, namely that CSF mRNA levels were elevated in response to IL-1, but not TNF, and that there was synergy between these two cytokines. We propose that chondrocyte CSF production in response to IL-1, and the concurrent destruction of cartilage by IL-1, could provide a mechanism for the chronic nature of rheumatoid disease.