bluuebunny/crossref_metadata_2025_split huggingface dataset:
Human cord blood antibody repertoire. Mixed population of VH gene segments and CDR3 distribution in the expressed C alpha and C gamma repertoires.
Authors: Mortari F , Wang J Y , Schroeder H W 
Published: December 2022

Abstract
Developmental regulation of the diversity of the antibody repertoire is associated with the controlled stepwise acquisition of Ag responsiveness during ontogeny. The development of IgG and IgA serum levels in humans lags far behind the maturation of the rest of the immune response. We cloned cord blood mononuclear cell C gamma and C alpha transcripts and compared them with a large database of &gt; 250 published and unpublished sequences, including C mu transcripts from this same cord blood cDNA library, to determine whether restrictions in the expressed antibody repertoire contributed to the limitations of the neonatal IgG and IgA response. We found a diverse antibody repertoire containing a high frequency of the same VH gene segments first identified in fetal liver, as well as VH elements homologous to those in the cord blood C mu transcripts. Although VH, DH, and JH utilization differed, the distribution of CDR3 lengths in the C gamma transcripts was similar to that found in fetal liver C mu transcripts, whereas the distribution of CDR3 lengths in the C alpha transcripts was similar to that found in cord blood C mu. This comprehensive analysis of the C mu, C gamma, and C alpha V domain repertoires provides new insights into our understanding of the timing of sequential B cell waves that seed peripheral lymphoid compartments during development.
HLA-unrestricted killing of HSV-1-infected mononuclear cells. Involvement of either gamma/delta+ or alpha/beta+ human cytotoxic T lymphocytes.
Authors: Maccario R , Revello M G , Comoli P , Montagna D , Locatelli F , Gerna G 
Published: December 2022

Abstract
The characterization of HSV-specific human CTL, obtained in short term cultures by stimulating PBMC of healthy HSV-immune donors with autologous, PHA-activated, HSV-1-infected mononuclear cells, is described. CTL induced by using this technique are able to mediate a strong lytic activity against both HSV-1- and HSV-2-infected targets, whereas they do not kill autologous EBV-lymphoblastoid cell lines unless they are superinfected with HSV-1. TCR-gamma/delta+ cells are mainly responsible for HSV-specific cytotoxic activity in some donors, whereas TCR-alpha/beta+ CTL are primarily involved in other subjects. The large majority of HSV-specific CTL bearing either TCR-gamma/delta or TCR-alpha/beta also express CD8 and/or CD56 molecules. Virus-specific CTL, here described, require the expression of HLA class I Ag on the surface of target cells to mediate lytic activity. Nevertheless, the response is apparently HLA-unrestricted in that HSV-1-induced CTL are also able to lyse target cells mismatched for A, B, C, DR, and DQ loci. Our data suggest that both TCR-gamma/delta+ and TCR-alpha/beta+ CTL may play a role in the immune response to HSV in humans.
Effector functions of circumsporozoite peptide-primed CD4+ T cell clones against Plasmodium yoelii liver stages.
Authors: Rénia L , Grillot D , Marussig M , Corradin G , Miltgen F , Lambert P H , Mazier D , Del Giudice G 
Published: December 2022

Abstract
Previously, CD4+ T cell lines and clones were isolated after immunization of BALB/c and C57BL/6 mice with the Py1 peptide, a 21-mer synthetic peptide corresponding to a N-terminal segment of the circumsporozoite protein of Plasmodium yoelii. The clones were separated into the Th1 and Th2 subsets on the basis of lymphokine production. It was observed that immunization with the Py1 peptide induced preferentially Th1 cells in BALB/c and Th2 cells in C57BL/6 mice. These clones were then tested for their cytolytic ability in vitro. Some of the clones from BALB/c and C57BL/6 mice eliminated liver stage parasites from cultured hepatocytes in a MHC restricted manner. Nevertheless, none of these clones was able to lyse Py1 peptide-pulsed target cells. It was also found that two clones could protect BALB/c mice against a sporozoite challenge. These results provide evidence that CD4+ T cells, induced after priming with a defined peptide, could participate in the effector mechanisms against malaria liver stages.
Induction of leukemia inhibitory factor in human synovial fibroblasts by IL-1 and tumor necrosis factor-alpha.
Authors: Hamilton J A , Waring P M , Filonzi E L 
Published: December 2022

Abstract
The cytokines, IL-1 alpha and TNF-alpha, induced a dose-dependent production of leukemia inhibitory factor (LIF) in cultured human synovial fibroblast-like cells, as measured by a radioreceptor competition assay. Significant levels of LIF were first detected in cell supernatants between 2 and 4 h after cytokine addition. Increases were also observed in LIF mRNA steady-state expression. Evidence is presented for down-regulation of the IL-1-induced LIF activity by an endogenous cyclo-oxygenase product(s); the glucocorticoid, dexamethasone, lowered the IL-1-induced LIF activity and mRNA expression. A synergistic effect was noted between the actions of IL-1 alpha and TNF-alpha, and between IL-1 and transforming growth factor-beta. IFN-gamma could not induce LIF formation in the synovial cells but inhibited the stimulatory effect of IL-1. These results suggest that cytokine-stimulated synovial fibroblasts may be a major source of intraarticular LIF production in the joints of patients with inflammatory arthritis. Synoviocyte-derived LIF may activate monocyte/macrophages in the lesions and may contribute to the bone changes and certain systemic manifestations in patients with inflammatory joint disease.
Receptor-activated calcium influx in human monocytes exposed to monocyte chemotactic protein-1 and related cytokines.
Authors: Sozzani S , Molino M , Locati M , Luini W , Cerletti C , Vecchi A , Mantovani A 
Published: December 2022

Abstract
Stimulation of human monocytes with monocyte chemotactic protein-1 (MCP-1) resulted in an increase of [Ca2+]i. The [Ca2+]i rise was dependent on external Ca2+, could be reconstituted by the addition of external Ca2+ and was blocked by Ni2+. Agonist-stimulated Ca2+ influx was demonstrated directly by the use of Mn2+: in the presence of extracellular Mn2+, MCP-1 and FMLP stimulated a dose-dependent quench in fluorescence of Fura-2-loaded monocytes. This quench was the result of stimulation of Mn2+ influx and was blocked by Ni2+ and by the Ca2+ channel inhibitor SC38249. Pretreatment of monocytes with verapamil and nifedipine or high depolarizing [K+] had no effect. MCP-1 did not induce production of inositol triphosphate nor turnover of phosphatidylinositol 4,5-biphosphate. Collectively, these results show that MCP-1 does not induce discharge of intracellular stores. This chemokine stimulates divalent cation entry (Ca2+ or Mn2+) by a mechanism independent of changes in [Ca2+]i, unrelated to voltage-dependent Ca2+ channels and presumably involving receptor-activated channels. In addition to MCP-1, also two other members of the chemokine Cys-Cys family, RANTES and MIP-1 alpha, stimulated [Ca2+]i increase. Exposure of human monocytes to either RANTES or MIP-1 alpha, had no effect on a subsequent stimulation by MCP-1. On the contrary, MCP-1 cross-desensitized monocytes for a subsequent stimulation with RANTES and MIP-1 alpha. These results suggest a certain level of receptor sharing among members of the Cys-Cys chemokine family.
Overlap of the anti-Sm and anti-DNA responses of MRL/Mp-lpr/lpr mice.
Authors: Bloom D D , Davignon J L , Cohen P L , Eisenberg R A , Clarke S H 
Published: December 2022

Abstract
Autoantibodies specific for the Sm ribonucleoprotein are spontaneously produced in patients with SLE and in mice of the MRL mouse strains. We have previously reported the characterization of the clonality and V region gene use of 41 MRL/Mp-lpr/lpr (MRL/lpr)-derived B cell hybridomas selected for Sm binding. In this report, we show that many of the expressed V genes of these hybridomas are also expressed by anti-DNA hybridomas of MRL/lpr mice. Moreover, the anti-Sm hybridomas from nine clonal groups produce antibodies that bind ssDNA, and those of five clones produce antibodies that also bind dsDNA. Sm/DNA-specific hybridomas, but not Sm-only-specific hybridomas, have a higher than expected content of arginine residues in CDR3 of the H chain, similar to MRL/lpr hybridomas selected on the basis of DNA binding. One clone displays intraclonal differences in DNA binding, inasmuch as the most extensively mutated members produce antibodies that are able to bind dsDNA and have a higher affinity for ssDNA than the least mutated members of this clone. Thus, DNA appears to be a selecting Ag in this response. These data indicate an overlap in the anti-Sm and anti-DNA autoimmune responses in MRL mice that may have implications for the activation of anti-Sm B cells, and for defining the spectrum of Ag targeted in SLE.
B cell tolerance induction by cross-linking of membrane IgM, but not IgD, and synergy by cross-linking of both isotypes.
Authors: Gaur A , Yao X R , Scott D W 
Published: December 2022

Abstract
Previous studies in our laboratory demonstrated that overnight exposure of adult splenic B cells to anti-Ig resulted in an unresponsive state characterized by decreased antibody synthesis but normal mitogen-driven proliferation (i.e., energy). Because both anti-F(ab')2 and anti-mu were equally effective at inducing tolerance, it was important to determine whether cross-linking of IgD together with or separately from IgM influenced the induction of unresponsiveness. Although anti-mu induced significant unresponsiveness, treatment of adult splenic B cells with anti-delta alone generally failed to reduce the subsequent response to either LPS or fluoresceinated Brucella abortus. Interestingly, anti-delta synergized with suboptimal concentrations of anti-mu to induce tolerance. Synergy could be observed in this system when anti-delta was added either simultaneously with or before (but not after) anti-mu; moreover, anti-delta was effective in a pretreatment (wash-out) protocol. To investigate the role of protein tyrosine kinase (PTK) activity in tolerance induction, splenic B cells were treated with tyrphostin before treatment with either anti-mu or anti-delta. We found that pretreatment with tyrphostin for 2 h before the addition of anti-mu prevented the induction of unresponsiveness with this antibody, whereas this PTK inhibitor facilitated tolerance when used with anti-delta treatment only. We propose that cross-linking of surface IgM directly or indirectly invokes a tyrphostin-sensitive, PTK-dependent pathway leading to the early events in tolerance induction, which can be augmented under limiting conditions by anti-IgD. Because cross-linking of either receptor initiates several common pathways, simultaneous cross-linking can lead to synergy and a dominance of the IgM signal. In contrast, IgD alone may fail to elicit tolerance because this isotype may also be associated with different PTK that cause positive signaling.
Effect of prostaglandin E2 (PGE2) on IL-3/granulocyte-macrophage colony-stimulating factor production by T helper cells. Mode of stimulation and presence of costimulation can determine response to PGE2.
Authors: Li T K , Fox B S 
Published: December 2022

Abstract
PGE2 is an immunomodulator that selectively inhibits the production of lymphokines associated with Th1 cells (IL-2 and IFN-gamma) but not Th2 cells (IL-4 and IL-5). We examined the effect of PGE2 on the production of IL-3 and granulocyte-macrophage (GM)-CSF from murine Th1 and Th2 clones. When the T cells were stimulated with Ag and APC, PGE2 inhibited IL-3/GM-CSF production from 3 Th1 clones and 1 Th2 clone, but enhanced production from 3 Th2 clones. A more specific bioassay demonstrated that IL-3 production was differentially affected by PGE2 in the Th clones. These data suggested that the effect of PGE2 on IL-3 production is dependent, not on a property of the lymphokine, but on a property of the T cell. The responsiveness to PGE2 did not consistently differ between Th1 and Th2 cells, and the observed heterogeneity in the response of Th2 clones did not correlate with the ability to induce increases in intracellular [Ca2+]. However, we postulated that signaling differences between the clones might explain the varied responsiveness to PGE2. If so, then the mode of stimulation might be expected to activate different pathways and thus affect the PGE2-responsiveness. Stimulation with ionomycin induced variable levels of IL-3/GM-CSF from the T cell clones. APC-derived costimulation dramatically enhanced IL-3/GM-CSF; the cells which produced high levels in response to ionomycin alone were not detectably costimulating each other. Interestingly, PGE2 enhanced IL-3/GM-CSF (and IL-3 alone in at least some cases) from cells stimulated with ionomycin alone, demonstrating that the mode of stimulation affects the PGE2-responsiveness. Addition of APC not only enhanced lymphokine production, but also altered the PGE2-responsiveness of the Th1 cells. In these cells, PGE2 either inhibited IL-3 and GM-CSF production or had no effect, in no case was the lymphokine production enhanced by PGE2 as it had been with ionomycin alone. These data indicate that the presence of APC-derived costimulatory signals can alter the effect of PGE2 on Th cell lymphokine production.
Costimulatory signals are required for optimal proliferation of human natural killer cells.
Authors: Robertson M J , Manley T J , Donahue C , Levine H , Ritz J 
Published: December 2022

Abstract
CD56dim NK cells, which comprise approximately 90% of human peripheral blood NK cells, respond to IL-2 with cytokine production, up-regulation of functionally relevant surface molecules, and augmented cytolytic activity. Nevertheless, CD56dim NK cells proliferate poorly in response to IL-2 alone. We found that other NK cell mitogens, including IL-4, IL-7, and IL-12, also induced little proliferation of CD56dim NK cells. Indeed, IL-2 stimulated at least 10-fold more NK cell proliferation than did IL-4, IL-7, or IL-12. In contrast, leukocyte-conditioned medium (LCM) induced two- to threefold greater proliferation of CD56dim NK cells than did optimal concentrations of IL-2. Although the calcium ionophore ionomycin did not stimulate proliferation by itself, it markedly augmented LCM-induced proliferation of CD56dim NK cells. Proliferation in response to either LCM alone or LCM together with ionomycin was almost completely abrogated by anti-IL-2R antibodies. Thus, IL-2 appears to be necessary but not sufficient for optimal proliferation of CD56dim NK cells. LCM-induced proliferation of ionomycin-activated CD56dim NK cells was inhibited 24% by anti-IL-1 heteroantisera and 57% by anti-TNF antisera; a combination of both antisera inhibited proliferation by 73%. Furthermore, although rIL-1 and TNF did not induce proliferation by themselves, both cytokines could augment IL-2-induced proliferation of resting or ionomycin-activated NK cells. Hence IL-1 and TNF do not appear to be primary NK cell mitogens, but rather accessory factors that can enhance IL-2-dependent NK cell proliferation. Stimulation through CD2 or CD16 Ag did not enhance LCM-induced NK cell proliferation. However, stimulation with NK-sensitive K562 cells strongly augmented CD56dim NK cell proliferation to LCM or to IL-2, IL-1, and TNF in combination. NK-resistant Daudi cells did not promote the proliferation of highly purified NK cells. Thus, NK cell proliferation may be enhanced by triggering through putative receptors for natural killing, and ionomycin may mimic such triggering. Although IL-2 by itself can induce NK cell proliferation, most NK cells resemble T and B lymphocytes in that they require multiple signals for optimal proliferation.
DNA regions flanking the mouse Ig 3' alpha enhancer are differentially methylated and DNAase I hypersensitive during B cell differentiation.
Authors: Giannini S L , Singh M , Calvo C F , Ding G , Birshtein B K 
Published: December 2022

Abstract
Two B cell-specific enhancer elements are associated with the IgH gene cluster. One enhancer is located within the J-C mu intron (E mu), whereas a second enhancer (3' alpha E) is approximately 12.5 kb 3' of the C alpha membrane exon. In an attempt to understand the function of 3' alpha E, we have characterized its surrounding structural milieu during various stages of B cell differentiation through analysis of methylation patterns and the identification of DNAse I-hypersensitive sites. We observed a correlation between the chromatin structure of this region and the differentiation state of the cell. Compared to liver and brain, the region 3' of alpha was hypermethylated in pre-B and T cell lines and became progressively demethylated as B cell differentiation continued. A DNAse I-hypersensitive site was present in pre-B cell lines about 17 kb 3' of 3' alpha E. In fully differentiated myeloma cell lines, a second cluster of DNAse I-hypersensitive sites was present immediately 5' of 3' alpha E. Our data indicate that the 3' alpha enhancer is relatively sequestered during early stages of B cell differentiation and becomes increasingly accessible at later stages.
Verification of a model of a F(ab) complex with phenylarsonate by oligonucleotide-directed mutagenesis.
Authors: Sompuram S R , Sharon J 
Published: December 2022

Abstract
A model of the combining site of a mouse antibody specific for p-azophenylarsonate was tested by oligonucleotide-directed mutagenesis of the proposed hapten-contacting residues, Arg96 in the L chain, and Asn35, Trp47, Tyr50, Ser95, and Tyr100b in the H chain. The affinity and relative affinity for p-azophenylarsonate-N-acetyl-L-tyrosine of mutant antibodies expressed in transfectomas were determined by fluorescence quenching and by inhibition ELISA, respectively. The results show that alteration of the proposed contacting residues has drastic effects on hapten binding, and that the hydroxyl groups of Tyr50 and Tyr100b appear to orient the phenyl rings for optimal aromatic-aromatic interactions with the phenyl ring of the hapten. They further indicate a tight packing of the contacting residues around the hapten, which cannot accommodate changes in the positions of the functional groups of Asn35 and Ser95.
Characterization of an unusual cell type (CD4+ CD3-) expanded by helminth infection and related to the parasite stress response.
Authors: Estes D M , Turaga P S , Sievers K M , Teale J M 
Published: December 2022

Abstract
Mice infected with the parasite Mesocestoides corti develop hypergammaglobulinemia, hepatomegaly, and splenomegaly. The immune response to M. corti infection is directed, in part, at molecules secreted by the organism. Two of these molecules have been shown to be hsp70 and hsp60 homologues. In this study it was found that incubation of splenocytes from infected animals with M. corti-secreted molecules or the isolated M. corti hsp70 results in the expansion of an unusual cell type with the morphology of large granular lymphocytes. The cell lines express Thy-1, CD4 (low), and CD45RB but lack TCR alpha beta, TCR gamma delta, CD3, CD8, and slg. The lack of a TCR suggested NK cells, but no cytolytic activity could be detected. In addition, the cell lines constitutively produce IL-6 and can be induced to express IL-2, but not IL-4, IL-5, or IFN-gamma. Given the phenotype of these cells, it is possible that they represent T lineage precursors or some type of effector cells. Notably, CD3- CD4+ cells appear to be expanded in the spleens and livers of M. corti-infected animals, suggesting an important role in infection. Moreover, the selective growth of this cell type with M. corti hsp70 suggests that the outgrowth and in vivo expansion of these cells may be related to the stress response of the parasite.
Leishmania major interferes with antigen presentation by infected macrophages.
Authors: Fruth U , Solioz N , Louis J A 
Published: December 2022

Abstract
Impairment of the Ag-presenting capacity of macrophages harboring intracellular Leishmania might represent one of the several mechanisms by which these parasites can evade host-protective T cell responses. Thus, the present study was designed to investigate the ability of macrophages, parasitized with Leishmania major, to present Ag to relevant T cell hybridomas. Results show that bone marrow-derived macrophages from BALB/c mice, after infection with L. major, have a greatly reduced capacity to present OVA, beta-galactosidase, and L. major-derived Ag to specific T cell hybrids derived from mice immunized with those Ag. In contrast, after pulsing with relevant peptide, macrophages containing L. major have a normal Ag-presenting capacity. The inhibition of presentation of native Ag did not appear to result from decreased endocytosis or catabolism. Inasmuch as the inhibition of presentation could not be attributed to an impaired processing of the Ag or an unavailability of MHC class II molecules on the surface of infected cells, these results could indicate that the presence of L. major interferes with the intracellular loading of MHC class II molecules with antigenic peptides.
Vaccination with recombinant filarial paramyosin induces partial immunity to Brugia malayi infection in jirds.
Authors: Li B W , Chandrashekar R , Weil G J 
Published: December 2022

Abstract
Vaccination with irradiated infective larvae induces partial protective immunity to infection with the filarial nematode Brugia malayi in jirds. Prior studies have shown that such immunization stimulates a much stronger antibody response to recombinant and native filarial paramyosin than that seen after normal infection. To determine whether vaccination with recombinant paramyosin could induce protective immunity to larval challenge, jirds were immunized with either B. malayi paramyosin and maltose binding protein (BM5-MBP) (fusion protein of B. malayi paramyosin and maltose-binding protein), MBP alone, or recombinant Dirofilaria immitis paramyosin. Animals were challenged with 100 infective larvae s.c. 8 wk after the second immunization. Necropsies were performed 16 wk after challenge. Vaccination with BM5-MBP induced significant protective immunity; adult worm recoveries, worm lengths, and blood microfilaria counts were reduced in the BM5-MBP group relative to the MBP control group. The reductions in adult worm recoveries (43%) and female worm lengths (10%) were statistically significant (p &lt; 0.05). Interestingly, protective immunity was not induced by immunization with D. immitis paramyosin. Additional studies are needed to identify mechanisms involved in protective immunity induced by BM5-MBP and to understand the differential activity of the two closely related recombinant paramyosin proteins in this model.