bluuebunny/crossref_metadata_2025_split huggingface dataset:
Two neutralizing domains in the V3 region in the envelope glycoprotein gp125 of HIV type 2.
Authors: Björling E , Chiodi F , Utter G , Norrby E 
Published: December 2022

Abstract
The purposes of this study were to map the targets for neutralizing Abs in the HIV-2 glycoproteins with particular emphasis on the role of the V3 region. Sera obtained from guinea pig immunized with peptides representing five immunogenic regions of the envelope proteins were used in cross-neutralization experiments with nine HIV-2 isolates. Broad cross-neutralizing activity was elicited by immunization with two peptides representing the central and COOH-terminal portions of the HIV-2 V3 loop. Murine mAbs were established from animals immunized with two corresponding overlapping peptides. Six mAbs showed neutralizing activity against the homologous virus isolate SBL-6669. Peptide absorption experiments were performed to define the target regions for human neutralizing Abs in the HIV-2 envelope glycoproteins. A significant blocking of neutralizing activity of five HIV-2 Ab-positive sera was seen in the presence of two peptides corresponding to the V3 region. Two overlapping deletion sets of peptides, representing amino acids Ser311 and Arg337, were used to identify the role of individual HIV-2 V3 amino acids in the binding of polyclonal and mAbs. Two distinct antigenic sites were identified in this region, the first corresponding to a region including the conserved motif Phe-His-Ser (amino acid 315-317) and the second in proximity of the COOH-terminal cysteine Trp-Cys-Arg (amino acid 329-331). Potentially these two sites can interact to represent a single discontinuous antigenic site. Taken together, these results indicate that V3 is an important neutralizing domain of HIV-2.
Chronic treatment of C3H-lpr/lpr and C3H-gld/gld mice with anti-CD8 monoclonal antibody prevents the accumulation of double negative T cells but not autoantibody production.
Authors: Giese T , Davidson W F 
Published: December 2022

Abstract
Mice homozygous for lpr or gld develop autoimmunity and progressive lymphoproliferative disease characterized by the accumulation of an unusual population of functionally impaired B220+, TCR-alpha/beta +, CD4-, CD8- double negative (DN) T cells. Although these cells are thymus derived and appear to have undergone thymic negative selection, the identity of their immediate precursors and the mechanisms leading to their accumulation are poorly understood. Here we investigated the role of CD8+ T cells in the development of lymphoproliferative disease and autoantibody production. We showed that treatment of C3H-Ipr or C3H-gld mice with anti-CD8 mAb beginning at 3 wk of age and continuing to 15 wk of age caused a dramatic reduction in lymphadenopathy. the change in lymph node size resulted predominantly from a very significant decrease in both the proportions and the total numbers of B220+ DN T cells. The proportions of these cells were reduced up to 20-fold and the total numbers per LN up to 400-fold. Although chronic treatment with anti-CD8 mAb had the most profound effects on B220+ DN T cells, it also decreased the numbers of CD4+ T cells, CD4+B220+ T cells, and B cells in Ipr and gld LN up to fivefold. In contrast to its impact on lymphoproliferative disease, anti-CD8 mAb therapy had no significant effect on B cell hyperactivity. Comparisons of serum Ig and autoantibody levels in CD8+ T cell-depleted and control mAb-treated Ipr and gld mice revealed no changes in the elevated concentrations of serum IgM or total IgG and no significant reduction in the levels of circulating autoantibodies specific for thymocytes or dsDNA. The presence of active germinal centers and accumulations of plasma cells in the LN and spleen of anti-CD8 mAb-treated Ipr and gld mice provided further evidence for sustained B cell activation. These results suggest that in Ipr and gld mice, CD8+ T cells play a crucial role in the accumulation of B220+ DN T cells and also may contribute to the characteristic increase in the numbers of B cells and CD4+ T cells in these mice, but have no significant effect on B cell hyperactivity or autoantibody production.
Cytokine-enhanced NK cell-mediated cytotoxicity. Positive modulatory effects of IL-2 and IL-12 on stimulus-dependent granule exocytosis.
Authors: Bonnema J D , Rivlin K A , Ting A T , Schoon R A , Abraham R T , Leibson P J 
Published: December 2022

Abstract
NK cells are a subpopulation of lymphocytes that kill virally infected cells and tumor cells without previous sensitization. Although exposure to distinct cytokines, including IL-2 and IL-12, can enhance these cytotoxic responses, the mechanism of this lymphokine-augmented killing remains unclear. Inasmuch as the cytotoxic event is a multistep process, there are many potential targets for lymphokine regulation. We focused on whether selected lymphokines directly modulate the intracellular signaling pathways critical for NK cell secretory function. In our experimental model, homogeneous, cloned human CD16+/CD3- NK cells were pretreated with either IL-2 or IL-12 and then stimulated with direct pharmacologic activators of the secretory response (e.g., PMA and ionomycin for intact cells or GTP gamma S for streptolysin-O permeabilized cells). Previous exposure of the cells to IL-2 or IL-12 enhanced the stimulus-induced release of granule-derived proteins (hexosaminidase and serine proteases) in a cytokine concentration- and time-dependent fashion. Furthermore, the cytokines increased the efficacies without changing the potencies of the secretagogues used in these studies. These results suggest that IL-2 and IL-12 augment NK cell-mediated cytotoxicity by increasing the maximal level of granule exocytosis evoked by Ca2+ and/or G protein-dependent intracellular signaling pathways.
Effects of IL-12 on helper T cell-dependent immune responses in vivo.
Authors: McKnight A J , Zimmer G J , Fogelman I , Wolf S F , Abbas A K 
Published: December 2022

Abstract
The differentiation of naive T cells to the Th1 or Th2 subset of effector cells is regulated by the cytokines to which T cells are exposed at the time of antigenic stimulation. Mice immunized with a hapten-protein conjugate and treated systemically with IL-12 show a marked inhibition of IL-4-secreting cells and suppressed production of anti-hapten IgG1 Ab, as well as a marked enhancement of IFN-gamma-producing T cells. Thus, IL-12 is a potent inhibitor of Th2 differentiation and an inducer of Th1 development in vivo. The IFN-gamma-inducing effect of IL-12 is partially blocked by pretreatment of mice with anti-asialo GM1 (anti-NK cell) Ab, but anti-asialo GM1 does not abrogate any of the other systemic actions of IL-12. Furthermore, none of the effects of IL-12 is prevented by treating mice with neutralizing anti-IFN-gamma Abs. These results suggest that the effects of IL-12 may be mediated both via NK cell stimulation and by directly altering the differentiation patterns of T cells. Finally, a neutralizing anti-IL-12 Ab significantly inhibits Th1 responses to Ag, indicating that IL-12 may play an obligatory role in Ag-induced Th1 differentiation in vivo.
Properties of a novel gene isolated from a Hodgkin's disease cell line that is expressed early during lymphoid cell activation.
Authors: Bennett J S , Tredway T L , Dizikes G J , Nawrocki J F 
Published: December 2022

Abstract
We have isolated a novel 667-bp cDNA clone, designated epag, from a Hodgkin's-disease cell line-derived library that is expressed in association with T cell activation and which is not related to any known gene family. By using reverse transcription/PCR, we have demonstrated that epag mRNA is expressed as early as 1 h after stimulation of normal PBMCs with anti-CD3. The levels of mRNA peaked by 4 h, and no expression was detectable by 12 h postactivation or in resting cells incubated in culture without activation. Expression of epag was also detected in PMA- and PHA-stimulated, but not in nonstimulated Jurkat cells, and overall its expression in transformed cell lines of hemopoietic origin is highly restricted. Sequence analysis of multiple independent cDNA clones showed that epag expressed in the Hodgkin's-disease cell line L428 is identical to the gene expressed in normal activated PBMC. Epag expression was detected by reverse transcription/PCR in RNA preparations made from various normal nonlymphoid tissues. Computer analysis of the sequence identified an open reading frame encoding a putative protein of 13.2 kDa initiating at a CUG translational codon. In vitro translation and Western blot analysis with anti-peptide serum supported this analysis. We hypothesize that epag functions as an early signal that helps mediate the activation of T cells.
Expansion and contraction of rhesus macaque DRB regions by duplication and deletion.
Authors: Slierendregt B L , Otting N , van Besouw N , Jonker M , Bontrop R E 
Published: December 2022

Abstract
Previous sequence analysis of the rhesus macaque MHC (MhcMamu) class II DRB region has allowed the detection of at least 34 alleles belonging to different lineages. In this communication, 36 new Mamu-DRB alleles are reported. The gene content of the DRB region has been determined for several homozygous animals of consanguineous origin. As in other primates, the number of DRB genes present per haplotype is not constant, varying from two to six genes in rhesus macaques. Six major groups of DRB haplotypes have been defined in our rhesus macaque colony. Two haplotype groups were found to carry, as well as other Mamu-DRB genes, two genes that cluster into distinct HLA-DRB1 lineages. In one of these two groups, a haplotype harbors another two sets of DRB alleles that belong to the Mhc-DRB6 and -DRB*W6 lineages, respectively. Such a haplotype was probably generated by duplication, and our data suggest that after this particular expansion of the DR region, one of the duplicated Mamu-DRB6 alleles was the target of an Alu insertion. Although certain transspecies allelic lineages are evolutionarily stable, and have been conserved for at least 36 million years, the rhesus macaque class II haplotypes differ significantly from those found in humans, chimpanzees, and gorillas. Mhc-DRB regions are therefore comparatively unstable over longer evolutionary time spans, with regard to both the number of genes and the gene content, and must have been subjected to expansion and contraction.
A 100-kDa protein in the C4-activating component of Ra-reactive factor is a new serine protease having module organization similar to C1r and C1s.
Authors: Takayama Y , Takada F , Takahashi A , Kawakami M 
Published: December 2022

Abstract
Ra-reactive factor (RaRF), a C-dependent bactericidal factor in mice, is composed of one polysaccharide-binding component and one C4/C2-activating component. The former is an oligomer of 28-kDa protein corresponding to the mannose-binding protein of mice. The 100-kDa protein, P100, has been shown to be present in the C4/C2-activating component. This protein generates 29- and 70-kDa polypeptide chains when reduced. In this study, we determined the nucleotide sequence of cDNA coding for P100. cDNAs were prepared by reverse transcription PCR and cassette-ligation-mediated PCR on mRNA from BALB/c mouse liver, using primers synthesized by reference to the sequence determined in a previous study. The results of cDNA sequencing indicate that the precursor protein of P100 containing a 24-residue signal peptide consists of 704 amino acid residues. Taking the results of the previous electrophoretic study into consideration, it is thought that the cleavage of mature P100 protein generates a 29-kDa chain of 251 residues and a 70-kDa chain of 429 residues. Although homology in the amino acid sequence of P100 with that of human C1r and C1s subcomponents of C was less than 40%, a striking similarity in domain organization was found among these proteins, indicating that P100 is a new C4-activating serine protease structurally similar to C1r and C1s. Northern hybridization showed that the liver was the primary site of the expression of the P100 gene.
Sensitivity of human leukemia cells in exponential or stationary growth phase to anti-CD5 immunotoxins. Role of intracellular processing events.
Authors: Chignola R , Anselmi C , Franceschi A , Pasti M , Candiani C , Tridente G , Colombatti M 
Published: December 2022

Abstract
We have assayed the sensitivity of Jurkat cells in different growth phases to an anti-CD5-ricin A chain (ST.1-RTA) immunotoxins (IT). Jurkat cells proliferated exponentially until a stationary growth phase was reached. Proliferating and stationary cells displayed marked differences in sensitivity to ST.1-RTA treatment; the time required to kill one log of target cells (T10) was 70 h in proliferating and 12 h in stationary cells, respectively. Differences in sensitivity to IT treatment were greatly diminished by the addition of the IT enhancer monensin (T10 = 4.9 and 3.5 h in proliferating and stationary cells, respectively). Binding and internalization studies carried out with fluoresceinated ST.1 mAb revealed that the higher sensitivity of stationary cells to ST.1-RTA treatment was not due to an increased uptake or to faster internalization kinetics of IT molecules in this cell population; rather, our data indicated that a different intracellular routing of IT molecules took place in the two cell populations. Mathematical modeling of experimental data allowed us to calculate the efficiency of the intracellular transport of IT molecules toward a subcellular compartment facilitating toxin translocation to the cell cytosol. The IT intracellular processing in stationary cells was 5.5-fold more efficient than in proliferating cells. This value strictly correlated with the higher sensitivity of the stationary cell population to ST.1-RTA treatment.
Regulation of expression of the IL-1 receptor antagonist (IL-1ra) gene by products of the human cytomegalovirus immediate early genes.
Authors: Kline J N , Geist L J , Monick M M , Stinski M F , Hunninghake G W 
Published: December 2022

Abstract
Human cytomegalovirus (HCMV), which is a major cause of morbidity and mortality in immunosuppressed patients, can itself alter immune function. It has previously been shown that HCMV immediate early (IE) gene products regulate the IL-1 beta promoter. The purpose of these studies was to determine whether HCMV IE gene products regulate expression of the IL-1 receptor antagonist (IL-1ra) gene. THP-1 cells, a myelomonocytic cell line, were transfected with a plasmid containing one or more of the HCMV IE genes downstream of the HCMV major immediate early promoter, or with a control plasmid. IL-1 beta and IL-1ra protein secretion was evaluated by ELISA, and expression of the mRNA for the cytokines was examined by means of Northern blot analysis. The HCMV IE1+2 gene products were found to increase expression of the mRNA for both IL-1 beta and IL-1ra; however, only the IL-1ra protein was released in increased amounts. The individual HCMV IE gene products had different effects on expression of the IL-1ra gene; the HCMV IE1 gene product down-regulated expression of the IL-1ra gene, whereas the IE2 gene product up-regulated expression of the IL-1ra gene. Thus, HCMV IE gene products can either up-regulate or down-regulate expression of the IL-1ra gene, depending on which IE genes are expressed in monocytes-macrophages. This study adds to the understanding of how HCMV can alter immune function during both active and latent infection.
The role of T cell activation in anti-CD3 x antitumor bispecific antibody therapy.
Authors: Weiner G J , Kostelny S A , Hillstrom J R , Cole M S , Link B K , Wang S L , Tso J Y 
Published: December 2022

Abstract
Anti-CD3 x antitumor bispecific Ab can retarget T cell mediated lysis in an MHC-independent fashion and prevent tumor growth in animal models. Two bispecific Ab preparations that differ in the presence or absence of Fc were compared in the 38C13 immunocompetent murine lymphoma model to evaluate how functional Fc and T cell activation impact on response to bispecific Ab therapy. Bispecific (bs) IgG contained functional Fc and was purified from hybrid-hybridoma Ab product. Bsf(ab')2 lacked functional Fc, and was genetically constructed using the leucine zipper technique. In vitro, bsF(ab')2 induced tumor cell lysis by activated T cells more effectively than bsIgG. However, bsF(ab')2 failed to induce T cell activation in the absence of tumor cells, and did so more slowly than bsIgG when tumor cells were present. In vivo, bsIgG induced nonspecific T cell activation whereas bsF(ab')2 did not. In therapy experiments, bsIgG inhibited tumor growth in mice although a single dose of bsF(ab')2 had minimal antitumor effect. BsF(ab')2 was capable of preventing tumor growth and improving survival when mice were also treated with T cell activators (IL-2 or staphylococcal enterotoxin B), or given repeated bsF(ab')2 doses. We conclude that therapeutic response to bispecific Ab was not dependent on functional Fc, but did require T cell activation. The use of bifunctional constructs that lack functional Fc therefore allows for separate manipulation of T cell retargeting and T cell activation and deserves further evaluation as a potential immunotherapy for malignancy.
Platelet-activating factor antagonist TCV-309 attenuates the induction of the cytokine network in experimental endotoxemia in chimpanzees.
Authors: Kuipers B , van der Poll T , Levi M , van Deventer S J , ten Cate H , Imai Y , Hack C E , ten Cate J W 
Published: December 2022

Abstract
Platelet-activating factor (PAF) has been postulated to play a role in the pathogenesis of sepsis. Additionally, in vitro studies have revealed tight interactions between PAF and the cytokine network, and PAF is considered to be an important stimulator of neutrophil functions. To assess the intermediate role of PAF in the induction of cytokines and neutrophil degranulation in endotoxemia in vivo, 12 healthy adult chimpanzees were i.v. injected with a bolus dose of Escherichia coli endotoxin (4 ng/kg); four animals received endotoxin alone, whereas the other chimpanzees were infused with the specific and potent PAF antagonist TCV-309 (bolus of 100 micrograms/kg, followed by either 100 micrograms/kg/h (n = 4) or 500 micrograms/kg/h (n = 4) for 5 h). At both doses TCV-309 significantly inhibited the endotoxin-induced rise in cytokine levels. Peak TNF concentrations after injection of endotoxin alone were 366 +/- 96 pg/ml, vs 105 +/- 47 and 115 +/- 56 pg/ml after administration of endotoxin together with the lower or higher dose of TCV-309, respectively (p &lt; 0.05). TCV-309 also reduced the appearance of soluble TNFRs. Maximal levels of the type I soluble TNFR were diminished from 2.53 +/- 0.27 ng/ml (endotoxin alone) to 1.69 +/- 0.36 ng/ml (high dose TCV-309; p &lt; 0.05); peak values of the type II soluble TNFR were diminished from 8.62 +/- 1.19 ng/ml to 5.76 +/- 0.92 ng/ml (p &lt; 0.05). Furthermore, TCV-309 attenuated the endotoxin-induced release of IL-6 (160 +/- 82 pg/ml after endotoxin alone, vs 63 +/- 30 pg/ml in the low dose TCV-309 group (p &lt; 0.05) and 65 +/- 29 pg/ml in the high dose group (p = 0.07) as well as that of IL-8 (279 +/- 168, vs 71 +/- 15 and 46 +/- 17 pg/ml, respectively; both p &lt; 0.05). TCV-309 tended to reduce the endotoxin-provoked rise in serum IL-1R antagonist levels. In contrast, TCV-309 did not affect the neutrophilic leukocytosis elicited by endotoxin, nor did it inhibit endotoxin-induced neutrophil degranulation, as monitored by the plasma levels of elastase-alpha 1-antitrypsin complexes. We conclude that PAF plays a role, either directly or indirectly, in the stimulation of the cytokine network and in the shedding of soluble TNFR in endotoxemia. PAF does not seem to be an important intermediate factor in endotoxin-induced neutrophilia or neutrophil degranulation.
Simian immunodeficiency virus as a model for vaccination against HIV. Induction in rhesus macaques of GAG- or NEF-specific cytotoxic T lymphocytes by lipopeptides.
Authors: Bourgault I , Chirat F , Tartar A , Lévy J P , Guillet J G , Venet A 
Published: December 2022

Abstract
The protection against infection by HIV probably requires the induction of both neutralizing Abs and CTL responses. Vaccination by attenuated HIV is hardly acceptable and the use of viral genes inserted in recombinant living vectors needs further development, especially with respect to safety. The peptidic vaccination is a promising approach but free peptides are usually poorly immunogenic. Because potent immune responses have been obtained in mice with modified peptides such as lipopeptides, we have designed a study to assess the immunogenicity of lipopeptides in nonhuman primates. Seven lipopeptides were synthesized, derived from known immunogenic regions of the simian immunodeficiency virus (SIV) NEF and GAG proteins. Twelve rhesus macaques, randomly chosen and not selected on their MHC basis, were immunized subcutaneously with the seven lipopeptides in IFA. An MHC class I-restricted and CD(8+)-mediated CTL response has been observed in seven macaques directed against one or two of the synthetic immunizing peptides in each case. These CTLs were able to lyse autologous target cells infected with a recombinant vaccinia virus expressing the SIV nef or gag genes, suggesting that they recognized the naturally processed peptides. These activities are detectable in peripheral blood cells for at least 10 mo after the last immunization. Abs against the immunizing peptides have also been observed in all cases. This study demonstrates that lipopeptides can generate cytotoxic and humoral immune responses in a large number of unselected animals and this approach may thus be worth considering in the vaccination against HIV.
Purification and characterization of Yersinia enterocolitica envelope proteins which induce antibodies that react with human thyrotropin receptor.
Authors: Luo G , Seetharamaiah G S , Niesel D W , Zhang H , Peterson J W , Prabhakar B S , Klimpel G R 
Published: December 2022

Abstract
Graves' disease is an autoimmune disease mediated by autoantibodies to the thyrotropin receptor (TSHR). Several studies have suggested that the development of Graves' disease may be linked to infection with the enteric pathogen Yersinia enterocolitica. Using the purified recombinant extracellular domain of human TSHR (ETSHR), we have recently shown that immunization of mice with Y. enterocolitica results in the production of antibodies capable of reacting with the ETSHR. In this study, we identify two low molecular weight (5.5 kDa and 8 kDa) envelope proteins of Yersinia containing epitopes that are crossreactive with the TSHR. Identification of these crossreactive envelope proteins was achieved by Western blotting using affinity-purified anti-Y. enterocolitica antibodies that specifically react with the TSHR and, conversely, for envelope proteins of Yersinia. Confirmation that these Yersinia proteins contained crossreactive epitopes with the ETSHR was obtained by immunizing mice with partially purified envelope proteins, which resulted in the production of Abs that recognized the ETSHR. Further, some of the cross-reactive envelope proteins were purified with SDS-PAGE and HPLC. The crossreactive envelope proteins were shown to be chromosomally encoded, exposed on the surface of bacteria, and produced by virulent as well as avirulent strains of Yersinia (Y. pestis, Y. pseudotuberculosis, Y. enterocolitica VW+, and Y. enterocolitica VW-). These results identify for the first time the Yersinia envelope proteins that are crossreactive with the ETSHR. Availability of these proteins will allow future studies to determine whether patients with Graves' disease have a unique immune response against these proteins when compared with healthy individuals.