bluuebunny/crossref_metadata_2025_split huggingface dataset:
Expression pattern of the most JH-proximal human VH gene segment (VH6) in the B cell and antibody repertoire suggests a role of VH6-encoded IgM antibodies in early ontogeny.
Authors: Van Es J H , Raaphorst F M , van Tol M J , Meyling F H , Logtenberg T 
Published: December 2022

Abstract
We have developed a mAb (JE-6) that recognizes an Id encoded by the most JH-proximal human VH gene segment (VH6) in or near germ-line configuration. This mAb was used to determine the frequency of Id JE6+ B cells in large collections of monoclonal EBV-transformed and short term B cell lines derived from fetal, neonatal, and adult lymphoid tissues. Moreover, we investigated the presence of Id JE-6+ Ig in sera from neonates and adults and determined the (auto)antigen binding properties of VH6-encoded IgM mAb. We detected a fivefold overrepresentation of VH6-expressing IgM producing B cells in fetal tissues, cord blood, and adult bone marrow relative to adult blood. In cord blood, but not in adult blood sera, germ-line VH6-encoded IgM molecules were readily detectable. IgM secreted by VH6-expressing B cell clones displayed highly conserved and virtually identical autoantigen binding properties, independent of the length and composition of the IgH chain CDR3 region and L chain isotype. Collectively, these results suggest that the VH6 gene and the antibodies it encodes play an important role in early human ontogeny.
Allergen-specific modulation of cytokine synthesis patterns and IgE responses in vivo with chemically modified allergen.
Authors: Gieni R S , Yang X , HayGlass K T 
Published: December 2022

Abstract
Hypersensitivity and IgE synthesis are highly dependent on the balance in which production of IL-4 and IFN-gamma is induced. An immunologic approach that alters the dominant pattern of cytokine synthesis and antibody production that is elicited after exposure to native allergen is described. High M(r), glutaraldehyde-polymerized OVA administered (i.p.) before or after immunization with unmodified OVA induces &gt; or = 95% inhibition of specific IgE synthesis concomitant with 300- to 800-fold increases in IgG2a production in C57BL/6 mice. These changes result from a genetically controlled shift in the pattern of cytokine production within the allergen-specific T cell repertoire as demonstrated by i) susceptibility of the changes induced upon administration of modified allergen to in vivo treatment with anti-IFN-gamma mAb and ii) a 5- to 7-fold increase in the ratio of IFN-gamma:IL-4 synthesis after overnight culture directly ex vivo. This system should prove useful in identification of the factors which are influential in the commitment of T cells to Th1- or Th2-like patterns of cytokine synthesis. Moreover, as defective induction of IFN-gamma by allergen-specific T cells appears to play a role in elevated IgE synthesis and human allergy, this approach may have therapeutic potential.
Fresh and cultured Langerhans cells display differential capacities to activate hapten-specific T cells.
Authors: Dai R , Grammer S F , Streilein J W 
Published: December 2022

Abstract
Langerhans cells (LC) that have been cultured for 3 days acquire potent T cell-activating properties when compared to freshly prepared, uncultured LC. By contrast, fresh LC are superior to cultured LC in the ability to process native protein Ag. To define further the disparate functional properties of these epidermally derived APC, freshly isolated and cultured epidermal cells (EC) enriched for LC were prepared from BALB/c mice. Highly purified T cells from naive mice, and from mice sensitized epicutaneously with dinitrofluorobenzene, have been examined for their capacity to respond to fresh and cultured EC; 1) in the presence of staphylococcal enterotoxin B; and 2) after the EC had been derivatized with dinitrofluorobenzene. Both fresh and cultured EC activated syngeneic T cells in the presence of staphylococcal enterotoxin B, and fresh and cultured DNP-derivatized EC induced proliferation among DNP-specific T cells. Only cultured, hapten-derivatized EC were able to activate unprimed syngeneic T cells in vitro, and these cells responded as though "primed" when re-exposed to DNP-derivatized spleen cells in secondary cultures. In addition, naive lymphocytes that were activated by cultured DNP-EC were able to evoke local contact hypersensitivity reactions when injected into the pinnae of naive mice that were then painted with dinitrofluorobenzene. By contrast, naive syngeneic T cells exposed to fresh DNP-EC neither proliferated nor differentiated into effector cells. We conclude that fresh LC can constitutively activate primed, but not unprimed, hapten-specific T cells, whereas cultured LC readily both primed and unprimed T cells. The capacity of hapten-derivatized cultured EC to convert naive, hapten-specific T cells into cells that mediate contact hypersensitivity supports the proposal that cultured LC are the functional equivalents of epidermal LC that have migrated to draining lymph nodes. The ability of hapten-derivatized fresh LC to activate primed, hapten-specific T cells is consistent with the view that fresh LC are functionally equivalent to LC within the epidermis.
Delimitation of the proliferative stages in the human thymus indicates that cell expansion occurs before the expression of CD3 (T cell receptor).
Authors: Alvarez-Vallina L , González A , Gambón F , Kreisler M , Díaz-Espada F 
Published: December 2022

Abstract
Precursor of T lymphocytes undergo proliferation and maturation under the influence of the thymic microenvironment. In our study, we have attempted to determine the distribution of human postnatal thymocytes in division according to their stage of differentiation. Our data show that about 11.5% of all thymic cells are in S/G2/M phases, and that a subset of the cortical and precortical subpopulations contains most of the dividing cells. Rate of cell division is maintained at high levels from the prethymocyte precursor along the successive stages of differentiation represented by CD1+CD3-CD4-CD8- and CD1+CD3-CD4+CD8- cells. The percentage of dividing cells is maximal in an intermediate subset of CD1+CD3-CD4+CD8-CD45RO+ cells defined by the distinct expression of class I HLAdim/high molecules, which could contain cells in transit from prethymocytes to double-positive cortical cells. The CD3- fraction of the double-positive cortical cells contains most of the dividing thymocytes, although the rate of division within this subset is much less than that of the precursor CD1+CD3-CD4+CD8- cells. In a linear scheme of differentiation, cell division stops at or near the point of initiation of CD3 expression. These results suggest that in human thymus cell expansion takes place before the initiation of the positive selection process. According to this view the stringency of the selection process would require the previous generation of a large number of precursors to permit the production of sufficient numbers of mature T cells.
Disulfide linkage between C3b and tetanus toxin on tetanus toxin-specific EBV-transformed B cells.
Authors: Jacquier M R , Gabert F M , Villiers C L , Colomb M G 
Published: December 2022

Abstract
EBV-transformed B cells specific for tetanus toxin were found to bind C3b in excess over the expected figures based on the number of complement receptors CR1. This was confirmed by analysis of cell extracts by SDS-PAGE giving evidence for C3b-membrane protein complexes that were disrupted upon reduction. Alkylation of C3b-free cysteine abolished formation of these complexes and only a noncovalent binding of C3b to CR1 was observed, which could be inhibited by mAb to CR1. When C3b was incubated with the same cells coated with tetanus toxin bound to their specific membrane Ig, preferential formation of disulfide-bonded complexes between tetanus toxin and C3b was observed. These observations correspond to a novel capacity of C3b to interact covalently through its cysteine 1010 with free SH groups of protein acceptors. One hypothesis is that the disulfide bond formation is catalyzed by a thioredoxin-like protein secreted and expressed on the membrane of EBV-transformed B cells. In the context of Ag processing and presentation by B cells, disulfide binding of chaperone C3b to Ag is likely to persist during transcytosis and to play a significant role in the modulation of the processing.
Bone marrow-derived dendritic epidermal T cells express T cell receptor-alpha beta/CD3 and CD8. Evidence for their extrathymic maturation.
Authors: Shiohara T , Moriya N , Hayakawa J , Arahari K , Yagita H , Nagashima M , Ishikawa H 
Published: December 2022

Abstract
The majority of murine Thy-1+ dendritic epidermal T cells (DETC) express virtually identical TCR encoded by V gamma 5 and V delta 1 genes and are derived from early fetal thymic precursors. However, not consistent with this notion is an early finding that DETC arise continuously from bone marrow (BM) precursors by a thymus-independent mechanism. To address this issue, donor-type DETC were characterized in lethally irradiated mice that were reconstituted by Thy-1-disparate BM cells with or without a thymus. The BM-derived DETC, unlike their normal TCR-gamma delta counterparts, were found to express the TCR-alpha beta/CD3 complex and CD8, and their migration to the epidermis dermis occurred independently of the thymus. The numbers of the BM-derived DETC increased with time and reached a plateau 6 mo after BM transfer, at which time the TCR-alpha beta/CD3 complex was expressed on a small fraction of the DETC in athymic BM chimeras. Although no further increase in the number was observed at later times, at 1 yr after transfer most of the BM-derived DETC came to express the TCR-alpha beta/CD3 complex in the absence of thymic influence. By contrast, most of BM-derived T cells in other lymphoid organs from athymic BM chimeras still failed to express the TCR-alpha beta/CD3 complex even at 1 yr after transfer. These results suggest that extrathymic differentiation of BM-derived DETC could occur with the epidermal microenvironment.
Role of CD8 in staphylococcal enterotoxin B-mediated lysis by cytotoxic T lymphocytes.
Authors: Hoo W S , Kranz D M 
Published: December 2022

Abstract
Recent evidence has suggested that recognition of superantigens such as the staphylococcal enterotoxins by CTL occurs independently of the accessory molecule CD8. These conclusions are based on the observation that antibodies to CD8 do not appear to be effective inhibitors of T cell lysis that is mediated by enterotoxin. This is in contrast to the well-known inhibitory effects of anti-CD8 antibodies on T cell activation by most peptide/class I complexes. In this study, we show that lysis of staphylococcus enterotoxin B (SEB)-bearing target cells by the mouse alloreactive CTL clone 2C is inhibited by anti-CD8 antibodies. SEB-mediated lysis by a polyclonal population of mouse CTL was also inhibited by anti-CD8 antibodies, but only under conditions where the SEB concentration is low. Inhibition occurs even when class I negative Daudi cells are used as targets. Thus, the observed inhibition does not appear to be due to the prevention of intercellular interactions between CD8 and class I molecules but is probably a consequence of preventing the intracellular association of CD8 and TCR. At the high ligand densities used in most previous studies, very few of the CD8/TCR complexes may be required for activation. Under these conditions, lysis may appear to be CD8 "independent" because 1) there are a sufficient number of preexisting CD8/TCR complexes for activation; or 2) prohibitively high concentrations of antibody would be needed to saturate unassociated CD8.
Ca2+ ionophore A23187-dependent stabilization of granulocyte-macrophage colony-stimulating factor messenger RNA in murine thymoma EL-4 cells is mediated through two distinct regions in the 3'-untranslated region.
Authors: Iwai Y , Akahane K , Pluznik D H , Cohen R B 
Published: December 2022

Abstract
We analyze the role of the Ca2+ ionophore A23187 in the induction of GM-CSF mRNA expression in EL-4 thymoma cells. Northern analysis shows that A23187 increases the half-life of GM-CSF mRNA. To identify potential Ca2+ response elements in the GM-CSF mRNA, we produced stable transfectants containing pRSV-CAT (EL-4cat) or hybrid constructs in which most of the GM-CSF 3'-untranslated region (EL-4gm) or the adenosine-uridine boxes alone (EL-4au) were placed in a downstream position from the CAT coding region. A23187 induces a 4.4-fold increase in CAT activity in EL-4cat cells and a 210-fold and 48-fold increase in CAT activity in EL-4gm and EL-4au cells, respectively. Actinomycin D chase experiments in transfected cells demonstrate that A23187 increases the half-life of CAT mRNA from 15 min to 3 h in EL-4au cells and more than 3 h in EL-4gm cells, suggesting that the effect of Ca2+ is mediated predominantly by the adenosine-uridine boxes with a smaller contribution from upstream regions. To map these upstream regions, we transfected cells with constructs containing mutations of the 3'-untranslated region. With two of these mutations, corresponding to a region located about 160 bases upstream of the adenosine-uridine boxes, CAT activity was induced only 50-fold compared to 200-fold in EL-4gm cells. These data indicate that two regions within the GM-CSF 3'-untranslated region interact to modulate Ca2+ effects on GM-CSF mRNA half-life.
Different effects of substitutions at residues 224 and 228 of MHC class I on the recognition of CD8.
Authors: Sekimata M , Tanabe M , Sarai A , Yamamoto J , Kariyone A , Nakauchi H , Egawa K , Takiguchi M 
Published: December 2022

Abstract
Previous studies indicated that weak xenoresponse to HLA class I by mouse T cells is due to the inefficient interaction of mouse CD8 with the alpha 3 domain of HLA class I. The present study using chimeric H-2Kb molecules with recombinant alpha 3 domain between H-2Kb and HLA-B7 as well as single amino acid mutants of H-2Kb demonstrated that each substitution at residues 224 and 228 affects recognition of CD8-dependent mouse CTL clones. On the other hand, reactivity of IL-2-producing H-2Kb-specific T cell hybridoma transfected with mouse CD8 alpha was abrogated by substitution at residue 224 but not by that at residue 228. This indicates that the substitution at residue 228 affects recognition of CD8-dependent CTL but does not critically affect binding of CD8 to MHC class I molecules, although residue 224 abrogates binding of CD8. The model structure of the alpha 3 domain of H-2Kb suggests that the substitution at residue 224 induces conformational change of CD8 binding loop, whereas minimum structure change by the substitution at residue 228 is expected. It is therefore speculated that minimum structure change of CD8 binding loop by substitution at residue 228 may influence binding affinity of CD8, which abrogates recognition of CD8-dependent CTL but not IL-2 production of the CD8-dependent T cell hybridoma.
Human monoclonal antibody HA-1A binds to endotoxin via an epitope in the lipid A domain of lipopolysaccharide.
Authors: Bogard W C , Siegel S A , Leone A O , Damiano E , Shealy D J , Ely T M , Frederick B , Mascelli M A , Siegel R C , Machielse B 
Published: December 2022

Abstract
HA-1A, a human IgM mAb, has been shown to significantly reduce mortality in septic patients with Gram-negative bacteremia, especially those with septic shock, in a controlled clinical trial. To confirm the reported specificity of this antibody for the lipid A domain of endotoxin, several assay systems were developed. These assay systems included an ELISA, which measured the binding of HA-1A to lipid A adsorbed to a solid phase; a rate nephelometry assay, which measured the ability of HA-1A to bind and aggregate lipid A in solution; and a dot-blot immunoassay, which measured the ability of HA-1A to interact with lipid A adsorbed to Immobilon-P. In all three assay systems, HA-1A bound in a dose-dependent manner to lipid A prepared from Salmonella minnesota R595 LPS, whereas negative control human IgM mAb or polyclonal antibodies did not. Several experimental approaches were employed to demonstrate the specificity of HA-1A in these assay systems. Both polymyxin B and murine IgG mAb (8A1) with a specificity for lipid A were able to competitively inhibit HA-1A reactivity with lipid A in a dose-dependent manner. Furthermore, a murine IgG anti-Id mAb (9B5.5) developed against HA-1A was also able to block the binding of HA-1A to lipid A in these assay formats. HA-1A reactivity with synthetic lipid A confirmed that HA-1A binding to the natural lipid A was not the result of contaminants in the latter. Finally, the reactivity of HA-1A against a variety of glucosamine-containing and fatty acid-containing compounds was assessed. Some weak interaction was seen with cardiolipin and chitin, but not with serum proteins, lipoteichoic acid, or DNA. Collectively, these results conclusively establish that HA-1A binds to the lipid A region of LPS by an interaction with the V region of the antibody.
Substance P selectively activates TNF-alpha gene expression in murine mast cells.
Authors: Ansel J C , Brown J R , Payan D G , Brown M A 
Published: December 2022

Abstract
There is increasing evidence that the neurologic system is capable of modulating a wide range of immunologic responses, including certain inflammatory processes in the lung, gastrointestinal tract, and skin. It has been proposed that secreted neuropeptides such as substance P (SP) may mediate these neuroinflammatory interactions by binding to and stimulating immune cells such as mast cells and lymphoid cells. SP is secreted in a variety of tissues by an extensive network of neurosensory C and A5 fibers in response to a wide range of noxious stimuli and injury. Previous studies to examine the effect of SP on mast cells have focused on its role in triggering histamine release and mediating immediate hypersensitivity responses. Recently it was demonstrated that mast cells are also capable of secreting multiple cytokines including TNF-alpha, IL-1, IL-3, IL-4, IL-6, and GM-CSF. In this study we tested the possibility that SP may also influence mast cell-mediated late inflammatory events by modulating the production of one or several of these cytokines. Our results indicate that SP induces TNF-alpha mRNA expression and TNF-alpha secretion in a dose-dependent manner in a murine mast cell line, CFTL12. Likewise, SP stimulates TNF-alpha secretion in freshly isolated murine peritoneal mast cells. The induction of mast cell TNF-alpha is selective, since SP does not stimulate the production of IL-1, IL-3, IL-4, IL-6, or GM-CSF in these cells. The CFTL 12 mast cell line constitutively expresses high levels of SP receptor mRNA which is not modulated by PMA/cycloheximide treatment or SP. These results further support the concept that the neurologic system modulates inflammatory events by neuropeptide-mediated mast cell cytokine release.
Transforming growth factor-beta inhibits E-selectin expression on human endothelial cells.
Authors: Gamble J R , Khew-Goodall Y , Vadas M A 
Published: December 2022

Abstract
Transforming growth factor-beta (TGF-beta), a pleiotropic cytokine that is elaborated in the active form upon co-culture of endothelial cells and pericytes or smooth muscle cells, has been shown to decrease the adhesiveness of endothelial cells for neutrophils, lymphocytes, and tumor cells. The mechanism whereby TGF-beta inhibits the adhesiveness of human endothelial cells was investigated. TGF-beta inhibited the basal E-selectin (formerly ELAM-1) expression by 55 +/- 7% and TNF-stimulated expression by 57 +/- 4%. Similar decreases of IL-1-stimulated expression were also seen. Peak inhibition was seen at TGF-beta doses between 0.2 and 2 ng/ml. Both TGF-beta 1 and -beta 2 were functional. The effectiveness of TGF-beta in inhibiting E-selectin expression was dependent on cell density and incubation time. TGF-beta also inhibited E-selectin mRNA levels in endothelial cells. TGF-beta had no effect on the expression of VCAM-1 and ICAM-1, but was additive with IL-4 in inhibiting the expression of E-selectin. The expression of E-selectin has been shown to mediate several aspects of the inflammatory response involving neutrophils and memory T lymphocytes. Perivascular TGF-beta appears to act as an inhibitor of the expression of the endothelium-specific selectin, E-selectin, and therefore of inflammatory responses involving neutrophils and (a subset of) lymphocytes.
Increased Fc alpha R expression and IgA-mediated function on neutrophils induced by chemoattractants.
Authors: Hostoffer R W , Krukovets I , Berger M 
Published: December 2022

Abstract
The recent reports of receptors for IgA on blood and mucosal phagocytes suggest a more active role then previously thought for IgA in host defense. Using a mAb and flow cytometry we determined the expression of the Fc alpha R on resting and chemoattractant-stimulated blood neutrophils and compared them with mucosal neutrophils. Fc alpha R expression on blood neutrophils could be rapidly up-regulated in vitro, increasing three to fourfold within minutes of exposure to the chemoattractants FMLP (optimal at 10(-8) M) and zymosan activated serum (a source of C5a). The level of Fc alpha R expression found on neutrophils obtained from bronchoalveolar lavage of cystic fibrosis patients with chronic lung infection was almost identical to that found on blood neutrophils from the same patients maximally activated in vitro. The rise in Fc alpha R expression induced by 10(-8) M FMLP was rapid, with a plateau in 15 to 20 min, and was not inhibited by 10 mg/ml of cycloheximide or puromycin, suggesting that the mechanism of up-regulation involves translocation from intracellular storage pools. Ionomycin (2 mM) plus 1.2 mM CaCl2 also increased expression of Fc alpha R, and its effects were inhibited by EDTA. Trifluoperazine, an inhibitor of calmodulin and/or protein kinase C-dependent processes, blocked the increase in Fc alpha R expression induced by FMLP, but the effects of the chemoattractant were not blocked by EDTA, suggesting that intracellular stores of calcium are important in the physiologic regulation of Fc alpha R expression. Neutrophil superoxide production could be induced by aggregated IgA, and was increased if the neutrophils were pretreated with FMLP, correlating with the increase in Fc alpha R expression. The superoxide response to a suboptimal dose of aggregated IgG was unaffected by FMLP pretreatment, and antibodies to Fc gamma R failed to block the superoxide production induced by IgA. Thus, the increase in phagocyte surface expression of Fc alpha R induced by chemoattractants in vitro and on mucosal cells in vivo, and the concomitant increase in IgA-mediated function may greatly facilitate the defense of mucosal surfaces.