bluuebunny/crossref_metadata_2025_split huggingface dataset:
Murine KIT+ lineage- bone marrow progenitors express Fc gamma-RII but do not express Fc epsilon-RI until mast cell granule formation.
Authors: Lantz C S , Huff T F 
Published: December 2022

Abstract
We examined the expression of Fc epsilon-RI and Fc gamma-RII/III on mouse bone marrow cells enriched for hematopoietic progenitors including mast cell progenitors. Bone marrow cells were depleted of mature hematopoietic lineages and a primitive population of cells that express the proto-oncogene c-kit (KIT+ lineage- cells) was isolated. KIT+ lineage- cells stain positively using the Ab 2.4G2, indicating surface expression of Fc gamma-RII and/or Fc gamma-RIII. Fluorescent staining of intracytoplasmic domains of Fc gamma-RII and Fc gamma-RIII revealed that these cells express primarily Fc gamma-RII on their surface. KIT+ lineage- cells did express Fc gamma RIII alpha-chain protein, but predominately in the nuclear/perinuclear area. We could not detect surface expression of Fc epsilon-RI by KIT+ lineage- cells, although a heterogeneous population of KIT- cells does bind IgE with high affinity and may reflect cells of the basophilic lineage. KIT+ lineage- cells cultured with SCF and IL-3 generate numerous mast cells, whereas equivalent numbers of KIT- cells or naive bone marrow cells do not. In these cultures, surface expression of Fc epsilon-RI is detected on a small number of cells by day 3 of culture with increased surface expression levels correlating roughly with metachromatic granule formation. The fact that Fc gamma-RIII and Fc epsilon-RI are not expressed on the cell surface of KIT+ lineage- cells but appear later in hematopoietic development makes it unlikely that these receptors influence early hematopoietic differentiation. The role that might justify such a complete surface expression of Fc gamma-RII by bone marrow progenitors remains to be identified.
Constitutive expression of human hsp27, Drosophila hsp27, or human alpha B-crystallin confers resistance to TNF- and oxidative stress-induced cytotoxicity in stably transfected murine L929 fibroblasts.
Authors: Mehlen P , Preville X , Chareyron P , Briolay J , Klemenz R , Arrigo A P 
Published: December 2022

Abstract
Hyperthermia and other forms of stress that induce and/or stimulate heat shock or stress protein (hsp) expression enhance the cellular resistance to TNF-alpha. One of the stress proteins, hsp70, has been shown to participate in the molecular mechanisms that regulate this phenomenon. Here we have tested the capability of small hsps from different species to protect against this cytokine in the TNF-sensitive L929 fibrosarcoma cells. The genes that encode human hsp27, Drosophila hsp27, and human alpha B-crystallin were placed under the control of the constitutive SV40 early promoter and were stably introduced into L929 cells. We observed that all clones that constitutively expressed the exogenous small hsps exhibited a strong protection against TNF-mediated killing, which was proportional to the level of the expressed proteins. This phenomenon did not correlate with altered binding of TNF-alpha to its receptors, and no protection was observed as a consequence of the transfection or selection procedures. In addition, the overexpression of the exogenous small hsps did not modify the level of the endogenous stress proteins in the transfected clones. Remarkably, the small hsps also induced a protection against oxidative stresses generated by either hydrogen peroxide or menadione. In L929 cells, the killing induced by TNF-alpha and oxidative stress is thought to occur through the accumulation of intracellular reactive oxygen intermediates. Hence, our data suggest that the small hsps from different species share the property to protect L929 cells against the deleterious effects of reactive oxygen intermediates generated by either TNF-alpha or oxidative stress.
Ig-binding surface proteins of Streptococcus pyogenes also bind human C4b-binding protein (C4BP), a regulatory component of the complement system.
Authors: Thern A , Stenberg L , Dahlbäck B , Lindahl G 
Published: December 2022

Abstract
Streptococcus pyogenes, an important human pathogen, expresses several proteins that interact with the immune system of the host. Among the proteins isolated from different bacterial strains are antiphagocytic M proteins, Ig Fc-binding proteins and exotoxins that act as superantigens. Here we report a novel interaction between S. pyogenes and the human immune system, the ability of most S. pyogenes strains to bind human C4BP (C4b-binding protein), a 570-kDa serum protein that inhibits the classical pathway of complement activation. Molecular analysis of three different streptococcal strains demonstrated that C4BP binds to protein Arp or protein Sir, two Ig-binding cell surface molecules that are members of the M protein family. These bacterial proteins have separate high affinity binding sites for Ig and for C4BP, as demonstrated by inhibition tests and binding assays with purified components. A single streptococcal cell surface molecule, Arp or Sir, therefore combines the abilities to bind Ig and C4BP, two high m.w. components of the immune system. Two bacterial strains expressing Arp or Sir were shown to selectively bind C4BP in whole human serum, suggesting that S. pyogenes also binds C4BP in the infected host. When bound to streptococcal cells, C4BP retained its ability to act as a cofactor in the degradation of C4b by factor I. These results indicate that many strains of S. pyogenes interfere with the classical pathway of complement activation by binding C4BP to the bacterial cell surface.
HIV-1 infection alters monocyte interactions with human microvascular endothelial cells.
Authors: Dhawan S , Weeks B S , Soderland C , Schnaper H W , Toro L A , Asthana S P , Hewlett I K , Stetler-Stevenson W G , Yamada S S , Yamada K M 
Published: December 2022

Abstract
HIV infection of monocytes resulted in twofold elevation of adhesion molecule LFA-1 (both alpha L/CD11a and beta 2/CD18 subunits) and LFA-3 (CD58), with no apparent increase in LFA-2 (CD2) or various beta 1-integrins. Homotypic aggregation of monocytes was evident 2 h after exposure to virus and was inhibited by mAbs to both the alpha L- and beta 2-subunits of LFA-1. HIV-infected monocytes also showed a marked increase in adherence to human capillary endothelial cell monolayers derived from brain, lung, and skin. This adherence was inhibited by mAb to either LFA-1 subunit and by mAb to the counter-receptor intercellular adhesion molecule-1. Cocultivation of HIV-infected monocytes with endothelial cells increased permeability of endothelial cell monolayers to 125I albumin in transwell assay systems. The increased endothelial permeability induced by HIV-infected monocytes was associated with a substantial disruption of the endothelial cell monolayer. Morphologic disruption was not a direct toxic effect on endothelial cells, but appeared to be secondary to changes in endothelial cell-cell or cell-matrix interactions. Northern blot analysis showed increased expression of gelatinase B (92-kDa gelatinase), tissue inhibitor of metalloproteinase TIMP-1, and TIMP-2 in the HIV-infected monocytes. Consistent with these Northern analyses, secretion of gelatinase activity in culture fluids of HIV-infected monocytes was also increased and was dependent on the stage of virus replication. Incubation of HIV-infected monocytes with the proteinase inhibitors TIMP-1 and TIMP-2 inhibited the increased permeability of endothelial cell monolayers to 125I albumin. These results suggest possible mechanisms for extravasation of HIV-infected monocytes through vascular endothelium into tissue in early stages of HIV disease.
Enhanced production of TGF-beta by blood monocytes from patients with active tuberculosis and presence of TGF-beta in tuberculous granulomatous lung lesions.
Authors: Toossi Z , Gogate P , Shiratsuchi H , Young T , Ellner J J 
Published: December 2022

Abstract
The expression of TGF-beta, a molecule that affects both immune responsiveness and wound healing, was examined in blood monocytes and granulomatous lesions from patients with active pulmonary tuberculosis. The spontaneous release of TGF-beta was higher in culture supernatants of monocytes from patients as compared with those of healthy subjects by an ELISA (p &lt; 0.0005). TGF-beta activity was also confirmed in a bioassay in supernatants from patients. Next, freshly isolated monocytes from patients with tuberculosis and matched subjects were examined for TGF-beta activity. Cytosmears of monocytes were stained with an Ab against TGF-beta 1 (anti-LC) or isotype-specific Ab by using an alkaline-phosphatase anti-alkaline phosphatase method. In contrast to monocytes from healthy individuals, 60 to 70% of monocytes from patients demonstrated cytoplasmic staining for TGF-beta (n = 3). Upon hypotonic lysis, monocytes from patients with tuberculosis contained immunoreactive TGF-beta (n = 3). By Northern blot analysis, monocytes from three of seven patients with tuberculosis had increased expression of TGF-beta mRNA as compared with concurrently examined monocytes from healthy subjects. Within the granulomas of lung sections from two patients with untreated tuberculosis, TGF-beta immunoreactivity was identified in the Langhan's giant cells mainly and to a lesser extent the epithelioid cells using anti-LC Ab and the peroxidase-anti-peroxidase technique. Thus, both blood monocytes and lung granuloma macrophages from patients with active tuberculosis express TGF-beta. Excess activity of this cytokine in blood monocytes may underlie the depressed T cell responses of patients with tuberculosis. Moreover, within the infected tissues excess TGF-beta activity may interfere with anti-mycobacterial mechanisms and effective granuloma formation.
Regulation of differentiation of peritoneal B-1a (CD5+) B cells. Activated peritoneal macrophages release prostaglandin E2, which inhibits IgM secretion by peritoneal B-1a cells.
Authors: Chace J H , Fleming A L , Gordon J A , Perandones C E , Cowdery J S 
Published: December 2022

Abstract
The B-1a (CD5+) subset of B cells comprises the majority of B cells in the peritoneal cavity and is implicated in the pathogenesis of certain autoimmune diseases and lymphoproliferative disorders. When we stimulated purified B-1a cells with LPS, they produced more than four times as much IgM as similarly stimulated whole peritoneal cells (containing the same number of B-1a cells). Reconstitution experiments using FACS-purified peritoneal cell populations revealed that resident peritoneal macrophages (Mac1+, B220-) profoundly inhibited the LPS response of peritoneal B-1a cells. Culture of B-1a cells with peritoneal macrophages at a ratio of 3:1 (reflecting the in vivo ratio) resulted in a fivefold or greater reduction in the IgM response to LPS. LPS activation of macrophages resulted in production of a soluble factor that inhibited LPS-induced B cell differentiation by 86% when used at a concentration of 5%. When [3H]arachidonic acid-pulsed macrophages were stimulated with LPS, the major arachidonic acid metabolite secreted was PGE2 (a potent inhibitor of B cell differentiation). The inhibitory capacity of the macrophage-derived supernatant was reversed by the addition of anti-PGE2. These findings indicate that macrophage-derived PGE2 functions as an important regulator of polyclonal response of B-1a cells to LPS.
T cell development in insulin-like growth factor-II transgenic mice.
Authors: Kooijman R , van Buul-Offers S C , Scholtens L E , Schuurman H J , Van den Brande L J , Zegers B J 
Published: December 2022

Abstract
Growth hormone and insulin-like growth factor-I (IGF-I) have been demonstrated to play a role in T and B cell development. We studied the effects of IGF-II on T cell development in two transgenic mouse lines that overexpress human IGF-II under the control of the H2Kb promoter. The thymuses of 1-wk-old mice of two transgenic lines (5'-35 and 5'-74) contained 36 and 68%, respectively, more thymocytes than controls. Between 1 and 4 wk of age, the overexpression of IGF-II also resulted in a 2 to 2.5 times stronger increase in thymic cellularity. As in control mice, the number of thymocytes declined after 4 wk of age, and at 15 wk it was no longer significantly different from controls. Flowcytometric analysis indicated that at 2 and 4 wk of age, the increased thymic cellularity was associated with an increased number of early (CD4- CD8- or CD4- CD8dim), intermediate (CD4+CD8+), and mature thymocytes (CD3++CD4+CD8- or CD3++CD4-CD8+). However, the increase in the number of CD4+CD8- thymocytes was larger than the increase in the number of CD4-CD8+ thymocytes. As a consequence, CD4+ T cells mainly contributed to the increase in the number of T cells in spleen. These T cells showed a mature phenotype since they expressed CD3 and were negative for heat-stable antigen, a marker for immature T cells. These data indicate that overexpression of IGF-II increases thymic cellularity and stimulates the generation of phenotypically normal T cells with a preference to CD4+ cells.
Analysis of the normal human IgG antibody repertoire. Evidence that IgG autoantibodies of healthy adults recognize a limited and conserved set of protein antigens in homologous tissues.
Authors: Mouthon L , Haury M , Lacroix-Desmazes S , Barreau C , Coutinho A , Kazatchkine M D 
Published: December 2022

Abstract
We have used a quantitative immunoblot technique to analyze the Ab repertoire of IgG in the serum of healthy adults with a large panel of homologous and foreign Ags in tissue extracts. Densitometric patterns of reactivity of purified IgG with self-Ags exhibited striking homogeneity among individuals with regard to the protein bands that were recognized. Purified IgG showed higher levels of reactivity with self-Ags than IgG in whole serum. Reactivity with self-Ags of IgG in whole serum was restricted to a small number of protein bands (fewer than 10). There were significant inter-individual differences in the intensity and nature of immunoreactivities. Purified IgG of different individuals exhibited heterogeneous patterns of immunoreactivity with Ags in bacterial extracts. Comparative analysis of repertoires of IgG and IgM indicated that all protein Ags recognized by IgM were also reactive with purified IgG. Some proteins in homologous and in foreign tissue extracts reacted solely with IgG. Our observations provide direct evidence for the restricted and conserved character of the antiself-repertoire of IgG of healthy adults and suggest that natural IgG Ab repertoires in serum are specifically selected for reactivity with a limited set of self-Ags. In addition, IgG autoreactivity in whole serum is controlled by non-IgG factors that determine the unique reactivity pattern of each individual.
Functional ambivalence of the Kp43 (CD94) NK cell-associated surface antigen.
Authors: Pérez-Villar J J , Melero I , Rodríguez A , Carretero M , Aramburu J , Sivori S , Orengo A M , Moretta A , López-Botet M 
Published: December 2022

Abstract
We originally characterized the Kp43 (CD94) surface Ag, whose expression is restricted to human NK cells and a minor T lymphocyte subset. As shown in the present study, anti-Kp43 mAbs but not their F(ab')2 fragments markedly inhibited the cytolytic activity of polyclonal-activated NK cells in a redirected lysis assay against the murine P815 cell line. Furthermore, anti-Kp43 mAbs also down-regulated the CD16-dependent redirected killing and PHA-induced lectin-dependent cellular cytotoxicity. However, the intensity of the inhibitory effect was variable and no significant down-regulation of cytotoxicity was substantiated in NK cell populations from some individuals. A similar variability in the responsiveness to anti-Kp43 mAb was noticed when fresh CD3- lymphocyte populations were tested: in some donors we observed the induction of redirected lysis, whereas in other samples the Kp43-specific mAb inhibited cytotoxicity. The analysis of single cell-derived microcultures provided a clue to interpret the variable responsiveness of polyclonal cell populations; remarkably, the cytolytic activity of some NK clones was inhibited, whereas that of others was either stimulated or unaffected. The pattern of responsiveness in the cytolytic assay correlated with TNF production upon stimulation with solid phase-bound anti-Kp43 mAbs. The different types of clones could be derived from the same individual, although their relative proportions varied from donor to donor. Moreover, Kp43 appeared to be coupled differently to signal transduction pathways, because (Ca2+)i mobilization in the presence of the Kp43-specific mAbs was substantiated only in clones that were activated in the redirected lysis assay.
A protease-dependent TCR-induced death pathway in mature lymphocytes.
Authors: Sarin A , Nakajima H , Henkart P A 
Published: December 2022

Abstract
Several cysteine and serine protease inhibitors previously shown to block TCR-induced death of 2B4 T hybridoma cells were tested for their ability to block various T lymphocyte apoptotic death systems. TCR-induced death of both peripheral CD4+ and CD8+ T cell blasts was inhibited similarly to the hybridoma, but cell death in these cells induced by anti-Fas, gamma-irradiation, etoposide, or extracellular ATP was not blocked. For T cell lines, cell death induced by CTL or by IL-2 withdrawal was also not inhibited. TCR-induced death of immature CD+8+ thymocytes triggered by culture on immobilized anti-CD3 was not blocked by these protease inhibitors, whereas similar death induced in the resting CD4+8- thymocyte subset under these conditions was inhibited similarly to the T cell blasts. TCR-induced proliferation of the latter subset was modest in the absence of exogeneous IL-2, but was enhanced two- to fourfold by the protease inhibitors. These results show that a protease-dependent death pathway can be triggered by the TCR in mature T cells; similar protease-dependent steps are not common to the TCR-triggered activation pathway or other apoptotic death pathways in these cells.
IL-3 and granulocyte-macrophage colony-stimulating factor strongly induce Ig secretion by sort-purified murine B cell activated through the membrane Ig, but not the CD40, signaling pathway.
Authors: Snapper C M , Moorman M A , Rosas F R , Kehry M R , Maliszewski C R , Mond J J 
Published: December 2022

Abstract
Sort-purified resting murine B cells proliferate in response to dextran-conjugated anti-IgD Abs (alpha delta-dex) but fail to secrete significant amounts of Ig even after the addition of IL-1 + IL-2. We show that either IL-3 or granulocyte-macrophage CSF (GM-CSF) stimulates 10- to 50-fold enhancements in IgM secretion by sort-purified B cells treated with alpha delta-dex + IL-1 + IL-2, and that the combined actions of IL-3 and GM-CSF are typically greater than additive. Both IL-3 and GM-CSF act primarily as B cell differentiation factors, although IL-3 induces a modest enhancement in cellular outgrowth. The enhancing effects of IL-3 and GM-CSF require multivalent Ag receptor cross-linkage, mediated by alpha delta-dex, as neither cytokine induces IgM secretion in the presence of unconjugated anti-IgD Abs. Although both alpha delta-dex and IL-1 + IL-2 are required for optimal IL-3- and GM-CSF-mediated IgM secretion, both IL-3 and GM-CSF stimulate a modest IgM secretory response by cells activated with alpha delta-dex alone. In this regard, supernatant from either an activated CD4+ Th1 or Th2 clone potently induces IgM secretion by alpha delta-dex + IL-1 + IL-2-activated B cells and this is due, in large part, to the presence in these supernatants of either IL-3 and/or GM-CSF. Neither IL-3 nor GM-CSF stimulates significant IgM secretion by B cells activated through the CD40 signaling pathway alone, although the combination of CD40 and membrane Ig signaling leads to a strong enhancement of the IL-3 + GM-CSF-mediated IgM synthesis above that obtained with membrane Ig signaling alone. The demonstration that IL-3 and GM-CSF act directly as differentiation factors for B cells activated through their Ag receptor establishes a novel cytokine pathway for induction of humoral immunity.
T lymphocyte adhesion to human brain pericytes is mediated via very late antigen-4/vascular cell adhesion molecule-1 interactions.
Authors: Verbeek M M , Westphal J R , Ruiter D J , de Waal R M 
Published: December 2022

Abstract
T cell adhesion to the brain microvascular endothelium and subsequent migration into the brain parenchyma is one of the major events in the development of multiple sclerosis (MS). Interactions of the T cell integrin very late antigen-4 (VLA-4) with its receptor, vascular cell adhesion molecule-1 (VCAM-1) have been described to be of crucial importance for the development of MS. We investigated the expression of these adhesion molecules in MS brain tissue by immunohistochemical analysis, and studied their functional involvement in an in vitro T cell adhesion assay. A number of other adhesion molecules were studied for comparison. In cryosections of several MS brains, expression of VCAM-1 was demonstrated not only on the endothelium of vessels surrounding MS plaques, but also in perivascular positions, suggesting expression by pericytes. T cells adhered to both cell types in vitro. Both LFA-1/intercellular adhesion molecule-1 and VLA-4/VCAM-1 interactions were equally involved in the adhesion of T cells to TNF-alpha-stimulated endothelial cells. However, adhesion of T cells to TNF-alpha-stimulated pericytes was clearly dominated by VLA-4/VCAM-1 interactions. These results indicate that pericytes, next to endothelial cells, may play an important role in regulating T cell infiltration into the central nervous system.
Engineering a unique glycosylation site for site-specific conjugation of haptens to antibody fragments.
Authors: Leung S , Losman M J , Govindan S V , Griffiths G L , Goldenberg D M , Hansen H J 
Published: December 2022

Abstract
A natural N-linked glycosylation site (Asn-Val-Thr) at amino acid positions 18-20 (Kabat's numbering) was identified in the framework-1 (FR-1) region of the light chain variable (V kappa) domain of a murine anti-B cell lymphoma Ab, LL-2. Our earlier studies demonstrated that no contact between the V kappa-appended oligosaccharide and the Ag binding site was evident, because glycosylation at this site did not affect the Ag binding property of the Ab. By using the murine LL-2 F(ab')2 fragment (which is devoid of constant region-appended oligosaccharide) as substrate, as much as five bifunctional chelator molecules per F(ab')2 fragment could be site specifically conjugated at the V kappa-appended carbohydrate moiety with no reduction in immunoreactivity. The resulting conjugates labeled efficiently with both 90Y and 111In, with no significant effect on Ab affinity. In contrast, conjugation of less than five chelates/Ab fragment randomly at lysine residues resulted in a three- to fivefold reduction in affinity. By a single Arg to Asn mutation, an N-linked glycosylation site similar to that of LL-2 was introduced in the FR-1 segment of a nonglycosylated, humanized anti-carcinoembryonic Ag (CEA) Ab, MN-14 (hMN-14). Glycosylation at the engineered carbohydrate-addition site was demonstrated by SDS-PAGE analysis. Neither glycosylation nor site-specific conjugation of chelate at the V kappa-appended carbohydrate moiety resulted in the loss of immunoreactivity. The glycosylated hMN-14 conjugate labeled efficiently with 90Y.