bluuebunny/crossref_metadata_2025 huggingface dataset:
Transforming growth factor beta induces IgA production and acts additively with interleukin 5 for IgA production.
Authors: Sonoda E , Matsumoto R , Hitoshi Y , Ishii T , Sugimoto M , Araki S , Tominaga A , Yamaguchi N , Takatsu K
Published: June 2004

Effects of transforming growth factor beta (TGF-beta) on IgA production by LPS-stimulated B cells have been studied. TGF-beta itself could augment polyclonal IgA production in concomitant inhibition of polyclonal IgM and IgG1 production. Furthermore, TGF-beta and IL-5 additively augmented IgA production. TGF-beta exerted its activity early in the culture (by 2 d in a 5-d culture) and IL-5 was required late in the culture. Surface IgA- (sIgA-) B cells responded to TGF-beta for the development of IgA-secreting cells. By contrast, sIgA+ B cells, but not sIgA- B cells, responded to IL-5 for IgA production. These results suggest that TGF-beta has a differential role in the induction of IgA production from IL-5 on murine-activated B cells.
Analysis of restriction fragment length polymorphism in lymphokine genes of normal and autoimmune mice.
Authors: Richter G , Qin Z H , Diamantstein T , Blankenstein T
Published: June 2004

Analysis of RFLP has been employed in lymphokine genes of autoimmune and normal mice. No polymorphism could be detected in the loci containing IL-2, IL-2 receptor, IL-5, and IFN-gamma in NZB, NZW, BxSB, and MRL/lpr mice when compared with normal mice. Allelic forms were identified in the IL-1 alpha gene of BALB/c and in the IL-4 gene of NZW. The frequency of the Bam HI RFLP in the TNF-alpha gene of NZW which has been proposed to be associated with the development of autoimmune disease in (NZB x NZW)F1 mice has been analyzed in a number of different inbred strains and in wild mice. Since the same allele is inherited in most autoimmune, healthy laboratory and wild mice the TNF-alpha gene does not seem to be one of the causal agents that contributes to the development of autoimmunity in (NZB x NZW)F1 mice.
Activation of peripheral blood T cells via the p75 interleukin 2 receptor.
Authors: Yagita H , Nakata M , Azuma A , Nitta T , Takeshita T , Sugamura K , Okumura K
Published: June 2004

By using mAb and flow cytometry, a constitutive expression of the p75 IL-2R was revealed in human peripheral blood CD8+ T cells and TCR delta-1+ T cells as well as in CD16+ NK cells. Anti-p75 IL-2R mAb almost completely inhibited the induction of cytolytic activity in these T cells by brief exposure to IL-2, as estimated by anti-TCR/CD3 mAb-targeted cytotoxicity. While anti-p55 IL-2R mAb alone inhibited the response only modestly, maximal inhibition was achieved by combining both anti-p55 and anti-p75 IL-2R mAbs. These results indicate that the p75 IL-2R constitutively expressed on peripheral blood CD8+ T cells and TCR delta-1+ T cells is predominantly responsible for the direct activation of these cells by IL-2.
Purified perforin induces target cell lysis but not DNA fragmentation.
Authors: Duke R C , Persechini P M , Chang S , Liu C C , Cohen J J , Young J D
Published: June 2004

Rapid and extensive target cell DNA fragmentation is a unique characteristic of CTL-mediated killing. We studied the role of the granule pore-forming protein (PFP/perforin/cytolysin) of CTL in mediating lysis and DNA fragmentation of target cells. Perforin was isolated from murine CTL by sequential application of perforin-enriched granule fractions to four chromatographic columns: DEAE-Sepharose, Q-Sepharose, Polyanion SI, and Superose 12. Purified perforin was eluted as a single band of 70 kD in SDS-PAGE. While purified perforin produced potent lysis of a variety of target cells tested, it did not induce any measurable amount of DNA fragmentation. In parallel experiments, intact CTL produced marked DNA fragmentation of the same target cell populations. Our results suggest that perforin alone is not responsible for the DNA fragmentation observed during CTL-mediated killing and that other, as yet unknown, mediators or mechanisms are likely to be involved in the induction of target cell nuclear damage.
Cloning and sequencing of a cDNA expressing a recombinant house dust mite protein that binds human IgE and corresponds to an important low molecular weight allergen.
Authors: Tovey E R , Johnson M C , Roche A L , Cobon G S , Baldo B A
Published: June 2004

A cDNA clone coding for a mite allergen of mol wt approximately 14,000 has been isolated and its DNA sequence determined. The native component from mite extracts encoded by this DNA was identified by immunoprobing blots of mite body extract with human IgE eluted from the electroblotted cloned fusion polypeptides derived from the expressed cDNA clone. The clone encodes a polypeptide with a deduced mol wt of 17,460. The deduced amino acid sequence was not homologous to any known protein sequences and it contains no cysteine or tryptophan. On blots, 21 of 38 sera from mite-allergic subjects recognized the cloned material, and this recognition strongly correlated with IgE-binding to the native component on protein blots of mite extract.
Interleukin 4 induces selective production of interleukin 6 from normal human B lymphocytes.
Authors: Smeland E B , Blomhoff H K , Funderud S , Shalaby M R , Espevik T
Published: June 2004

In this paper we have shown that extensively purified human B lymphocytes respond to IL-4 treatment with a marked production of IL-6. Addition of anti-mu potentiated the effect of IL-4 on IL-6 production. Other cytokines tested like TNF-alpha and-beta, IFN-gamma, IL-1, IL-2, and IL-5 did not induce IL-6 secretion when given to resting B cells. Although B cells generally also produced TNF-alpha and TNF-beta upon stimulation, IL-4 did not induce TNF secretion and seemingly had a specific effect on IL-6 production.
Induction of human IgE synthesis by CD4+ T cell clones. Requirement for interleukin 4 and low molecular weight B cell growth factor.
Authors: DeKruyff R H , Turner T , Abrams J S , Palladino M A , Umetsu D T
Published: June 2004

We have analyzed in detail the precise requirements for the induction of human IgE synthesis using several experimental approaches with purified B cells and well-characterized alloantigen-specific CD4+ T cell clones expressing different profiles of lymphokine secretion. Using these clones under cognate conditions in which the B cells expressed alloantigens recognized by the cloned T cells, we have confirmed that IL-4 is required for the induction of IgE synthesis, but we have clearly demonstrated that IL-4 by itself is not sufficient. With several cloned CD4+ T cell lines, including an IL-4-producing clone that could not induce IgE synthesis, and cloned T cells pretreated with cyclosporin A to inhibit lymphokine synthesis, we showed that Th cell-B cell interactions are necessary for IgE synthesis, and that low molecular weight B cell growth factor (LMW-BCGF) and IL-4, in combination, are lymphokines of major importance in the induction of IgE synthesis. Together our results indicate that optimal induction of an IgE-specific response requires the exposure of B cells to a particular complex of signals that include (a) a signal(s) involving Th-B cell interaction that primes B cells to receive additional signals from soluble lymphokines, (b) a specific B cell proliferative signal provided by LMW-BCGF, and (c) a specific B cell differentiation signal provided by IL-4.
Regulation of interleukin 6 receptor expression in human monocytes and monocyte-derived macrophages. Comparison with the expression in human hepatocytes.
Authors: Bauer J , Bauer T M , Kalb T , Taga T , Lengyel G , Hirano T , Kishimoto T , Acs G , Mayer L , Gerok W
Published: June 2004

IL-6 is a cytokine with pleiotropic biological functions, including induction of the hepatic acute phase response and differentiation of activated B cells into Ig-secreting plasma cells. We found that human peripheral blood monocytes express the IL-6-R, which is undetectable on the large majority of lymphocytes of healthy individuals. Stimulation of monocytes by endotoxin or IL-1 causes a rapid downregulation of IL-6-R mRNA levels and a concomitant enhancement of IL-6 mRNA expression. IL-6 itself was found to suppress the IL-6-R at high concentrations. A gradual decrease of IL-6-R mRNA levels was observed along in vitro maturation of monocytes into macrophages. We show that downregulation of IL-6-R mRNA levels by IL-1 and IL-6 is monocyte specific, since IL-6-R expression is stimulated by both IL-1 and IL-6 in cultured human primary hepatocytes. Our data indicate that under noninflammatory conditions, monocytes may play a role in binding of trace amounts of circulating IL-6. Repression of monocytic IL-6-R and stimulation of hepatocytic IL-6-R synthesis may represent a shift of the IL-6 tissue targets under inflammatory conditions.
Expression of a public idiotype by human monoclonal IgM directed to myelin-associated glycoprotein and characterization of the variability subgroup of their heavy and light chains.
Authors: Brouet J C , Dellagi K , Gendron M C , Chevalier A , Schmitt C , Mihaesco E
Published: June 2004

Most studies using rabbit or mouse antisera failed to detect CRI between human IgM directed to MAG. We show here that 9 of 10 such IgM express a public CRI as defined by a nonhuman primate antiserum. Shared idiotype is likely involved in (or close to) the combining site of those IgM since antiidiotypic serum inhibited the binding of IgM to MAG and reacted with IgM having different variable regions of light and heavy chains. Partial aminoterminal sequence of heavy and light chains showed that anti-MAG IgM use either lambda chains (one IgM) or kappa light chains (six IgM) of different variability subgroups (V kappa IV in three instances, V kappa I in two, and V kappa II in one), whereas heavy chains belong to the VHIII (six IgM) or to the VHII (1 IgM) subgroup. These features distinguish these IgM from other human monoclonal IgM with a defined antibody activity, such as rheumatoid factors or cold agglutinins.
Regulation of MHC class II gene expression in macrophages by hematopoietic colony-stimulating factors (CSF). Induction by granulocyte/macrophage CSF and inhibition by CSF-1.
Authors: Willman C L , Stewart C C , Miller V , Yi T L , Tomasi T B
Published: June 2004

CSF-1 and granulocyte/monocyte CSF (GM-CSF) were shown to modulate the levels of Ia gene and protein expression in bone marrow-derived macrophages (BMM). Recombinant GM-CSF induced high levels of Ia expression, similar to the levels induced by INF-gamma, while IL-3 had no effect. In contrast, recombinant CSF-1 not only suppressed the basal levels of Ia gene and protein expression in BMM, but also inhibited the induction of Ia by IFN-gamma and GM-CSF. Basal levels of Ia were not inhibited by recombinant CSF-1 until after 16-24 h of culture, suggesting an indirect mechanism of suppression. IFN-alpha/beta and PGE2 were shown not to be involved in the CSF-1 inhibition of basal levels of Ia expression. However, the CSF-1-mediated suppression of both the basal levels of Ia expression and the induction of Ia in BMM by IFN-gamma and GM-CSF did correlate with the induction of cellular proliferation. These data imply that in addition to regulating hematopoiesis, CSFs may regulate the initiation of the immune response through their effects on Ia expression in macrophages.
Intraepithelial lymphocytes. Anatomical site, not T cell receptor form, dictates phenotype and function.
Authors: Goodman T , Lefrancois L
Published: June 2004

The function and structure of the TCR proteins of intraepithelial lymphocytes (IEL) were examined using a panel of mAbs specific for TCR-gamma/delta. Three subsets of TCR-gamma/delta+ IEL could be detected with five mAbs, termed GL1-GL5. The mAbs were able to trigger lysis via crosslinking of the IEL TCR and all of the subsets were constitutively cytolytic. Immunoprecipitation of IEL TCR proteins revealed that the GL2 mAb reacted only with gamma, delta heterodimers containing high Mr delta chains, while the other mAbs precipitated all of the observed gamma and delta proteins. Two-color fluorescence analysis showed that the GL2+ subset was contained within the larger GL1+ subset. The GL3 and GL4 mAbs appear to be specific for all TCR-gamma/delta while GL2 was V delta 4 specific. Analysis of IEL for TCR-alpha/beta expression demonstrated that approximately 20% of B6 IEL were TCR-alpha/beta+. Interestingly, this population of IEL contained Thy-1- and CT1+ cells, indicating that the unique phenotype of IEL was not restricted to TCR-gamma/delta+ cells. Moreover, the TCR-alpha/beta+ IEL were also constitutively cytolytic, suggesting that the intestinal milieu was controlling the functional programming of IEL regardless of TCR type. The mAbs reported here as well as the ability to exploit the distinct phenotype of IEL should prove useful in determining the function of IEL and the TCR-gamma/delta.
Myelopoietic enhancing effects of murine macrophage inflammatory proteins 1 and 2 on colony formation in vitro by murine and human bone marrow granulocyte/macrophage progenitor cells.
Authors: Broxmeyer H E , Sherry B , Lu L , Cooper S , Carow C , Wolpe S D , Cerami A
Published: June 2004

Two recently identified and purified murine macrophage inflammatory proteins MIP-1 and MIP-2 were tested in vitro both alone, and in combination with purified recombinant (r) murine (mu) GM-CSF, natural (n)muCSF-1, or rhuman (hu)G-CSF, for effects on mouse marrow CFU-GM, in combination with erythropoietin for effects on mouse marrow BFU-E, and in combination with rhuGM-CSF or rhuG-CSF for effects on human marrow CFU-GM. MIP-1 and MIP-2 did not stimulate, but did enhance by up to threefold, colony formation of mouse CFU-GM co-stimulated by rmuGM-CSF and nmuCSF-1, but not by rhuG-CSF, in the absence or presence of serum. MIP-1 and MIP-2 were maximally active at concentrations greater than or equal to 100 ng/ml and the actions appeared to be initiated during the DNA synthetic portion of the cell cycle. Neither MIP-1 nor MIP-2 at up to 1 microgram/ml had any effect on mouse BFU-E, in the absence or presence of erythropoietin. Both MIP-1 and MIP-2 had direct acting effects on purified mouse CFU-GM. The cloning efficiency of 200 purified cells plated with 50 U muCSF-1 was 82% with and 43% without MIP; the cloning efficiency with 50 U rmuGM-CSF was 65% with and 35% without MIP. MIP effects were not mimicked by bacterial LPS, rhuIL-1 alpha, rhuIL-6, or rmuIL-4, and were neutralized by their respective specific antibodies. MIP-1 and MIP-2 also enhanced endogenously stimulated and rhuGM-CSF-, but not rhuG-CSF-, stimulated colony formation by human marrow CFU-GM. These results demonstrate a new role for MIP-1 and MIP-2 in vitro as myelopoietic enhancing activities for CFU-GM.
Interferon gamma inhibits both proliferation and expression of differentiation-specific alpha-smooth muscle actin in arterial smooth muscle cells.
Authors: Hansson G K , Hellstrand M , Rymo L , Rubbia L , Gabbiani G
Published: June 2004

Differentiation of muscle cells is characterized morphologically by the acquisition of contractile filaments and characteristic shape changes, and on the molecular level by induction of the expression of several genes, including those for the muscle-specific alpha-actin isoforms. IFN-gamma is an inhibitor of proliferation for several cells, including vascular smooth muscle, and is also an inducer of differentiated properties for several hematopoietic cells. We have therefore investigated whether IFN-gamma affects the expression of alpha-smooth muscle actin in cultured arterial smooth muscle cells. Cells exposed to IFN-gamma show a reduction of alpha-smooth muscle actin-containing stress fibers, as detected by immunofluorescence. The effect was observed in all phases of the cell cycle, and was caused by a reduction of the synthesis of alpha-smooth muscle actin protein as revealed by two-dimensional electrophoretic analysis of actin isoforms. RNA hybridization using a cRNA probe that hybridizes to all actin mRNAs showed that IFN-gamma-treated cells have a reduced content of the 1.7-kb mRNA that codes for alpha-smooth muscle actin, and to a lesser extent, also of the 2.1-kb mRNA encoding the beta and gamma-cytoplasmic actins. The reduction of alpha-smooth muscle actin mRNA was confirmed using an alpha-smooth muscle actin-specific cRNA probe. The reduction of alpha-smooth muscle actin mRNA occurs within 12 h, and is dependent on protein synthesis, since cycloheximide treatment reversed the effect. The inhibition of this mRNA species was dose dependent, and detectable by RNA hybridization at a dose of 50 U/ml IFN-gamma. These results suggest that the differentiation of arterial smooth muscle cells is not necessarily coupled to an inhibition of cellular proliferation. Instead, IFN-gamma may regulate the expression of several genes that control both proliferation and expression of differentiation markers.
Antibodies to cachectin/tumor necrosis factor reduce interleukin 1 beta and interleukin 6 appearance during lethal bacteremia.
Authors: Fong Y , Tracey K J , Moldawer L L , Hesse D G , Manogue K B , Kenney J S , Lee A T , Kuo G C , Allison A C , Lowry S F
Published: June 2004

Cytokines secreted in response to invading micro-organisms are important mediators of detrimental hemodynamic and metabolic changes in the host. To test whether cachectin/TNF plays a role in triggering release of other cytokines in the setting of infection, anesthetized baboons were passively immunized against systemic cachectin/TNF before infusion of a LD100 dose of live Escherichia coli. Bacteremia led to significant increases in circulating levels of cachectin/TNF, IL-1 beta, and IL-6. Although bacterial endotoxin/lipopolysaccharide is a potent stimulus for the synthesis and release of IL-1 and IL-6 in vitro, specific neutralization of cachectin/TNF in vivo with mAb pretreatment significantly attenuated both the IL-1 beta and the IL-6 responses despite fulminant overwhelming bacteremia. These data suggest that cachectin/TNF is essential for the initiation or amplification of IL-1 and IL-6 release during lethal gram-negative septic shock syndrome.
Interleukin 6 decreases cell-cell association and increases motility of ductal breast carcinoma cells.
Authors: Tamm I , Cardinale I , Krueger J , Murphy J S , May L T , Sehgal P B
Published: June 2004

Treatment of transformed breast duct epithelial cells with IL-6 produces a unique cellular phenotype characterized by diminished proliferation and increased motility. Human ductal carcinoma cells (T-47D and ZR-75-1 lines) are typically epithelioid in shape and form compact colonies in culture. Time-lapse cinemicrography shows that some untreated cells can transiently become fusiform or stellate in shape and separate from each other within a colony, but they usually rejoin their neighbors. While IL-6 suppresses the proliferation of these carcinoma cells, the IL-6-treated cells generally become stellate or fusiform and show increased motility. These changes persist as long as the cells are exposed to IL-6. This results in the dispersal of cells within colonies. The effects on cell growth, shape, and motility are reversible upon removal of IL-6. IL-6-treated T-47D cells display diminished adherens-type cell junctions, as indicated by markedly decreased vinculin-containing adhesions and intercellular desmosomal attachments. The effects on ZR-75-1 cell shape, colony number, and DNA synthesis are dependent on IL-6 concentration in the range from 0.15 to 15 ng/ml. Higher concentrations are required in T-47D cells for equivalent effects. Anti-IL-6 immune serum blocks IL-6 action. IL-6 represents a well-characterized molecule that regulates both the proliferation and junction-forming ability of breast ductal carcinoma cells.
Engagement of CD4 and CD8 expressed on immature thymocytes induces activation of intracellular tyrosine phosphorylation pathways.
Authors: Veillette A , Zúñiga-Pflücker J C , Bolen J B , Kruisbeek A M
Published: June 2004

Accumulating data suggest that the target cells for selection events leading to establishment of the mature T cell repertoire are the functionally immature double-positive (CD4+/CD8+) thymocytes, and that the CD4 and CD8 antigens expressed on these cells play important roles in these processes. In an attempt to define the biochemical pathways implicated in these events, we have studied the effects of engagement of accessory molecules on tyrosine protein phosphorylation. The results of our experiments demonstrate that engagement of CD4 and CD8 expressed on double-positive thymocytes is coupled with a rapid tyrosine protein phosphorylation signal. Further analyses have revealed that these two surface molecules are physically associated with the internal membrane tyrosine protein kinase p56lck in immature thymocytes, and that the catalytic function of lck expressed in double-positive thymocytes is significantly enhanced upon engagement of CD4. These data provide evidence that tyrosine-specific protein phosphorylation pathways coupled to the CD4 and CD8 T cell surface antigens are functional in immature thymocytes, and therefore, formally prove that signaling functions of CD4 and CD8 molecules are operative in immature thymocytes.
Human immunodeficiency virus 1. Predominance of a group-specific neutralizing epitope that persists despite genetic variation.
Authors: Berkower I , Smith G E , Giri C , Murphy D
Published: June 2004

HIV-1 is known to show a high degree of genetic diversity, which may have major implications for disease pathogenesis and prevention. If every divergent isolate represented a distinct serotype, then effective vaccination might be impossible. However, using a sensitive new plaque-forming assay for HIV-1, we have found that most infected patients make neutralizing antibodies, predominantly to a group-specific epitope shared among three highly divergent isolates. This epitope persists among divergent isolates and rarely mutates, despite the rapid overall mutation rate of HIV-1, suggesting that it may participate in an essential viral function. These findings, plus the rarity of reinfections among these patients, suggest that HIV-1 may be more susceptible to a vaccine strategy based on a group-specific neutralizing epitope than was previously suspected.
The specific interaction of helper T cells and antigen-presenting B cells. IV. Membrane and cytoskeletal reorganizations in the bound T cell as a function of antigen dose.
Authors: Kupfer A , Singer S J
Published: June 2004

We have used double-immunofluorescence labeling to determine the surface distributions of LFA-1 and CD4, and the intracellular distributions of the cytoskeletal protein talin and of the microtubule organizing center (MTOC) of cloned Th cells in 1:1 cell couples with antigen (Ag)-specific APC of the B cell type (B-APC). The Th cell was directed to a peptide fragment of the Ag OVA in the context of IAd. The B-APC was the transfected A20 B hybridoma cell A20-HL, bearing on its surface a surface Ig specific for the hapten TNP, and pulsed with different concentrations of DNP-OVA. At sufficiently high doses of DNP-OVA (greater than 100 ng/ml), in essentially all couples, LFA-1, CD4, and talin were each concentrated at the Th cell membrane where it was in contact with the B-APC, and the MTOC inside the Th cell was reoriented to face the contact region. At lower doses of DNP-OVA (between 50 and 10 ng/ml), in all couples, LFA-1 and talin were concentrated at the Th/B-APC contact region, but the extent of CD4 clustering, MTOC reorientation, and Th cell proliferation all decreased with decreasing Ag dose. With no Ag, none of these effects was observed. These and other data indicate that two distinct signals are received by the Th cell that is specifically bound to its B-APC. The first signal, at low Ag doses, stimulates a linkage of LFA-1 and talin in the Th cell, and a specific LFA-1-mediated intercellular adhesion; the second signal, at higher Ag doses, is required to induce Th cell proliferation, with which the Th-MTOC reorientation and CD4 clustering are correlated.
Ras oncogene mutation in multiple myeloma.
Authors: Neri A , Murphy J P , Cro L , Ferrero D , Tarella C , Baldini L , Dalla-Favera R
Published: June 2004

The frequency of ras (H-, K-, and N-ras) and c-myc oncogenes was investigated in multiple myeloma (MM). By means of the polymerase chain reaction (PCR)/oligonucleotide hybridization method, DNA from 56 tumor biopsies was analyzed for the presence of activating mutations involving codons 12 and 61 of the H-, K-, and N-ras genes and codon 13 of the N-ras gene. Mutations, involving the N- or K-ras genes, were detected in 18 of 56 (32%) cases of which 12/43 (27%) were at diagnosis and 6/13 (46%) were after treatment. In some cases, multiple mutations affecting different ras alleles were detected. Direct nucleotide sequence analysis of PCR products indicated that a more heterogeneous nature of the base pair changes than previously shown for other tumors along with a preferential involvement of N-ras codon 61. The heterogeneity of MM cases with respect to the presence of ras oncogenes prompted an analysis of possible correlations with different clinico-pathologic characteristics of MM from which a correlation between the presence of ras oncogenes and a partial or complete lack of response to therapy emerged. The frequency of activating rearrangements or mutations of the c-myc gene were studied by Southern blot analysis and PCR sequencing, respectively. However, contrary to previous reports involving mostly MM cell lines, no structural alterations of the c-myc gene were found. These results indicate that ras, but not c-myc, oncogenes are activated in vivo in MM cells, representing the first oncogene alteration that has been associated at appreciable frequency with this type of malignancy. While the mechanism of occurrence and biological role of ras activation in MM remains to be elucidated, the preliminary correlations observed in this study between the presence of ras oncogenes and poor therapeutic response suggest that further investigations of the possible prognostic significance of these alterations are necessary.
Identification of a functional NF-kappa B binding site in the murine T cell receptor beta 2 locus.
Authors: Jamieson C , Mauxion F , Sen R
Published: June 2004

We have identified a sequence in the TCR beta 2 locus that is homologous to the kappa B site in the Ig kappa light chain enhancer. This element, TCR beta-B, is located in the vicinity of previously identified T cell-specific DNase1 hypersensitive sites. Transfection analysis shows that a 60-bp fragment encompassing this site is preferentially active in T cells stimulated with phorbol esters or the HTLV-1 tax gene product compared with a B cell line that constitutively expresses NF-kappa B. Our results provide the first evidence for transcriptional regulatory sequences residing within the J beta 2-C beta 2 intron and suggest the possible involvement of these sequences in modulation of TCR beta gene expression upon cellular activation.
Effects of the neutrophil-activating peptide NAP-2, platelet basic protein, connective tissue-activating peptide III and platelet factor 4 on human neutrophils.
Authors: Walz A , Dewald B , von Tscharner V , Baggiolini M
Published: June 2004

Platelet basic protein (PBP), connective tissue-activating peptide III (CTAP-III), and platelet factor 4 (PF-4) were purified from human platelet release supernatants by heparin-Sepharose ion-exchange and reversed-phase HPLC, and their neutrophil-activating effects were compared with those of NAP-2, a peptide of 70 amino acids corresponding to part of the sequence of PBP (1) and with sequence homology to NAF/NAP-1. NAP-2-induced elastase release and a rise in cytosolic free Ca2+ at concentrations between 0.3 and 100 nM, and neutrophil chemotaxis at concentrations between 0.03 and 10 nM. It was half as potent as NAF/NAP-1 in inducing exocytosis but showed the same activity in the other responses. By contrast, only minimal if any effects were obtained with PBP, CTAP-III, and PF-4 up to 100 nM. NAP-2 thus appears to behave like a typical chemotactic receptor agonist. It could be generated from PBP and/or CTAP-III released from activated platelets and lead to the accumulation of neutrophils in platelet aggregates.
Recombinant interleukin 4 suppresses the production of interferon gamma by human mononuclear cells.
Authors: Peleman R , Wu J , Fargeas C , Delespesse G
Published: June 2004

rIL-4 inhibits the production of IFN-gamma by PBMC stimulated with mitogens or allogeneic cells. The suppression is observed at the protein and at the mRNA level; it is dose and time dependent, and it is abolished by a neutralizing mAb to IL-4. It is suggested that the balance between the production of IL-4 and IFN-gamma may be significantly influenced by the chronological order of activation of their respective gene.
Involvement of CD56 (NKH-1/Leu-19 antigen) as an adhesion molecule in natural killer-target cell interaction.
Authors: Nitta T , Yagita H , Sato K , Okumura K
Published: June 2004

The CD56 differentiation antigen, recognized by anti-Leu-19 and NKH-1 mAbs, is a 200-220-kD glycoprotein that is expressed predominantly on human NK cells and a minor subset of T lymphocytes mediating MHC-unrestricted cytotoxicity. The recent finding that CD56 is an isoform of the neural cell adhesion molecule (N-CAM) prompted us to examine the adhesive function of CD56 in the NK-target cell interaction. Synergistic inhibitory effects of anti-CD56 mAbs with anti-LFA-1 and/or anti-LFA-3 mAbs were demonstrated on NK cell-mediated cytotoxicity and on NK cell binding to target cells only when the target cells also express CD56. These findings indicate that CD56 on NK cells can serve as the third pathway of cell adhesion other than those mediated by the CD2/LFA-3 and LFA-1/ICAM-1 interactions, and is involved in NK cell cytotoxicity when interacting with the cells bearing N-CAM.
Activation primes human B lymphocytes to respond to heat shock.
Authors: Spector N L , Freedman A S , Freeman G , Segil J , Whitman J F , Welch W J , Nadler L M
Published: June 2004

Crosslinkage of the B cell antigen receptor by anti-mu beads or SAC results in the selective induction of hsp70. We have observed that activated cells, having enhanced expression of hsp70, survive lethal stimuli much better than their unactivated counterparts. These results are in accordance with the proposal that hsp70 is essential for cells to survive lethal environmental stresses. Moreover, the activation event itself primes B cells thereby enabling them to increase the expression of both hsp70 mRNA and protein. This is the first demonstration that triggering of B cells via crosslinkage of sIg is accompanied by the induction of thermotolerance without the need for a prior sublethal heat treatment.
IgE synthesis by chronic lymphocytic leukemia cells.
Authors: Sarfati M , Luo H , Delespesse G
Published: June 2004

The present results indicate that B cells isolated from chronic lymphocytic leukemia (B-CLL) from 11 of 14 patients are capable of specifically producing IgE upon costimulation with IL-4 and hydrocortisone (HC). IgE is detected by intracytoplasmic fluorescence staining and by RIA. Clinical, hematological, and immunological parameters (including Rai stage, WBC, Lc, sIg kappa/lambda, CD5, and CD23 expression) cannot distinguish the IgE responder from the nonresponder patients. IL-4 alone is a potent inducer of human IgE synthesis by normal PBMC and we show here that its effect is strikingly enhanced by HC. The IgE produced by B-CLLs are monoclonal since they display the same L chain type as the freshly isolated CD5+ B-CLLs. We, therefore, conclude that the combination of IL-4 and HC can abrogate the maturation arrest of CD5+ B-CLLs by inducing their differentiation into IgE-producing cells. The present data provide a unique model to study the isotype switching to IgE and the regulation of human IgE synthesis by monoclonal human B cells.
Stimulation of rat hepatocyte fibronectin production by monocyte-conditioned medium is due to interleukin 6.
Authors: Lanser M E , Brown G E
Published: June 2004

In this report, conditioned media from LPS-stimulated monocytes increased rat hepatocyte production of fibronectin (Fn) in a dose-dependent manner. Preincubation of the conditioned media with anti-IL-6, but not with anti-IL-1 alpha, anti-IL-1 beta, or anti-TNF, completely neutralized the Fn-stimulating activity. 10-100 pg/ml of rIL-6 was sufficient to increase Fn production. Neither IL-1 nor TNF had an effect on Fn production. The Fn-stimulating activity of IL-6 could be specifically neutralized only with anti-IL-6, but not with anti-IL-1 or anti-TNF. The increased Fn produced was shown to be of the plasma rather than the cellular form. These results demonstrate that IL-6 is the factor in monocyte-conditioned media that stimulates Fn production, and that IL-6 is the monokine tested with such activity.
A peptide binding protein having a role in antigen presentation is a member of the HSP70 heat shock family.
Authors: Vanbuskirk A , Crump B L , Margoliash E , Pierce S K
Published: June 2004

The T cell recognition of globular protein antigens requires the processing and presentation of the antigen by Ia-expressing APCs. Processing is believed to involve the uptake of antigen into an acidic compartment where proteolysis occurs. The resulting peptides containing the T cell antigenic determinant are associated with Ia and presented at the cell surface to the specific T cells. The mechanisms by which antigenic peptides become associated with Ia is not known. We previously described a peptide binding protein of 72/74 x 10(3) Mr (PBP72/74) that plays a role in antigen presentation as shown by the ability of an antiserum raised in rabbits to affinity-purified PBP72/74 to block presentation of cytochrome c to a cytochrome c-specific T cell hybrid. Here we show that PBP72/74 is recognized by mAbs specific for members of the HSP70 family of proteins. In Western blots PBP72/74 is bound by mAb 7.10, specific for an evolutionarily conserved epitope of HSP proteins and by mAb N27, specific for both the constitutively expressed and inducible 72/73 x 10(3) Mr HSP70 proteins. In addition, PBP72/74 shares a second common feature of the HSP proteins, that of binding to ATP. Indeed, ATP causes the release of PBP72/74 from binding to a peptide fragment of cytochrome c (Pc 81-104) and PBP72/74 can be eluted from ATP columns by Pc 81-104. Finally, a portion of PBP72/74 is shown to be present on B cell surfaces by immunofluorescence staining. Thus, it appears that characteristics of the heat shock proteins are shared by a protein playing a role in antigen presentation, suggesting some commonality in function.
Comparison of exon 5 sequences from 35 class I genes of the BALB/c mouse.
Authors: Brorson K A , Hunt S W , Hunkapiller T , Sun Y H , Cheroutre H , Nickerson D A , Hood L
Published: June 2004

DNA sequences of the fifth exon, which encodes the transmembrane domain, were determined for the BALB/c mouse class I MHC genes and used to study the relationships between them. Based on nucleotide sequence similarity, the exon 5 sequences can be divided into seven groups. Although most members within each group are at least 80% similar to each other, comparison between groups reveals that the groups share little similarity. However, in spite of the extensive variation of the fifth exon sequences, analysis of their predicted amino acid translations reveals that only four class I gene fifth exons have frameshifts or stop codons that terminate their translation and prevent them from encoding a domain that is both hydrophobic and long enough to span a lipid bilayer. Exactly 27 of the remaining fifth exons could encode a domain that is similar to those of the transplantation antigens in that it consists of a proline-rich connecting peptide, a transmembrane segment, and a cytoplasmic portion with membrane-anchoring basic residues. The conservation of this motif in the majority of the fifth exon translations in spite of extensive variation suggests that selective pressure exists for these exons to maintain their ability to encode a functional transmembrane domain, raising the possibility that many of the nonclassical class I genes encode functionally important products.
Tolerance-related V beta clonal deletions in normal CD4-8-, TCR-alpha/beta + and abnormal lpr and gld cell populations.
Authors: Singer P A , Balderas R S , McEvilly R J , Bobardt M , Theofilopoulos A N
Published: June 2004

We have analyzed tolerance-related clonal deletion of Mls-and I-E-reactive thymocytes at the RNA level using a multi-V beta probe RNAse protection assay, and used this phenomenon to identify the maturation stage of the abnormally expanded CD4-8-, TCR-alpha/beta + subset in lpr and gld homozygous mice, and of the phenotypically similar minor thymocyte subset found in normal mice. Essentially complete V beta clonal deletions were detected in lpr and gld cells of all appropriate background strains. Substantial, but not complete, V beta clonal deletions were also detected in the CD4-8- TCR-alpha/beta + subset of normal mice. Since expression of CD4/CD8 is required for V beta clonal deletions to occur, we conclude that lpr and gld cells, and at least a portion of CD4-8- TCR-alpha/beta + thymocytes in normal mice, are derived by secondary loss of CD4/CD8 accessory molecules from more mature CD4+8+ precursors. One possible interpretation of these findings is that such CD4/CD8 loss may affect a class of self-reactive thymocytes that have escaped direct clonal deletion. Exportation and expansion of such cells in the periphery may be an important contributory factor in the induction of systemic autoimmunity.
Equivalence of human and mouse CD4 in enhancing antigen responses by a mouse class II-restricted T cell hybridoma.
Authors: von Hoegen P , Miceli M C , Tourvieille B , Schilham M , Parnes J R
Published: June 2004

We have examined the ability of hCD4 to interact functionally with mouse class II MHC molecules using the mouse T cell hybridoma BI-141, specific for beef insulin. We have previously shown that expression of mouse CD4 results in a marked enhancement of IL-2 release by BI-141 cells in response to beef insulin or, in a cross-reactive response, to pork insulin, on the appropriate mouse APCs. We now demonstrate that expression of hCD4 results in an equivalent stimulation of antigen responses by this mouse T cell hybridoma. The specificity of this effect was demonstrated by mAb and gp120 blocking studies. These data provide the first direct evidence for function of hCD4 and in an exclusively mouse system.
Reactivity of V beta 17a+ CD8+ T cell hybrids. Analysis using a new CD8+ T cell fusion partner.
Authors: Burgert H G , White J , Weltzien H U , Marrack P , Kappler J W
Published: June 2004

Tolerance to IE molecules leads to deletion of V beta 17a-bearing T cells. Both, the CD4+ as well as the CD8+ T cell subsets are affected. A large percentage of CD4+ V beta 17a+ T cell hybrids recognize IE molecules. We now have investigated the reactivity for IE antigens of CD8+ V beta 17a+ T cell hybrids. Using a transfection approach, we have introduced the murine CD8 molecule into different V beta 17a+ T cell hybrids. Furthermore, the CD8 cDNA was transfected into the BW5147 alpha-beta- fusion partner. This allowed us to generate a large number of V beta 17a+ T cell hybrids by fusion with the appropriate T cells. Only 6% of T cell hybrids were stimulated to produce IL-2 upon incubation with IE+ cells. However, in those, the CD8 molecule seemed not to contribute to the IE reactivity of the hybrid, since mAbs against the CD8 molecule failed to inhibit their reactivity. This low percentage of V beta 17a+ CD8+ IE-reactive T cell hybrids contrasts with the strong reduction of CD8+ V beta 17a+ T cells in IE+ mice, strongly suggesting that elimination of such cells in the thymus occurs when they are coexpressing CD4 and CD8. This view was confirmed by the occasional expression of CD4 in some hybrids in which case IE reactivity was detected. Furthermore, we demonstrated the functional integrity of the introduced CD8 molecule by: (a) reconstitution of the IL-2 response in a class I-restricted TNP-specific T cell hybrid; and (b) by generation of alloreactive class I-restricted T cell hybrids using the new CD8+ fusion cell line. This CD8+ fusion partner, BWLyt2-4, should prove useful to study antigen processing and antigen presentation requirements of class I-restricted T cells.
Generation of biliary lesions after transfer of human lymphocytes into severe combined immunodeficient (SCID) mice.
Authors: Krams S M , Dorshkind K , Gershwin M E
Published: June 2004

Human PBL have been reported to reconstitute B and T cells as well as human serum Ig in mice with severe combined immunodeficiency disease (SCID). To confirm these observations and attempt the transfer of an autoimmune disease to the immunodeficient animals, groups of SCID mice received an injection of PBL from patients with primary biliary cirrhosis (PBC) or from normal volunteers. By 8 wk after the injection of 10-42 x 10(6) PBL into the mice, human lymphoid cells were detected in the spleen of approximately half of the animals and all had detectable serum levels of human IgG. Moreover, the sera of SCID mice that received cells from patients with PBC contained human antimitochondrial antibodies (AMA) to dihydrolipoamide acetyltransferase, the major mitochondrial autoantigen of PBC. Histologically, a human mononuclear cell infiltrate was present around the portal areas of the liver and inflammation, bile duct atypica, and necrosis of bile duct cells were observed. While the biliary lesions in the SCID recipients of PBC cells were more severe, a mononuclear infiltrate was clearly evident in mice that received cells from normal donors, suggesting the presence of a graft-vs.-host-like disease. While these data are the first to describe an animal model with both the humoral and cellular characteristics of PBC, they also raise an interesting question regarding the preferential localization of lymphoid cells to the biliary system.
Mapping of the Epstein-Barr virus and C3dg binding sites to a common domain on complement receptor type 2.
Authors: Lowell C A , Klickstein L B , Carter R H , Mitchell J A , Fearon D T , Ahearn J M
Published: June 2004

Complement receptor type 2 (CR2;CD21), a member of the superfamily of proteins containing short consensus repeats (SCRs), is the B cell receptor for both the gp350/220 envelope protein of Epstein-Barr virus (EBV), and for the C3dg protein of complement. By analysis of CR2 deletion mutants and chimeras formed with CR1 (CD35) we determined that of the 15 SCRs in CR2, the NH2-terminal two SCRs are necessary and sufficient to bind both gp350/220 and C3dg with affinities equivalent to those of the wild-type receptor. The epitope for OKB-7, a mAb that blocks binding of both EBV and C3dg and shares with these ligands B cell-activating capabilities, also requires both SCR-1 and SCR-2, whereas mAbs lacking these functions bind to other SCRs. Thus, EBV, a polyclonal activator of B cells, has selected a site that is proximate or identical to the natural ligand binding site in CR2, perhaps reflecting the relative immutability of that site as well as its signal transducing function.
Capacity of unprimed CD4+ and CD8+ T cells expressing V beta 11 receptors to respond to I-E alloantigens in vivo.
Authors: Gao E K , Kanagawa O , Sprent J
Published: June 2004

Self tolerance induction in the thymus is known to delete T cells expressing certain V beta TCR molecules. In particular, V beta 17a+ and V beta 11+ T cells are selectively deleted in mice expressing H-2 I-E molecules. Although this finding implies that V beta 17a+ and V beta 11+ T cells have specificity for self I-E molecules, studies with V beta 11+ hybridomas prepared from mature lymphocytes taken from I-E- mice have shown that the vast majority of these hybridomas do not display I-E alloreactivity, at least in vitro. To examine whether V beta 11+ T cells are capable of reacting to I-E antigens in vivo, normal unprimed T cells from I-E- B10.A(4R) mice were transferred to irradiated I-E+ B10.A(2R) hosts and harvested from thoracic duct lymph of the recipients at various intervals. The donor T cells recovered in early lymph collections showed no reactivity to the I-E antigens of the host in vitro, presumably as a reflection of selective sequestration of the host-reactive cells in the lymphoid organs. Significantly, the disappearance of functional host-reactive cells from TDL was paralleled by a 90-95% reduction of V beta 11+ CD4+ cells. Blast cells were rare in early lymph collections but accounted for nearly all of the lymph-borne cells by day 3 after transfer. These blast cell populations contained a surprisingly high proportion of V beta 11+ cells, i.e., up to 25% in some experiments. Interestingly, the enrichment for V beta 11+ cells in the blast populations applied to CD8+ cells as well as to CD4+ cells. Collectively, the data suggest that in marked contrast to the failure of V beta 11+ cells to respond to I-E antigens in vitro, a high proportion of normal resting V beta 11+ cells are capable of reacting to I-E alloantigens in vivo.
The Mac-2 antigen is a galactose-specific lectin that binds IgE.
Authors: Cherayil B J , Weiner S J , Pillai S
Published: June 2004

A cDNA encoding the Mac-2 antigen, a surface marker highly expressed by thioglycollate-elicited macrophages, has been cloned by immunoscreening of a lambda gt11-P388D1 expression library. The nucleotide sequence of the cDNA is identical to that of carbohydrate-binding protein 35, a galactose-specific lectin found in fibroblasts and highly homologous to a rat IgE-binding protein from basophilic leukemia cells. The in vitro synthesized Mac-2 protein displayed the expected carbohydrate- and IgE-binding properties. By pulse-chase analysis and subcellular fractionation studies, the Mac-2 protein was found in the cytosol but was also seen to accumulate in the extracellular medium. The latter finding was surprising in view of the fact that the cDNA did not encode a signal peptide or transmembrane domain. An alternatively spliced cDNA with the potential to encode a NH2 terminally extended Mac-2 protein with a stretch of hydrophobic amino acids at its NH2 terminus was also found, but it is not clear whether it is the source of the extracellular Mac-2. Possible functions for the Mac-2 protein based on its lectin- and IgE-binding properties are discussed.
One synchronous wave of B cell development in mouse fetal liver changes at day 16 of gestation from dependence to independence of a stromal cell environment.
Authors: Strasser A , Rolink A , Melchers F
Published: June 2004

Precursor cells of the B lineage can be enriched from mouse fetal liver by FACS with the aid of the pre-B cell-specific mAb G-5-2. The cells are concomitantly enriched for cells expressing the pre-B cell-specific gene lambda 5, and for cells developing to LPS-reactive mature B cells. The enriched purified precursors are not influenced by rIL-2 through -7, alone or in combination, to develop to mitogen-reactive, sIg+ cells. Marginal proliferation of the precursors is observed in response to IL-3 plus -4, and IL-6 plus -7, and this does not change in the presence of stromal cells. Development to mitogen-reactive, sIg+ cells is dependent on interactions with embryonic stromal cells from fetal liver. Two mAbs raised against the stromal cells inhibit this development. Two phases of precursor cell development can be distinguished in fetal liver. Between days 13 and 15 of gestation, it is dependent on stromal cell interactions, thereafter, from days 16 to 19, it is independent. A sudden increase in the number of mitogen-reactive, sIg+ B lineage cells occurs within 24 h between days 16 and 17. All these results indicate that B cell development occurs in one wave with synchronous steps of changes from a mitogen-insensitive, sIg-, stromal cell dependent to a mitogen-reactive, sIg+, stromal cell-independent B lineage line.