bluuebunny/crossref_metadata_2025_split huggingface dataset:
Immunoregulatory role of CD40 in human B cell differentiation.
Authors: Splawski J B , Fu S M , Lipsky P E 
Published: December 2022

Abstract
CD40 is a member of a family of surface molecules with homology to the nerve growth factor receptor and is expressed on B cells. The role of CD40 in regulating human B cell differentiation and the production of specific Ig isotypes was examined. In the absence of other stimuli, anti-CD40 and IL-4 induced the secretion of IgM, IgG, and IgE by purified human peripheral blood B cells. However, addition of formalinized Staphylococcus aureus (SA) enhanced the response. In the presence of SA, anti-CD40 and IL-4 induced the secretion of IgM, IgG1, IgG2, IgG3, and IgG4 in addition to IgE. No consistent effect on IgA secretion was demonstrated. The combination of SA, anti-CD40, and IL-4 induced one tenth of the total Ig production that was stimulated by SA and IL-2, with a different distribution of Ig H chain isotypes. B cells stimulated with SA, anti-CD40, and IL-4 secreted a greater percentage of IgG4 and IgE and a decreased percentage of IgG1 and IgA, compared with that secreted in response to SA and IL-2. Anti-CD40 did not induce Ig production in combination with IL-2 and did not alter the Ig secreted in response to SA and IL-2. Stimulation with SA, anti-CD40, and IL-4 caused Ig H chain isotype switch, inasmuch as IgG and IgE secretion could be induced from preimmune cord blood B cells and IgD+ naive adult B cells and IgE secretion could be induced from IgE- adult B cells. Ig secretion by purified B cells stimulated with SA, IL-4, and anti-CD40, but not with SA and IL-2, was significantly enhanced by anti-CD18 or anti-ICAM-1 mAb, suggesting that homotypic aggregation induced by anti-CD40 might limit Ig production. Finally, anti-CD40 was found to inhibit Ig production by B cells cultured with anti-CD3-activated T cells. These results suggest that engagement of the CD40 molecule on B cells provides signals that permit IL-4 to induce Ig isotype switching. This response is limited by LFA-1-mediated homotypic interactions of B cells. Engagement of CD40 by the ligand expressed by activated T cells appears to be important for the activation of B cells during T cell-B cell collaboration and the production of all isotypes of Ig.
Purified beta-chain of MHC class II binds to CD4 molecules on transfected HeLa cells.
Authors: Nag B , Wada H G , Passmore D , Clark B R , Sharma S D , McConnell H M 
Published: December 2022

Abstract
The initial event triggering the activation of Th cells occurs when the TCR interacts with antigenic peptide in the context of the MHC II on APC. Various T cell accessory molecules including CD4, CD28, and LFA-1 participate and facilitate the activation event. Although some evidence for the interaction of MHC II and CD4 is available, the site of MHC class II (alpha-chain, beta-chain, or both chains) for CD4 interaction has not yet been clearly defined. Results from different laboratories had indicated the involvement of alpha 1, beta 1, and beta 2 domains of MHC class II molecules in CD4 interaction. Recently, a conserved site of DR beta 2 domain has been identified that involves CD4 interaction that is analogous to MHC class I binding site for CD8 molecule. In this report, direct binding of affinity-purified HLA-DR2 dimer and its isolated alpha- and beta-chains to CD4 was studied using a CD4-transfected HeLa cell line. Preferential binding of the beta-chain and intact MHC II dimer to the CD4-transfected cells was observed and found to be specifically inhibited by anti-CD4 mAb. In contrast, the isolated alpha-chain of HLA DR2 did not show significant binding to CD4-transfected cells. Complexes of radiolabeled DR2 dimer or beta-chain alone with an immunodominant epitope from myelin basic protein (83-102) did not show any further increase in binding of these molecules. Binding of the beta-chain to CD4+ cells was markedly inhibited by a DR beta 1 peptide (35-46) and was partially inhibited by a DR beta 2 peptide (134-148) of MHC class II molecule. These results suggest the involvement of at least two conserved regions of the beta polypeptide chain of MHC class II in CD4 interaction. Because in our experiments transfected cells lack TCR molecules and the binding of DR2 to the CD4-transfected cells was unaffected by added antigenic peptide, it is possible that the interaction of MHC class II to CD4 is independent of TCR occupancy.
V region diversity in human anti-insulin antibodies. Preferential use of a VHIII gene subset.
Authors: Thomas J W 
Published: December 2022

Abstract
Data on structures used by human antibody repertoires are derived principally from lymphoid malignancies and from autoantibodies that often express VH genes from the developmentally regulated fetal repertoire. To determine whether human immune responses generated by exogenous Ag use a pool of VH genes distinct from the fetal repertoire, nucleotide and predicted amino acid sequences were determined for five anti-insulin B cell clones from a type I diabetic patient treated with human insulin. The data show that a set of VHIII genes is preferentially used by human anti-insulin B cells. Structural features indicate that these expressed VH are derived from germ-line genes that are not frequent in fetal repertoires and these genes have undergone Ag-driven somatic mutation. The preferential use of related VH segments contrasts with the BALB/c anti-insulin response, which uses multiple V genes elements largely unmutated from germ-line sequences. In addition, long CDRH3 structures in human anti-insulin mAb are generated by complex gene interaction mechanisms that are not seen in murine anti-insulin mAb. Interestingly, similar potential insulin-binding structures are used by antibodies from both species. These findings suggest that human responses to exogenous insulin may express a limited number of VH genes and depend upon somatic mutation and complex D gene interactions in CDRH3 to expand the repertoire. Although these antibodies bind autologous insulin, VH gene usage and structural features that predominate in the response are not characteristic of the fetal repertoire.
MHC class I expression on tumor targets inhibits natural killer cell-mediated cytotoxicity without interfering with target recognition.
Authors: Kaufman D S , Schoon R A , Leibson P J 
Published: December 2022

Abstract
NK cell-mediated killing is inversely proportional to the amount of MHC class I expression on certain tumor targets. Two hypotheses have been proposed to explain why class I-bearing targets are more resistant to NK cell-mediated lysis: 1) the presence of class I prevents NK cell recognition of a triggering molecule on the target cell surface, or 2) class I recognition transmits a separate inhibitory signal to the NK cell. To differentiate between these potential mechanisms, we have used cloned human CD16+/CD3- NK cells, the class I-deficient cell line C1R, and C1R cells expressing high levels of transfected HLA class I gene products. If class I expression blocks NK cell recognition of the targets, then proximal cell signaling events such as phospholipase C-mediated hydrolysis of membrane phosphoinositides should be decreased in the NK cells interacting with the class I transfectants. However, we found that increases in the level of target cell class I expressions did not decrease phosphoinositide turnover or calcium signaling in NK cells. We also examined the effect of treating HLA-transfected C1R cells with mAb specific for the transfected MHC class I gene product. If class I expression has a negative regulatory influence on NK cell activation, then treating the targets with anti-HLA mAb should block the transmission of this negative signal. Consistent with this notion, addition of anti-HLA mAb (either whole Ig or F(ab')2 fragments) led to increased lysis of the class I-transfected targets. In contrast, addition of isotype-matched mAb specific for other cell surface markers did not alter sensitivity to lysis. All of these results suggest that MHC class I expression on target cells can initiate inhibitory signals in NK cells without blocking access to target structures.
Catecholamines stimulate MHC class I, class II, and invariant chain gene expression in brain endothelium through different mechanisms.
Authors: Bourdoulous S , Durieu-Trautmann O , Strosberg A D , Couraud P O 
Published: December 2022

Abstract
Bovine brain microvessel endothelial cells in primary culture retain a differentiated phenotype reminiscent of the in vivo blood-brain barrier endothelium. The IFN-gamma-induced surface expression of MHC class II molecules on those cells is stimulated by catecholamines through a cAMP-independent mechanism. We report that both the induction of MHC class II molecule expression by IFN-gamma and its potentiation by isoproterenol, a catecholamine analog, are preceded by increases of steady-state levels of the corresponding mRNA. Similar results were obtained for the regulation of invariant chain expression. In addition, isoproterenol alone is able to increase class I mRNA levels, but, in contrast to what is observed for class II expression, this effect appears to be mainly mediated by cAMP. These studies demonstrate that, in bovine brain microvessel endothelial cells, catecholamines up-regulate MHC class I and class II Ag, as well as invariant chain with different kinetics and through different mechanisms and suggest that these regulatory effects occur at the transcriptional level.
In vitro production of IL-6, IL-1 beta, and tumor necrosis factor-alpha by human embryonic microglial and neural cells.
Authors: Sébire G , Emilie D , Wallon C , Héry C , Devergne O , Delfraissy J F , Galanaud P , Tardieu M 
Published: December 2022

Abstract
The abilities of the different cells from human central nervous system (CNS) to produce IL-6, IL-1 beta, and TNF-alpha were tested in vitro using either cultures enriched in human embryonic microglial cells or primary cultures of human embryonic CNS cells. High amounts of IL-6, low amounts of IL-1 beta but no TNF-alpha were detected in supernatants of microglial cells, kept either in FCS-free conditions or in FCS-containing medium. Moreover, IL-6 mRNA was also present in 45 to 55% of microglial cells cultured in the presence of FCS as visualized by in situ hybridization, whereas IL-1 beta mRNA remained undetectable. After prestimulation of microglial cells with LPS or IL-1 alpha, the percentage of cells labeled with an antisense IL-6 mRNA probe increased to 70% and hybridization with an antisense IL-1 beta mRNA probe became detectable. In contrast to this dyscoordinate production of cytokines by microglial cells, human monocytes, freshly isolated from blood and kept in the same culture conditions, produced high levels of the three cytokines tested. In primary cultures of human embryonic CNS cells, IL-6, IL-1 beta, and TNF-alpha were produced mostly or only by microglial cells because no IL-1 beta mRNA or IL-6 mRNA were detected in astrocytes, even after prestimulation with LPS or IL-1 alpha. Finally, IL-1 was the main inducer of IL-6 production because IL-1 alpha, but not LPS, induced a significant increase in IL-6 synthesis in cultures kept in FCS-free medium. However, in presence of FCS, LPS appeared to initiate a cascade reaction involving the production of IL-1 by microglial cells, acting as an autocrine loop to trigger IL-6 synthesis.
Anti-CD3:anti-IL-2 receptor bispecific monoclonal antibody. Targeting of activated T cells in vitro.
Authors: MacLean J A , Su Z , Guo Y , Sy M S , Colvin R B , Wong J T 
Published: December 2022

Abstract
T cells are major mediators of graft rejection and many autoimmune diseases. During the Ag recognition process, T cells often become activated. We tested the hypothesis that an anti-CD3:anti-CD25 (CD3,25) bispecific mAb (BSMAB) can effectively and selectively target activated T cells. By flow cytometric analysis, the CD3,25 BSMAB was shown to bind avidly to activated T cells that coexpress CD3 and CD25 (p55 chain of the IL-2R), achieving higher levels than the parent anti-CD3 and anti-CD25 mAb. It bound only weakly to unstimulated T cells. The CD3,25 BSMAB effectively redirected CTL to lyse CD25-bearing PHA-stimulated T lymphoblasts and the IL2-dependent CTLL tumor cell line in chromium release assays. It was highly effective in blocking MLR as shown by inhibition of [3H]TdR incorporation. However, the CD3,25 BSMAB has a low potential to activate resting T cells, as it induced only minimal [3H]TdR incorporation even in the presence of exogenous IL-2. In the absence of exogenous IL-2, the CD3,25 BSMAB was unable to induce [3H]TdR incorporation. In contrast, the parent anti-CD3 mAb induced a high degree of incorporation. In summary, the CD3,25 BSMAB selectively targets activated CD25-expressing T cells and lymphomas although maintaining a low activation potential for unstimulated T cells, potentially advantageous properties that can be exploited for immunotherapy.
Regulation of protein kinase C isoform proteins in phorbol ester-stimulated Jurkat T lymphoma cells.
Authors: Tsutsumi A , Kubo M , Fujii H , Freire-Moar J , Turck C W , Ransom J T 
Published: December 2022

Abstract
Activation of protein kinase C (PKC) in T cells leads to a variety of responses including IL-2 production and IL-2 receptor expression. PKC consists of several isoforms that exhibit some different in vitro properties. We have set up a Western blotting system to explore the regulation of PKC isoforms during T cell activation. In Jurkat T lymphoma cells, PKC alpha, beta, delta, epsilon, and zeta were detected. PKC alpha and beta existed primarily in the cytosol, translocated to the membrane fraction after 10 minutes of treatment with PMA, and almost completely disappeared within 16 h. A larger fraction of PKC delta and epsilon existed in the membrane fraction compared to PKC alpha or beta, and PKC epsilon translocated to the membrane fraction rapidly. Translocation of PKC delta was not apparent after 1 h treatment with PMA, but total PKC delta protein was reduced within 4 to 6 h of treatment. Consistent with this, overnight treatment with PMA caused down-regulation of both PKC delta and epsilon, but to a lesser degree than was observed with PKC beta. Anti-PKC zeta antibody detected two bands at 82 and 75 kDa. The 75-kDa band existed mostly in the cytosol fraction and showed no translocation or down regulation after PMA. We present evidence that this 75-kDa band represents PKC zeta. Similar PMA-induced translocation responses were observed in murine thymocytes showing that the responses are not unique to PKC isoforms in Jurkat. These results demonstrate that it is possible for the PKC isoforms to be differentially regulated during T cell activation.
Direct demonstration of membrane IL-1 alpha on the surface of circulating B lymphocytes and monocytes.
Authors: Zola H , Flego L , Wong Y T , Macardle P J , Kenney J S 
Published: December 2022

Abstract
A mAb against IL-1 alpha has been used in a high sensitivity immunofluorescence procedure to demonstrate directly the presence of surface IL-1 alpha on human monocytes and B cells from blood and tonsil. IL-1 alpha could be detected on monocytes and a subset (around 30%) of B cells without any in vitro activation. Although the subset of B cells expressing IL-1 alpha was distinct (i.e., the distribution of fluorescence intensity was bimodal), no correlation was seen with any other B cell subset marker in blood. In tonsil, IL-1 alpha was expressed by cells with a phenotype that suggested that they represented a subset of mantle zone B cells. Activation of tonsil B cells with anti-IgM, IL-4, IL-2, and mixtures of these reagents led to small increases in IL-1 alpha expression, as did activation of unfractionated tonsil cells with PHA.
Production of transforming growth factor-beta by Mycobacterium avium-infected human macrophages is associated with unresponsiveness to IFN-gamma.
Authors: Bermudez L E 
Published: December 2022

Abstract
Transforming growth factor-beta 1 (TGF-beta 1) is a potent immunoregulatory molecule. It modulates production of cytokines, such as TNF-alpha and IL-6, and cell response to cytokine stimulation. Mycobacterium avium is an intracellular bacterium that multiplies within macrophages. The reason why M. avium can survive within macrophages is still unknown but probably is multifactorial. Exposure of M. avium-infected macrophages to rTGF-beta 1 before TNF stimulation significantly decreases the mycobactericidal/mycobacteriostatic activity associated with treatment with TNF. Infection of human monocyte-derived macrophages in vitro with M. avium strains belonging to serovars 1, 4, and 8 induced secretion of biologically active TGF-beta. The production of TGF-beta was strain dependent and was more pronounced in macrophages infected with virulent strains. Incubation of macrophages with M. avium-derived 33-kDa and 65-kDa proteins was associated with significant release of biologically active TGF-beta. Treatment of M. avium-infected macrophages with rTNF-alpha in the presence of anti-TGF-beta 1 antibody induced significantly greater killing of M. avium than did treatment of macrophages with TNF-alpha in the absence of anti-TGF-beta 1 antibody. In addition, macrophage monolayers treated with anti-TGF-beta 1 antibody before infection with M. avium showed mycobactericidal activity after stimulation with rIFN-gamma; in contrast, no effect of IFN-gamma was seen in monolayers not treated with anti-TGF-beta 1 antibody. We conclude that TGF-beta 1 produced after M. avium infection is a potent inhibitor of macrophage activation by cytokines. This inhibition may have an important role in the regulation of the immune response against M. avium.
Human peripheral gamma delta T cells recognize hsp60 molecules on Daudi Burkitt's lymphoma cells.
Authors: Kaur I , Voss S D , Gupta R S , Schell K , Fisch P , Sondel P M 
Published: December 2022

Abstract
Studies with the use of polyclonal rabbit antiserum reactive with 60-kDa heat shock proteins (hsp60) suggested that hsp60-related molecules could be found on the surface of Daudi cells and were involved in their recognition by certain human gamma delta T cells. The present study confirms this finding by using a mAb specifically recognizing hsp60. This mAb can block outgrowth of human gamma delta T cells in response to stimulation with Daudi and in response to an extract of the mycobacteria H37Ra. This anti-hsp60 mAb stains the surface of Daudi cells, but does not stain either Raji or EBV-transformed B cells, cells which do not stimulate gamma delta T cell outgrowth. Anti-hsp60 mAb could immunoprecipitate a 60-kDa molecule from the H37Ra extract but was unable to precipitate this 60-kDa molecule if the mAb was first absorbed on Daudi cells. This mAb also precipitated a 60-kDa molecule from the surface of Daudi cells which shows an electrophoretic mobility pattern consistent with hsp60. These experiments demonstrate that human gamma delta T cells recognize hsp60-related epitopes on the surface of Daudi cells and within mycobacterial extracts.
Age-dependent V region expression in the human antibody response to the Haemophilus influenzae type b polysaccharide.
Authors: Lucas A H , Azmi F H , Mink C M , Granoff D M 
Published: December 2022

Abstract
The human L chain antibody repertoire specific for the Haemophilus influenzae type b (Hib) polysaccharide (PS) is composed of kappa I, kappa II, kappa III, kappa IV, and lambda L chain V regions, but the most commonly occurring VL is encoded by the unmutated V kappa II-A2 gene. To determine whether this VL repertoire is influenced by age, we used idiotypic probes to monitor V kappa II-A2, V lambda, and V kappa III usage in the antibody response to an Hib PS-protein conjugate vaccine. A single dose of a vaccine consisting of Hib PS coupled to an outer membrane protein complex of Neisseria meningitidis was administered. Adults (n = 35), 18-month-old infants (n = 35), and 2-month-old infants (n = 46), all with &gt; or = 0.9 microgram/ml anti-Hib PS antibodies, were tested for VL region markers in postvaccination sera. V kappa III anti-Hib PS antibodies were not detected in any of the 2-month-old infants but were detected in 29% of the 18-month-old infants and 69% of the adults (p &lt; 0.001). The lack of kappa III antibodies in 2-month-old infants could not be accounted for by lack of a kappa response, because kappa antibodies to Hib PS were present (&gt; 0.15 microgram/ml) in 45% of these infants. Hibld-1, an idiotope expressed by anti-Hib PS antibodies having the kappa II-A2 V region, was present in postvaccination sera of 66% of the adults and 80% of the 18-month-old infants but was less frequent in the 2-month-old infants (35%, p &lt; 0.001). In contrast, Hibld-2, which is an idiotope expressed by a subset of V lambda VII anti-Hib PS antibodies, was rare or infrequent in adults and 18-month-old infants (0% and 6%, respectively) but was present in 43% of 2-month-old infants (p &lt; 0.001). Our findings demonstrate that dramatic changes in VL region utilization occur in the human antibody response to this Hib PS conjugate vaccine as a function of age. Because previous studies have shown that V region usage correlates with antibody fine specificity and avidity for Hib PS, these age-related differences in V region expression may affect the ability of vaccines to confer protective immunity at different ages.
Inhibition of IL-2-dependent proliferation by a prostaglandin-dependent suppressor factor.
Authors: Ferreri N R , Herzog W R , Askenase P W 
Published: December 2022

Abstract
In the picryl chloride contact sensitivity system in mice, i.v. injections of trinitrobenzene sulfonic acid (TNBSA) prevents elicitation of delayed-type hypersensitivity reactions. This suppression is due in part to a non-specific, PG-dependent factor (TNBSA-F) that is induced by i.v. injection of TNBSA and is produced by pooled spleen and lymph node cells in vitro. Inasmuch as a role for lymphokines such as IL-2 has been postulated in delayed-type hypersensitivity, we determined the in vitro effects of TNBSA-F on the responsiveness of HT-2 target cells to IL-2. TNBSA-F induced a dose-dependent unresponsiveness of HT-2 cells to IL-2. The inhibitory activity was not present in supernatants from lymphoid cells of sham-treated mice. In the presence of indomethacin, spleen, and lymph node cells from TNBSA-immunized mice produced a factor whose activity was much reduced compared to TNBSA-F. This suggested that PG were required for TNBSA-F activity. However, PG alone did not induce the unresponsiveness because TNBSA-F but not sham-treated mice had inhibitory activity despite containing similar levels of PGE2. Rather, the combination of i.v. TNBSA injections and PG synthesis during production of TNBSA-F were required to produce a suppressive TNBSA-F. The inhibitory effect of TNBSA-F was not due to the presence of transforming growth factor-beta, soluble immune-response suppressor, INF-gamma, or JE in the factor preparation. Partial characterization showed a single peak of in vitro TNBSA-F activity (molecular mass approximately 35-55 kDa) by Sephadex G-200 gel filtration chromatography and by HPLC. In addition, TNBSA-F retained its activity after multiple cycles of freeze-thaw and heating for 1 h at 56 degrees C. The inhibitory effects of TNBSA-F on IL-2-induced proliferation suggest that suppression of delayed type hypersensitivity after i.v. administration of TNBSA may, in part, be due to a PG-dependent suppressor factor that inhibits the responsiveness of target cells to IL-2.