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Biomedical subjects

J Banchereau

Publications and source records attributed to J Banchereau.

At least 163 records · Page 9Linked to original sources
PubMed1995

Memory B cells from human tonsils colonize mucosal epithelium and directly present antigen to T cells by rapid up-regulation of B7-1 and B7-2.

Human memory B cells that carry mutated IgV region genes were isolated from tonsils by negative selection of IgD+ naive B cells and CD38+ germinal center B cells and plasma cells. They were mainly found within the intraepithelial areas, but not in the B cell follicles of human tonsils. Memory B cells but not naive B cells have the capacity to present antigen directly to T cells, owing to the constitutive expression of the accessory molecules B7-1/CD80 and B7-2/CD86. Signals through antigen receptors and CD40 antigen result in these two molecules being further up-regulated more rapidly and strongly on memory B cells than on naive B cells. The unique anatomical localization of memory B cells beneath the surface of mucosa, together with their strong APC capacity, may explain the well-known prompt and robust secondary antibody responses.

Antigen-Presenting Cells↗
PubMed1995

T cell-induced B cell blasts differentiate into plasma cells when cultured on bone marrow stroma with IL-3 and IL-10.

B lymphocytes activated by T cells in secondary lymphoid organs mature into plasma cells after migration into the medullary cords of these organs, mucosal lamina propria or bone marrow. To analyze each step leading to plasma cell generation, we set up a two-step culture system of purified tonsillar B cells. In a primary stage, B cell blasts were generated by co-culturing B cells with an irradiated T cell clone activated with immobilized anti-CD3. In a secondary step, culturing these blasts on bone marrow stromal cells (BMSC) induced them to secrete large amounts of IgG, as well as some IgM and IgA. Other fibroblast-like cell lines were less efficient at sustaining the differentiation of blasts into Ig-secreting cells, suggesting that these are specific properties of BMSC. Addition of IL-3 and IL-10 further stimulated IgG secretion by B cell blasts cultured on BMSC, mostly the IgG1 subclass. These two cytokines probably acted through different pathways, as (i) the effect of IL-3 but not IL-10 was dependent upon prolonged T cell pre-activation and (ii) their combined stimulatory effect was additive. B cell blasts cultured on BMSC with a combination of IL-3 and IL-10 differentiated into non-proliferating plasma cells as determined by poor thymidine incorporation, typical cellular morphology, intense expression of intracytoplasmic Igs, very high levels of surface CD38 and lack of surface CD20.

Adult↗
PubMed1995

Long-term cultured CD40-activated B lymphocytes differentiate into plasma cells in response to IL-10 but not IL-4.

We compared the effects of IL-10 and IL-4 on the functions of B lymphocytes triggered through their CD40. During the initial phase, IL-10 was as potent as IL-4 in inducing the expansion of viable B cells. Then, cellular expansion slowed down and after approximately 3 weeks the number of B cells started to decline. While the combination of IL-10 and IL-4 was synergistic during the first 2 weeks of culture, B cell recovery declined after 3 weeks, indicating that IL-10 prevails over IL-4. Those effects were not restricted to a specific B cell subset as both sIgD+ B cells and sIgD- B cells behaved in a similar way, though the latter population responded with a slightly accelerated kinetic. Inverted microscope examination and scanning electron microscopy showed that in response to IL-10, CD40-activated B cell cultures were heterogeneous with loose aggregates of cells as well as free floating large ovoid cells. In contrast, in the presence of IL-4, CD40-activated B cell cultures were essentially composed of tight cell clumps. IL-10 progressively induced all B cells to differentiate into non-replicating cells with intracytoplasmic Ig that secreted Ig at a high rate. Cytologic analysis indicated that IL-10 cultured cells display a basophilic cytoplasm with an arcoplasm and a low nucleus/cytoplasm ratio. Transmission electron microscopy demonstrated that when IL-10 was added to the culture, B cells displayed structures for excretion with extended endoplasmic reticulum and dilated cisternae containing paracrystalline structures, typical of plasmablasts cells. Taken together, these results indicate that IL-10 acts as a plasma cell differentiation factor for CD40-activated B cells.

Antibody-Producing Cells↗
PubMed1995

The ability of synoviocytes to support terminal differentiation of activated B cells may explain plasma cell accumulation in rheumatoid synovium.

To understand the accumulation of plasma cells within RA synovium, the ability of rheumatoid synoviocytes to support the differentiation of B cells into plasma cells was explored. Tonsillar B lymphocytes cultured over confluent monolayers of synoviocytes, secreted threefold more Igs (mainly IgM) than B cells cultured directly on plastic well. More importantly, synoviocytes enhanced by 14-fold the production of Igs (mainly IgG) by B cells costimulated with Staphylococcus aureus Cowan (SAC) particles. IL-10 and, in a lower extent, IL-2 increased Ig secretion in cocultures, and their combination was synergistic. In the presence of SAC, IL-2, and IL-10, synoviocytes increased by 13-884-fold the production of IgG, which reached 0.19 ng/cell per day. RA as well as normal synoviocytes were more potent than other adherent cell lines to support terminal B cell differentiation. Synoviocyte activity involved both a support of B cell survival, and an induction of the terminal differentiation of B cells into mature plasma cells with typical morphology, high levels of intracytoplasmic Igs, and CD20- CD38high surface expression. The present observation should permit the identification of molecules involved in the maturation of B cells into plasma cells, and in their accumulation in rheumatoid synovium.

Antibodies, Monoclonal↗
PubMed1995

CD40-activated human naive surface IgD+ B cells produce IgG2 in response to activated T-cell supernatant.

Human IgG2 is an isotype associated with immune responses to carbohydrates. While interleukin-10 (IL-10) induced CD40-activated naive surface (s)IgD+ human B cells to secrete IgG1 and IgG3, none of 20 recombinant cytokines tested alone, or in combination with IL-10, was able to induce these cells to produce IgG2. This was not due to a specific inability of these sIgD+ B cells, as they could be induced to secrete microgram amounts of IgG2, as well as the three other IgG subclasses, when cultured with an anti-CD3-activated CD4+ T-cell clone. The supernatant of this activated CD4+ T-cell clone contained a soluble factor(s) able to induce the secretion of IgG2 by CD40-activated sIgD+ B cells. Following activation, blood T cells also produced a factor(s) inducing CD40-activated naive B cells to secrete IgG2. This CD4+ T-cell clone will thus permit us ultimately to define the presently uncharacterized cytokine(s) inducing naive B cells to secrete IgG2. This will provide a new insight for the study of immunodeficiencies involving a selective defect in IgG2.

B-Lymphocytes↗
PubMed1995

Converging and diverging properties of human interleukin-4 and interleukin-10.

IL-4 and IL-10 are both produced by activated TH2 cells as well as basophil/mast cells. In addition, IL-10 is secreted by activated B cells, monocytes/macrophages and keratinocytes. IL-4 and IL-10 act in concert to induce activated B lymphocytes to grow, switch isotype and ultimately differentiate into antibody producing plasma cells. Both IL-4 and IL-10 inhibit the secretion of proinflammatory cytokines by monocytes/macrophages and neutrophils. While IL-4 enhances the presentation of antigen by monocytes/macrophages and dendritic cells, IL-10 inhibits it. IL-4 and IL-10 can either stimulate or inhibit T cell proliferation. While both cytokines may prove useful in the management of inflammatory disorders, IL-4 is presently used in clinical trials that relate to its antitumor effects.

Animals↗
PubMed1995

Proliferation of MIELIKI a novel t(7;9) early pre-B acute lymphoblastic leukemia cell line is inhibited concomitantly by IL-4 and IL-7.

The present study describes a novel cell line, MIELIKI, established from bone marrow of a pediatric patient with B lineage acute lymphoblastic leukemia (ALL) at diagnosis. The MIELIKI cell line displays an early pre-B cell phenotype (CD10+, CD19+, CD20+, CD34-, Cmu-, sIg-) with rearrangements on both Ig heavy chain and k light chain alleles, and carries an unfrequent t(7;9) chromosomal translocation identical to the freshly isolated leukemic blasts. The proliferation of MIELIKI cells was abrogated by IL-4 and by IL-7, as measured by DNA replication and viable cell recovery. The effects of IL-4 and IL-7 were mediated, respectively, through the CDw124 and CDw127 IL-4 and IL-7 receptor components. Growth inhibition by IL-4 was not mediated by soluble factors released by MIELIKI cells in response to IL-4, suggesting the existence of an intrinsic negative signaling pathway. Finally, neither IL-4 nor IL-7 were found to induce maturation of MIELIKI into cells expressing cytoplasmic or surface membrane mu chain. The present cell line should constitute a useful model of t(7;9) early pre-B ALL and allow investigation of the relationship between IL-4 and IL-7 negative signaling in leukemic B cell ontogeny.

Antigens, CD↗
PubMed1994

B70/B7-2 is identical to CD86 and is the major functional ligand for CD28 expressed on human dendritic cells.

Dendritic cells comprise a system of highly efficient antigen-presenting cells involved in the initiation of T cell responses. Herein, we investigated the role of the CD28 pathway during alloreactive T cell proliferation induced by dendritic-Langerhans cells (D-Lc) generated by culturing human cord blood CD34+ progenitor cells with granulocyte/macrophage colony-stimulating factor and tumor necrosis factor alpha. In addition to expressing CD80 (B7/BB1), a subset of D-Lc expressed B70/B7-2. Binding of the CTLA4-Ig fusion protein was completely inhibited by a combination of monoclonal antibodies (mAbs) against CD80 and B70/B7-2, indicating the absence of expression of a third ligand for CD28/CTLA-4. It is interesting to note that mAbs against CD86 completely prevented the binding of CTLA4-Ig in the presence of mAbs against CD80 and bound to a B70/B7-2-transfected fibroblast cell line, demonstrating that the B70/B7-2 antigen is identical to CD86. CD28 triggering was essential during D-Lc-induced alloreaction as it was inhibited by mAbs against CD28 (9 out of 11 tested). However, none of six anti-CD80 mAbs demonstrated any activity on the D-Lc-induced alloreaction, though some were previously described as inhibitory in assays using CD80-transfected cell lines. In contrast, a mAb against CD86 (IT-2) was found to suppress the D-Lc-dependent alloreaction by 70%. This inhibitory effect was enhanced to > or = 90% when a combination of anti-CD80 and anti-CD86 mAbs was used. The present results demonstrate that D-Lc express, in addition to CD80, the other ligand for CTLA-4, CD86 (B70/B7-2), which plays a primordial role during D-Lc-induced alloreaction.

Abatacept↗
PubMed1994

Activation of human dendritic cells through CD40 cross-linking.

Dendritic cells, the professional antigen-presenting cells (APC) involved in T cell priming, express CD40, a molecule which triggering plays a key role in B cell growth and differentiation as well as monocyte activation. Herein we demonstrate that dendritic Langerhans cells (D-Lc) generated by culturing cord blood CD34+ progenitor cells with granulocyte/macrophage colony-stimulating and tumor necrosis factor alpha (TNF-alpha) express functional CD40 at a density higher than that found on B cells. Culturing D-Lc on CD40-ligand (CD40L) transfected L cells allowed D-Lc survival as 50 +/- 15% of seeded cells were recovered after 4 d while only 5% survived over control L cells. CD40 activation induced important morphological changes with a reduction of cytoplasmic content and a remarkable increase of dendrite development as well as an altered phenotype. In particular, CD40 triggering induced maintenance of high levels of major histocompatibility complex class II antigens and upregulation of accessory molecules such as CD58, CD80 (B7-1) and CD86 (B7-2). CD40 engagement also seems to turn on D-Lc maturation as illustrated by upregulation of CD25, a molecule usually expressed on interdigitating dendritic cells of secondary lymphoid organs. Finally, CD40 activated D-Lc secreted a limited set of cytokines (TNF-alpha, IL-8, and macrophage inflammatory protein 1 alpha [MIP-1 alpha]) whereas a similar activation induced elutriated monocytes to secrete IL-1 alpha, IL-1 beta, IL-6, IL-8, IL-10, TNF-alpha, and MIP-1 alpha. As D-Lc activated T cells upregulated CD40L, it is likely that CD40 activation of D-Lc observed herein with a fibroblast cell line stably expressing CD40L, mimics physiological interactions between dendritic cells and T cells.

Adult↗
PubMed1994

Interleukin-13 inhibits the proliferation of normal and leukemic human B-cell precursors.

Interleukin-13 (IL-13) is a T-cell-derived cytokine that displays homology with IL-4 and shares some of its biologic functions. We investigated the effects of IL-13 on normal human B-cell precursors (BCP) and their malignant counterparts in B-lineage acute lymphoblastic leukemia (BCP-ALL). IL-13 inhibited growth of CD19+ slg- normal BCP cultured in the presence or absence of bone marrow accessory stromal cells and IL-7. In addition, IL-13 inhibited proliferation of blasts isolated from leukemic patients and cells from established BCP-ALL lines. Differences were observed in a number of cases with respect to growth inhibition in response to IL-13 and IL-4. These results suggest heterogeneity in the expression of IL-13 and IL-4 receptors in B-cell ontogeny. Growth-inhibition by IL-13 could be reverted by anti-IL-4 receptor antibody, indicating that the IL-13 and IL-4 binding chains can be closely associated on BCP. We further showed that the inhibitory effect of IL-13 results from decreased cell-cycle activity. Finally, whereas IL-13 induced CD23 expression on BCP-ALL cells, it did not promote differentiation into slg+ B lymphocytes.

B-Lymphocytes↗
PubMed1994

Human monoclonal autoantibodies specific for the bullous pemphigoid antigen 1 (BPAg 1).

Bullous pemphigoid (BP) is an acquired blistering skin disease associated with the production of IgG autoantibodies to the 230-kDa BP Ag (BPAg1). To better characterize the epitopes of BPAg1, we generated immortalized B cell lines secreting human mAbs (HumAbs) to BPAg1 from two BP patients whose sera reacted with native BPAg1 but not with a recombinant BP55 carboxyl-terminal peptide. Ab-producing B cell lines were established by EBV infection of CD40-activated PBMCs. Three independent clonal lines were obtained that secreted IgG HumAbs, including one IgG1 kappa (BP3) and two distinct IgG4 kappa (BP1 and BP2). These three HumAbs immunoprecipitated BPAg1. Blocking immunofluorescence experiments and phylogenetic studies showed that these Abs recognize different epitopes of BPAg1. This analysis with HumAbs further extends the serologic demonstration of the wide variety of epitopes recognized by BPAg1 autoantibodies which contrasts with the limited number of epitopes recognized by thyroid peroxidase monoclonal autoantibodies.

Antibodies, Monoclonal↗
PubMed1994

Analysis of somatic mutation in five B cell subsets of human tonsil.

Using a series of phenotypic markers that include immunoglobulin (Ig)D, IgM, IgG, CD23, CD44, Bcl-2, CD38, CD10, CD77, and Ki67, human tonsillar B cells were separated into five fractions representing different stages of B cell differentiation that included sIgD+ (Bm1 and Bm2), germinal center (Bm3 and Bm4), and memory (Bm5) B cells. To establish whether the initiation of somatic mutation correlated with this phenotypic characterization, we performed polymerase chain reaction and subsequent sequence analysis of the Ig heavy chain variable region genes from each of the B cell subsets. We studied the genes from the smallest VH families (VH4, VH5, and VH6) in order to facilitate the mutational analysis. In agreement with previous reports, we found that the somatic mutation machinery is activated only after B cells reach the germinal center and become centroblasts (Bm3). Whereas 47 independently rearranged IgM transcripts from the Bm1 and Bm2 subsets were nearly germline encoded, 57 Bm3-, and Bm4-, and Bm5-derived IgM transcripts had accumulated an average of 5.7 point mutations within the VH gene segment. gamma transcripts corresponding to the same VH gene families were isolated from subsets Bm3, Bm4, and Bm5, and had accumulated an average of 9.5 somatic mutations. We conclude that the molecular events underlying the process of somatic mutation takes place during the transition from IgD+, CD23+ B cells (Bm2) to the IgD-, CD23-, germinal center centroblast (Bm3). Furthermore, the analysis of Ig variable region transcripts from the different subpopulations confirms that the pathway of B cell differentiation from virgin B cell throughout the germinal center up to the memory compartment can be traced with phenotypic markers. The availability of these subpopulations should permit the identification of the functional molecules relevant to each stage of B cell differentiation.

Antigens, CD↗
PubMed1994

Growth inhibitory and agonistic signals of interleukin-7 (IL-7) can be mediated through the CDw127 IL-7 receptor.

The present study was aimed at identifying surface-membrane molecules involved in the regulation of human B-cell ontogeny. For this purpose, murine monoclonal antibodies (MoAbs) were generated against Pre-Alp, a pre-B acute lymphoblastic leukemia (ALL) cell line, and MoAb R34.34 was selected for further characterization. R34.34 recognized a molecule expressed on normal B-cell precursors (BCP) but not on mature B cells. The antibody also reacted with T lymphocytes, a subpopulation of monocytes from peripheral blood, and a subset of CD34+ cells. Immunoprecipitation analysis indicated that R34.34 recognizes an 80-kD molecular weight antigen. Antibody R34.34 was further found to be directed against an epitope interfering with binding of interleukin-7 (IL-7) to Pre-Alp cells. Expression cloning from a Pre-Alp cDNA library showed that R34.34 antigen is CDw127, the 75- to 80-kD IL-7 receptor. Proliferation of the B-lineage ALL cell lines Reh and Mieliki was inhibited by IL-7, and this effect was specifically reverted by MoAb R34.34. In addition, antibody R34.34 specifically inhibited IL-7-dependent proliferation of normal BCP, Pre-Alp cells, and peripheral T cells. These results imply that both inhibitory and proliferative effects of IL-7 can be mediated through the same receptor on various lineages. R34.34 antibody should be important for the analysis of signal transduction through CDw127.

Adult↗