PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “B cells”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1990

Functional human T cell-B cell hybridomas established from fusion of normal T cells and an EBV-transformed B cell line.

Human T cell-B cell hybridomas containing 92 chromosomes were derived by fusing normal stimulated CD-depleted T cells with the EBV-transformed human B cell line 729-HF. These hybridomas coexpressed the T cell surface markers CD3, CD8, and CD2 and the B cell surface antigens CD19, CD20, CD23, DR, and DQ. They weakly and variably expressed surface IgM and TCR. Genomic analysis revealed the presence of rearranged Ig genes as well as beta-T cell receptor genes that could be ascribed to the B and T cell parent, respectively. Analysis of TCR rearrangement suggests that the T-B hybridomas are, in fact, subclones of a single dominant clone. Although the hybrids expressed CD8 and not CD4, following preincubation with PWM, some the of clones induced IgG synthesis from normal B cells while the parent B cell line failed to demonstrate this activity. Stimulation of the hybridomas with PMA down-regulated the T cell lineage-specific antigen display (CD3, CD8, and TCR) and increased IgM production from the hybrids without changing B cell surface antigen display. These hybridomas may be useful to dissect the steps involved in the ultimate commitment of a cell to the B or T cell lineages and will be made available to interested investigators.

Antigens, CD↗
PubMed1992

Expression and distribution of CD11a/CD18 and CD54 during human T cell-B cell interactions.

Interactions between intercellular adhesion molecule 1 (ICAM-1, CD54) and leukocyte function-associated antigen 1 (LFA-1, CD11a/CD18) play a critical role in T cell-B cell collaboration. The current experiments were carried out to determine the expression and distribution of these adhesion molecules on human peripheral T cells and B cells during T cell-B cell collaboration. Resting CD4+ T cells were largely ICAM-1 negative, whereas immobilized anti-CD3 monoclonal antibody (mAb) rapidly induced ICAM-1 expression. By contrast, most B cells expressed ICAM-1 before activation, and further increases in density were noted with stimulation. Both B cells and CD4+ T cells expressed LFA-1 before activation, although the density on CD4+ T cells was considerably greater. A double staining method for electron microscopic analysis was developed that permitted analysis of the expression and distribution of ICAM-1 to be assessed during T cell-B cell collaboration. Under the experimental conditions examined, B cells showed a uniform distribution of ICAM-1. In contrast, ICAM-1 was highly mobile on the surface of CD4+ T cells. If the T cells were not fixed, staining, even at 4 degrees C, caused rapid redistribution of ICAM-1 into aggregates. However, by fixing cells before the staining procedures, the distribution of ICAM-1 on CD4+ T cells could be accurately assessed. Most (85%) of the fixed activated CD4+ T cells showed a uniform distribution of ICAM-1. However, when activated CD4+ T cells were cocultured with B cells, redistribution of ICAM-1 on CD4+ T cells but not B cells occurred, such that the majority (85%) was found at or immediately adjacent to the point of attachment to the B cells. No redistribution of LFA-1 on either T cells or B cells was found. These findings suggest that rapid changes in density of ICAM-1 expression and the mobility of ICAM-1 on activated T cells may play a role in providing activation signals to B cells during T cell-B cell collaboration.

Antigens, CD↗
PubMed1990

Production of cytokines by mouse B cells: B lymphomas and normal B cells produce interleukin 10.

We have examined a panel of murine Ly-1+ B lymphomas and purified normal murine peritoneal B cells separated into subsets on the basis of expression of the Ly-1 surface antigen, for their ability to produce cytokines. Where possible, we have used a combination of cytokine detection methods in order to compensate for differences in sensitivity and specificity, and the possibility of inhibitors masking an activity. All the lymphomas tested were shown to constitutively express TGF-beta and CSIF/IL-10. In addition, varying levels of IL-6, TNF-alpha and TNF-beta, and G-CSF, were demonstrable in most of the lymphomas, and variants of one lymphoma (CH12) additionally produced varying levels of IL-3, IL-4, and GM-CSF. FACS purified normal Ly-1+ and Ly-1- peritoneal B cells, were also shown to express RNA encoding CSIF/IL-10, IL-6, TNF-alpha and TNF-beta, and very low levels of G-CSF, following stimulation with LPS. These data were supported by the detection of IL-6 and CSIF/IL-10 in supernatants from LPS-stimulated Ly-1+ and Ly-1- B cells using specific immunoassays. None of the lymphomas or B cell preparations produced IL-1 alpha, IL-2, IL-5, IL-7, or IFN-gamma. The purity of our normal B cell populations was assessed by phenotypic analysis on the FACS and also by the disappearance of certain mRNA transcripts after purification, e.g. CD4, c-fms, GM-CSF, and IFN-gamma, most of which could be detected in LPS-stimulated total peritoneal cell populations. This suggested that our B cell purification method had reduced, to a level undetectable in our assays, contaminating T cells (CD4), macrophages (c-fms, GM-CSF), and NK cells (IFN-gamma). Absence of IL-3, IL-4, IL-5, and GM-CSF expression by LPS-stimulated Ly-1+ and Ly-1- B cells reduced the concern that contaminating peritoneal mast cells could account for the observed cytokine production. We therefore believe our data provide strong support for production of a subset of cytokines by LPS-stimulated normal B cells. Both the Ly-1+ B lymphomas and normal Ly-1+ and Ly-1- B cells appear capable of expressing IL-6, TNF-alpha, TNF-beta, and CSIF/IL-10.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1990

Epstein-Barr virus (EBV) antigens processed and presented by B cells, B blasts, and macrophages trigger T-cell-mediated inhibition of EBV-induced B-cell transformation.

The ability of B cells, B blasts, and macrophages to present Epstein-Barr virion antigens to autologous T cells and trigger their capacity to inhibit Epstein-Barr virus-induced B-cell transformation was tested. Macrophages were as efficient as B cells and B blasts in presenting the virus to T lymphocytes. This function required antigen processing, because it was inhibited by chloroquine treatment and by fixation of the antigen-presenting cells immediately after viral exposure but not 18 h later. T cells exposed to the purified Epstein-Barr virus envelope antigen gp350 coupled to immunostimulating complexes also showed inhibitory function. These results suggest that recognition of processed virion antigens elicits the generation of T-cell-mediated inhibition of Epstein-Barr virus-induced B-cell transformation.

Antigens, Viral↗
PubMed1988

Function and behavior of surface immunoglobulin receptors in antigen-specific T cell-B cell interaction.

The expression and function of surface immunoglobulin (sIg) receptors was analyzed using antigen-specific monoclonal B cells and T cells. When B cells were incubated with antigen (hapten carrier), hapten-specific sIg receptor expression was greatly reduced. The specific antigen-presentation activity of the B cells was also markedly reduced. Following the removal of antigen, expression of the sIg receptors was restored to original levels within 3-4 hr. Specific antigen-presentation activity of these B cells was concomitantly restored. Reduction of sIg receptor expression and specific antigen presentation were inhibited by the addition of competing free hapten, suggesting that crosslinking of sIg receptors is required for the observed changes in sIg receptor expression and that specific antigen presentation is hapten specific. Using oligopeptide-specific Th cells, we could show the requirement for processing of antigen in the interaction between hapten-specific B cells and carrier-specific T cells. These results indicated that the expression of sIg receptors for a specific antigen and the ability to present the antigen are interrelated.

Animals↗
PubMed1987

An antigen-specific T8+ human clone of cells with a nonspecific augmenting function on the T4 cell-B cell helper interaction.

We isolated a T8+ T3+ Ia+ clone of cells from the peripheral blood mononuclear cells of a healthy subject. The clone was expanded and maintained with autologous feeder cells, interleukin 2, and a streptococcal antigen. The T8+ clone of cells responded specifically to the streptococcal antigen, in the absence of accessory cells, and released a soluble factor. Both the cloned cells and the corresponding soluble factor expressed augmenting helper but not suppressor activity. The augmenting helper activity for B cell antibody synthesis was demonstrable only in the presence of autologous T4 cells. Although stimulation of the T8+ cloned cells was antigen-specific, the resulting soluble factor elicited nonspecific antibody synthesis in the presence of T4 and B cells. The T8+ cloned cell-derived factor was adsorbed by B cells but not by T4 cells. Preliminary studies suggest that the factor has the properties of a B cell growth factor. We suggest that the T8+ population consists of functionally heterogeneous cell subsets, some that have suppressor function and others that augment the T4+ helper-inducer activity in B cell antibody synthesis.

Antigen-Presenting Cells↗
PubMed1990

Human hematopoietic precursors in long-term culture: single CD34+ cells that lack detectable T cell, B cell, and myeloid cell antigens produce multiple colony-forming cells when cultured with marrow stromal cells.

CD34+ human marrow cells not expressing T cell-, B cell-, and myeloid cell-associated antigens (TBM-) were cloned by two-color cell sorting into culture wells containing irradiated marrow stromal cells. After 4 wk of culture, 3.7 +/- 2.1% of these cells generated colony-forming cells (CFC), with each of these cells generating 6.3 +/- 5.3 CFC. This was not due to the 0.5 +/- 0.5% CFC present in the purified CD34+ TBM- cells, as less than 1% of CFC persist in these cultures. This is the first demonstration that single immature precursor cells in human long-term cultures generate multiple CFC progeny. The immature nature of these clonable CD34+ TBM- precursors suggests their candidate status as human hematopoietic stem cells.

Antibodies, Monoclonal↗
PubMed1988

Artificial T cell:B cell conjugation. A unique approach to analyze weak cell-cell interactions.

An antibody response against a thymic-dependent Ag requires cognate recognition of the Ag by B and T cells. Functional T-B cell (T-B) interaction involves binding of Ag by B cell surface Ig, internalization and processing of Ag, expression of an Ag fragment in the context of Ia, binding of Ag/Ia by the TCR and binding of T cell-derived lymphokines by B cell lymphokine receptors. It is becoming increasingly evident that B and T cell accessory molecules also are involved in T-B interactions. To determine the role of accessory molecules in T-B collaboration, we have designed a system in which T-B interaction was artificially induced in the absence of carrier protein. TNP-modified, turkey gamma-globulin-specific, Th cells were allowed to form conjugates with TNP-specific B cells in the absence of hapten-carrier complex. Both B and T cells were induced to proliferate and B cells partially differentiated into antibody-secreting cells when B cells were cultured with TNP-modified but not unmodified T cells. The activation of B cells by TNP-modified T cells was not MHC restricted but was blocked by anti-Ia antibodies, suggesting a role for Ia distinct from Ag presentation. Furthermore, B cell proliferation was also inhibited by antibodies to L3T4 and LFA-1, suggesting a functional accessory role for these molecules in induction of B cell proliferation/differentiation.

Animals↗
PubMed1979

Enumeration of T cells, B cells and monocytes in the peripheral blood of normal and lymphocytotic cattle.

The rosette-forming capacity of bovine peripheral blood lymphocytes (PBL) was determined with dextran and 2-aminoethylisothiouronium bromide (AET)-treated sheep erythrocytes (SRBC). Both dextran and AET-enhanced rosette formation; however, AET-treated SRBC detected a larger percentage of rosette-forming cells and thus was used in this study. The specificity of rosette formation by bovine thymus-derived (T) lymphocytes was shown by (1) demonstration of rosettes and surface-membrane immunoglobulins sIg) on different cells in PBL and nylon-wool fractionated lymphocyte populations and (2) rosette formation by a large percentage (83--90%) of thymocytes from three bovine foetuses and two 14-month-old heifers. A procedure was also developed to identify bovine monocytes by latex phagocytosis and 10--30% latex-ingesting cells were detected in PBL preparations isolated by Ficoll-Hypaque flotation. The frequency of sIg-bearing latex-ingesting, and sIg-bearing latex non-ingesting cells in bovine peripheral blood was also determined. These procedures were utilized to determine the distribution of T and bone-marrow derived (B) lymphocytes in peripheral blood of normal and lymphocytotic cattle. PBL from twenty normal cattle contained approximately 63% T and 11% B (sIg+ latex non-ingesting) lymphocytes. In peripheral blood of three cattle with persistent lymphocytosis, a prodromal stage of bovine leukaemia, the percentage of B cells was elevated approximately to 59% whereas T lymphocytes decreased to 35%, thus providing additional evidence that persistent lymphocytosis is a B-cell disease.

Animals↗
PubMedDate not supplied

High affinity specific binding of vasoactive intestinal peptide to human circulating T cells, B cells and large granular lymphocytes.

We studied the specific binding of vasoactive intestinal peptide (VIP) to circulating lymphocytes (PBL) of normal subjects using the interaction of 125I-VIP with different PBL fractions and flow cytometry to detect the binding of VIP-coated polystyrene spheres to individual cells of the fractions. Enhanced binding of 125I-VIP was found with T-enriched compared to unseparated or T-depleted PBL preparations. Both CD4 and CD8 T cell-enriched suspensions showed high binding capacity, but the affinity of CD4-enriched preparation for VIP was higher. VIP-coated spheres also bound to individual T cells of PBL, but only a minority of CD4 T cells (32%) and CD8 T cells (23%) bound the spheres. 125I-VIP also specifically bound to fractions enriched for large granular lymphocytes (LGL) and B cells. A consistent proportion of CD16 marker-positive LGL bound VIP-coated spheres (24%, and approximately 15% of B cells also showed this ability. Thus there is marked heterogeneity in the ability of different phenotypes of normal human circulating lymphocytes to recognize this neuropeptide.

B-Lymphocytes↗
PubMed1977

Complement-dependent and -independent pathways of T cell-B cell cooperation.

BDF1 mice treated with CoV had markedly reduced levels (less than 20%) of native serum C3 32 hr later, whereas the frequency of splenic CR+ cells was normal. CoV treatment before immunization reduced the IgM PFC response to a T-dependent antigen (TNP-SRBC) by more than 60%. Inclusion of highly specific anti-C3 antibody had no effect on the T-dependent IgM response of CR- B cells. The residual PFC responses in cultures of unfractionated spleen cells treated with anti-C3 could be largely or completely accounted for by CR- B cells in the cultures. The effect of anti-C3 antibody was not due to cytotoxicity. These data collectively indicate that the effect of CoV on T-dependent antibody responses is due to decreased C3 in serum rather than to interaction of C receptors directly with CoV or with C3 cleavage products. They suggest the existence of at least two distinct pathways of T-B cooperation, one in which C3 is an obligatory participant and another in which it may be uninvolved.

Animals↗
PubMed1985

T cell-B cell regulation in the intestinal lamina propria in Crohn's disease.

Many patients with Crohn's disease have suppressor T cells circulating in the peripheral blood that are potent inhibitors of immunoglobulin synthesis in vitro. The purpose of this study was to examine the regulatory effects of T cells isolated from the lamina propria of patients with Crohn's disease or of patients with other diseases. Lamina propria cells were isolated from surgically resected intestine by sequential ethylenediaminetetraacetic acid and collagenase incubations. T cells were purified from lamina propria either by anti-F(ab)2' affinity columns or by a panning technique using monoclonal anti-T cell antibodies. Changes in the pokeweed mitogen-stimulated synthesis of immunoglobulin M, immunoglobulin G, and immunoglobulin A by normal peripheral blood indicator lymphocytes, as measured by sandwich enzyme-linked immunosorbent assay, was used as an index of help and suppression. Helper T-cell activity was sought by coculturing lamina propria T cells with normal peripheral blood cells plus pokeweed mitogen. Helper T-cell activity was found among lamina propria T-cell populations of patients and controls to a roughly comparable extent; help was provided for all isotypes. Suppressor T-cell activity was sought by coculturing lamina propria T-cells with normal B cells plus irradiated normal T cells plus pokeweed mitogen. No significant suppressor T-cell activity was observed in these cocultures, whether the cells were obtained from control intestine, the grossly uninvolved margin of Crohn's disease intestine, or actively inflamed Crohn's disease intestine. We conclude that suppressor T-cell activity of the sort found previously in the peripheral blood of patients with Crohn's disease is not demonstrable in the intestinal lesions of Crohn's disease. Helper T-cell activity is the predominant regulatory activity in both control and inflamed intestinal lamina propria.

Adolescent↗
PubMed1976

Differentiation of lymphoid cells: B cell as a direct target and T cell as a regulator in lipopolysaccharide-enhanced induction of immunoglobulin production.

The cells involved in the stimulatory effect of bacterial lipopolysaccharide (LPS) on the induction of immunoglobulin (Ig) production by rabbit spleen cells cultured in the absence of antigen has been analyzed. Addition of LPS caused a several-fold enhancement of both DNA synthesis and Ig production. These enhanced activities were not significantly affected by depletion of adherent cells in the spleen cell population. Although inactivation of splenic T cells by anti-thymocyte serum (ATS) treatment did not affect the enhancement of DNA synthesis due to LPS, such treatment did adversely affect the enhancement of Ig production by LPS. Furthermore, the enhancement of Ig production of ATS-treated spleen cells by LPS was found to be dependent on the number of thymocytes added. In addition, the prior incubation of ATS-treated spleen cells with LPS resulted in effective enhancement of Ig production when such ATS-treated spleen cells and thymocytes were combined after removal of LPS. An identical experiment, except that thymocytes instead of ATS-treated spleen cells received the prior incubation with LPS, did not result in enhancement of Ig production. Finally, the enhanced Ig production due to LPS was inhibited by hydroxyurea, a known inhibitor of cellular DNA synthesis. The relationship between the mitogenic activity of LPS on B cells, the regulatory function of T cells, and the enhancement of Ig production by LPS is discussed in relation to the contrasting reports concerning the cellular target of LPS.

Animals↗
PubMed1992

Follicular dendritic cell-B cell interactions in virus disease. Common localization but different cell damage caused by antibody immobilized virus?

Follicular dendritic cells (FDC) are involved in the trapping and retention of antigen-antibody complexes in lymphoid follicles. This FDC immobilized antigen is thought to be involved in the generation of memory B-lymphocytes. Follicular trapping of both Aleutian disease virus and HIV particles has been demonstrated. However as far as known their affects on FDC and follicular B-cells are completely different. It is hypothesized that the trapping of (antibody-complexed) virus particles by the FDC-network may have an important role in several virus diseases.

Aleutian Mink Disease Virus↗
PubMed1976

T cells, B cells and intermediate forms in the newborn studied by scanning electron microscopy and phosphatase marker.

Scanning electron microscopic studies of peripheral blood lymphocytes showed that percentage of T cells was lower in four cases of premature infants born between 30th and 34th week of gestation when compared with that in four cases of term infants (18.6% and 39.9% counted from 956 and 1,379 lymphocytes, respectively). The occurence of lymphocytes with intermediate patterns of surface morphology (I cells) was noted in both groups studied. Percentages of B and I cells were higher in the premature than in the term infant (26.3% and 55.1% and 20.0% and 39.1%, respectively). Analogous tendency in the T cell occurence in the premature and the term infant was demonstrated with acid phosphatase as T cell marker.

Acid Phosphatase↗
PubMed1979

Ontogeny of T cells, B cells and monocytes in the bovine foetus.

The ontogeny of lymphocyte subpopulations and monocytes was studied in developing bovine foetuses. Fifty-four bovine foetuses ranging in age from 3 to 9 months of gestation were collected and examined for the presence of thymus-derived (T lymphocytes), bone marrow-derived (B lymphocytes) and phagocytic (macrophage) cells from thymus, spleen and peripheral blood. Detection of the cells expressing T lymphocyte surface markers was done using a modified sheep red blood cell rosette assay. Lymphocytes bearing surface immunoglobulin (sIg) were detected by staining with a fluoresceinated rabbit antibody prepared against bovine IgG. The procedure used for detecting monocytes was a latex bead phagocytic assay. In the thymus, the percentage of T lymphocytes was relatively constant throughout gestation at approximately 60-70%, with B lymphocytes remaining at about 1%, whereas the phagocytic cells showed an increase from 1% at 3 months to approximately 8% at term. The spleen showed an increasing percentage of T lymphocytes, from 11% at 3 months to over 40% at term, whereas the percentage of B lymphocytes remained consistent at about 2-3% from 3 months until term. The percentage of monocytes increases from 1% at 3 months to over 20% at 9 months. Peripheral blood T lymphocytes increased steadily from approximately 1% at 3 months to 45% at term. B lymphocyte levels remained low, about 1%, throughout gestation, whereas monocytes increased from 1% at 3 months to 5% at 9 months.

Animals↗
PubMed1985

Antigen presentation by splenic B cells: resting B cells are ineffective, whereas activated B cells are effective accessory cells for T cell responses.

In this study, we have investigated the ability of splenic B cells to act as antigen-presenting cells. Previous data had established that lipopolysaccharide (LPS)-activated B cells were effective antigen-presenting cells; however, the relative capacity of resting B cells to carry out this function remains controversial. Splenic B cells from naive BALB/c mice were depleted of macrophages, dendritic cells, and T cells, and were fractionated on the basis of cell density by using Percoll gradient centrifugation. Fractions were collected from the 50/60, 60/65, and 65/72% interfaces and from greater than 72% (pellet). Cytofluorograph analysis of the fractionated B cells showed that the two lower density fractions (50/60 and 60/65) contained a number of cells which, by cell size determination, appeared to be activated B cells, whereas the two higher density fractions (65/72 and greater than 72) appeared to contain predominantly small resting B cells contaminated by many fewer activated B cells. Functionally, the capacity of fractionated B cells to act as accessory cells for a concanavalin A response or present the antigens chicken ovalbumin (OVA) or OVA-tryptic digest gave similar results, which indicated a striking hierarchy of accessory cell function in the different Percoll fractions. When normalized to the most active low-density fraction (50/60%), the activity of the other fractions were: 60/65 = 78%; 65/72 = 25%; and greater than 72 = 4%. The differences in the functional capacity between the various Percoll fractions did not appear to be due to differences in Ia expression. Although the expression of Ia varied approximately 12-fold within any one fraction, there was little difference in the mean amount of Ia on cells obtained from the various fractions. Kinetic studies showed that activation of B cells with LPS and dextran sulfate resulted in the expression of two stages of functional development. The first stage was an increased efficiency of accessory cell function that was abrogated by irradiation with 4000 rad followed by a second stage, which was characterized by the acquisition of resistance to treatment with 4000 rad. When nonfractionated B cells that had been stimulated with LPS and DexSO4 were sorted on the basis of cell size into a small B cell fraction and a large B cell fraction, only the large B cells were able to present antigen. Taken together, these data suggest that much of the accessory cell function associated with splenic B cells can be accounted for by the relatively small percentage of activated B cells present in the spleen.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗