transforming-growth-factor-beta and Thymoma

Thymoma is a rare characterized by a unique association with autoimmune diseases, especially myasthenia gravis (MG). However, little is known about the molecular characteristics of MG-associated thymoma individuals. We aim to examine the influences of MG on thymoma by analyzing multiomics data. A total of 105 samples with thymoma was analyzed from TCGA and these samples were divided into subgroups with MG (MGT) or without MG (MGF) according to clinical information. We then characterized the differential gene expression, pathway activity, somatic mutation frequency, and likelihood of responding to chemotherapies and immunotherapies of the two identified subgroups. MGT subgroup was characterized by elevated inflammatory responses and metabolically related pathways, whereas the MGF subgroup was predicted to be more sensitive to chemotherapy and presented with mesenchymal characteristics. More copy number amplifications and deletions were observed in MGT, whereas GTF2I mutations occur at significantly higher frequencies in MGF. Two molecular subtypes were further identified within MGF samples by unsupervised clustering where one subtype was enriched in TGF-β and WNT pathways with higher sensitivity to relevant targeted drugs but hardly respond to immunotherapy. For another subtype, a higher recurrence rate of thymoma and more likelihood of responding to immunotherapy were observed. Our findings presented a comprehensive molecular characterization of thymoma patients given the status of MG, and provided potential strategies to help individualized management and treatment.

Topics: Aged; Disease-Free Survival; DNA Copy Number Variations; Drug Therapy; Female; Gene Expression Regulation, Neoplastic; Humans; Immunotherapy; Male; Middle Aged; Myasthenia Gravis; Neoplasm Proteins; Precision Medicine; Thymoma; Transcription Factors, TFII; Transforming Growth Factor beta; Wnt Signaling Pathway

Tranilast (N-[3,4-dimethoxycinnamonyl]-anthranilic acid) is a drug of low toxicity that is orally administered, and has been used clinically in Japan as an antiallergic and antifibrotic agent. Its antifibrotic effect is thought to depend on the inhibition of transforming growth factor-beta (TGF-beta). It has also been shown to exert antitumor effects, but its mode of action is unclear. Here, we explored the antitumor effects of tranilast in vitro and in vivo. Tranilast inhibited the proliferation of several tumor cell lines including mouse mammary carcinoma (4T1), rat mammary carcinoma stem cell (LA7), and human breast carcinoma (MDA-MB-231 and MCF-7). Tranilast blocked cell-cycle progression in vitro. In the highly metastatic 4T1 cell line, tranilast inhibited phospho-Smad2 generation, consistent with a blockade of TGF-beta signaling. It also inhibited the activation of MAP kinases (extracellularly regulated kinase 1 and 2 and JNK), which have been linked to TGF-beta-dependent epithelial-to-mesenchymal transition and, indeed, it blocked epithelial-to-mesenchymal transition. Although tranilast only partially inhibited TGF-beta production by 4T1 tumor cells, it potently inhibited the production of TGF-beta, interferon-gamma, IL-6, IL-10, and IL-17 by lymphoid cells, suggesting a general anti-inflammatory activity. In vivo, female BALB/c mice were inoculated with syngeneic 4T1 cells in mammary fat pads and treated with tranilast by gavage. Tranilast reduced (>50%) the growth of the primary tumor. However, its effects on metastasis were more striking, with more than 90% reduction of metastases in the lungs and no metastasis in the liver. Thus, tranilast has potential activity as an antimetastatic agent in breast cancer.

Topics: Animals; Antineoplastic Agents; Carcinoma; Cell Line, Tumor; Cell Transdifferentiation; Drug Screening Assays, Antitumor; Enzyme Activation; Female; Humans; Liver Neoplasms; Lung Neoplasms; Lymphoma; Mammary Neoplasms, Experimental; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mitogen-Activated Protein Kinases; Neoplasm Proteins; Organ Specificity; ortho-Aminobenzoates; Rats; Rats, Sprague-Dawley; Smad2 Protein; Species Specificity; Thymoma; Thymus Neoplasms; Transforming Growth Factor beta

Tumor-infiltrating stroma cells (TISC) as well as tumors themselves are thought to be involved in tumor-related immunosuppression, which is one of the critical mechanisms of tumor escape from immune surveillance. However, preparation of TISC is difficult because of the small proportion of TISC in established tumors. Thus, the cells thought to be involved in tumor-related immunosuppression are generally prepared from spleens or draining lymph nodes in tumor-bearing mice. In this study, we developed a method for directly preparing TISC from established tumors in order to analyze their function. Using green fluorescent protein (GFP) transgenic (Tg) mice and C57BL/6 mice transplanted with bone marrow (BM) cells of GFPTg mice, we detected three subpopulations of TISC: one is compatible with immature myeloid cells (ImC) derived from BM and the two other subpopulations, CD11b(+) cells and CD11b(-) cells, do not originate from BM. The TISC including these subpopulations but not each subpopulation independently after culturing with tumors in the presence of GM-CSF could suppress T cell proliferation induced by anti-CD3. In our system, tumors did not inhibit T cell responses directly, but unknown factors from tumors affected immunosuppression by TISC.

Topics: Animals; Bone Marrow Cells; Bone Marrow Transplantation; CD11b Antigen; Enzyme-Linked Immunosorbent Assay; Flow Cytometry; Immune Tolerance; Immunologic Surveillance; Interleukin-10; Lymphocyte Activation; Mice; Mice, Inbred C57BL; Mice, Transgenic; Neoplasm Transplantation; Stromal Cells; T-Lymphocytes; Thy-1 Antigens; Thymoma; Transforming Growth Factor beta; Transplantation Chimera; Tumor Escape

During thymic T cell development, immature CD4+CD8+ double-positive (DP) thymocytes develop either into CD4+CD8- Th cells or CD4-CD8+ CTLs. Differentially expressed primary factors inducing the fate of these cell types are still poorly described. The transcription factor Runx3/AML-2 Runx, runt [corrected] dominant factor; AML, acute myeloid leukemia is expressed specifically during the development of CD8 single-positive (SP) thymocytes, where it silences CD4 expression. Deletion of murine Runx3 results in a reduction of CD8 SP T cells and concomitant accumulation of CD4+CD8+ T cells, which cannot down-regulate CD4 expression in the thymus and periphery. In this study we have investigated the role of Runx3 during thymocyte development and CD4 silencing and have identified integrin alpha(E)/CD103 on CD8 SP T cells as a new potential target gene of Runx3. We demonstrate that Runx3 is necessary not only to repress CD4, but also to induce CD103 expression during development of CD8 SP T cells. In addition, transgenic overexpression of Runx3 reduced CD4 expression during development of DP thymocytes, leading to a reduced number of CD4 SP thymocytes and an increased number of CD8 SP thymocytes. This reversal is not caused by redirection of specific MHC class II-restricted cells to the CD8 lineage. Overexpression of Runx3 also up-regulated CD103 expression on a subpopulation of CD4 SP T cells with characteristics of regulatory T cells. Thus, Runx3 is a main regulator of CD4 silencing and CD103 induction and thus contributes to the phenotype of CD8 SP T cells during thymocyte development.

Topics: Amino Acid Sequence; Animals; Antigens, CD; CD4 Antigens; CD4-CD8 Ratio; CD4-Positive T-Lymphocytes; CD8 Antigens; CD8-Positive T-Lymphocytes; Cell Differentiation; Cell Line, Tumor; Cell Lineage; Core Binding Factor Alpha 3 Subunit; Crosses, Genetic; DNA-Binding Proteins; Down-Regulation; Gene Silencing; Growth Inhibitors; Histocompatibility Antigens Class II; Integrin alpha Chains; Killer Cells, Natural; Lymphopenia; Mice; Mice, Inbred C3H; Mice, Inbred C57BL; Mice, Knockout; Mice, Transgenic; Molecular Sequence Data; Thymoma; Thymus Gland; Transcription Factors; Transforming Growth Factor beta

When a cancer escapes the growth-inhibitory effects of TGF-beta secreted by cancer cells themselves or by cells in the local stroma, a further adverse outcome for the host is the associated TGF-beta-induced suppression of anticancer T cell immunity. In addition to the previously described dampening of T cell activation and proliferation, TGF-beta markedly and directly suppresses the transcription of genes encoding multiple key proteins of the "cytotoxic program" of CD8+ CTL, such as perforin and granzymes, cytotoxins that act through the granule exocytosis pathway. The findings described below suggest that TGF-beta and its signaling pathways will be major targets for novel cancer therapeutics.

Topics: Activating Transcription Factors; Animals; Antineoplastic Agents; Blood Proteins; Cell Line, Tumor; Cell Proliferation; Cytotoxicity, Immunologic; Disease Progression; Granzymes; Membrane Glycoproteins; Mice; Models, Biological; Perforin; Pore Forming Cytotoxic Proteins; Serine Endopeptidases; Signal Transduction; T-Lymphocytes, Cytotoxic; Thymoma; Transforming Growth Factor beta; Tumor Escape

Topics: Antigens, CD; Antigens, Differentiation, B-Lymphocyte; Cell Adhesion Molecules; Child; DNA-Binding Proteins; Humans; Hyperplasia; Immunohistochemistry; Keratins; Lectins; Myasthenia Gravis; Nerve Tissue Proteins; Nuclear Proteins; Receptors, Steroid; Receptors, Thyroid Hormone; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Sialic Acid Binding Ig-like Lectin 2; Thymoma; Thymus Gland; Transforming Growth Factor beta; Transforming Growth Factor beta1

Topics: Animals; CD4-Positive T-Lymphocytes; CD8-Positive T-Lymphocytes; Immune Tolerance; Melanoma, Experimental; Mice; Mice, Transgenic; Neoplasm Transplantation; Protein Serine-Threonine Kinases; Receptor, Transforming Growth Factor-beta Type II; Receptors, Transforming Growth Factor beta; Signal Transduction; Thymoma; Thymus Neoplasms; Transforming Growth Factor beta; Tumor Cells, Cultured

Thymoma is the most common tumor of the anterior-superior mediastinum. We have identified a line of transgenic mice which spontaneously and heritably develop thymomas at a very high penetrance. The available data suggest that thymoma formation in these mice results as a consequence of transgene insertional mutagenesis. Immune histologic analyses indicate that the thymomas are of epithelial cell origin. Survival studies indicate that tumor progression is more aggressive in females as compared to males (73.9 vs 41.7% mortality at 20 weeks of age, respectively). Fluorescent in situ hybridizations have localized the transgene integration site to the F2-G region of mouse chromosome 2. Translocation encompassing the syntenic region in humans has been implicated in lympho-epithelial thymoma. These animals may constitute a useful resource for the identification of gene(s) which participate in thymoma progression, as well as a model system for screening anti-thymoma therapeutic agents.

Topics: Animals; Female; Major Histocompatibility Complex; Male; Mice; Mice, Inbred C3H; Mice, Transgenic; Mutation; Thymoma; Thymus Neoplasms; Transforming Growth Factor beta

In the present study we investigated the interleukin (IL)-1beta and transforming growth factor-beta1 (TGF-beta1)-mediated proliferation, and production of IL-2 and TGF-beta, in the murine T-cell line, EL4.NOB-1. This cell line is resistant to TGF-beta concerning growth arrest but not autoinduction or suppression of IL-1-induced IL-2 production. When cocultured with IL-1beta, TGF-beta showed growth-promoting activity that could be antagonized by adding the phosphatidyl choline-dependent phospholipase C (PC-PLC) inhibitor, D609. Using specific enzyme inhibitors of protein kinases (PK) C and A, mitogen-activated protein kinase (MAPK), phospholipase A2 (PLA2), phosphatidylinositol-dependent (PI)-PLC and PC-PLC, we showed that IL-1beta-induced IL-2 synthesis was dependent on all investigated kinases and phospholipases, except PC-PLC. TGF-beta1 was able to inhibit IL-2 synthesis by the activation of PKA and MAPK. The same kinases are involved in TGF-beta autoinduction that is accompanied by a secretion of the active but not the latent growth factor and is antagonized by IL-1beta. Addition of the PI-PLC inhibitor, ET 18OCH3, or the PLA2 inhibitor (quinacrine) alone, resulted in secretion of latent TGF-beta and, in the case of ET 18OCH3, active TGF-beta. These data implicate a role for PI-PLC and PLA2 in the control of latency and secretion. Analysis of specific tyrosine activity and c-Fos expression showed synergistic but no antagonistic effects. These events are therefore not involved in IL- and TGF-beta-regulated IL-2 and TGF-beta production, but might participate in IL-1/TGF-beta-induced growth promotion.

Topics: Animals; Enzyme Activation; Enzyme Inhibitors; Interleukin-1; Interleukin-2; Lymphocyte Activation; Phytohemagglutinins; Protein-Tyrosine Kinases; Proto-Oncogene Proteins c-fos; Signal Transduction; Thymoma; Transforming Growth Factor beta; Tumor Cells, Cultured

Many types of tumor cells overexpress transforming growth factor beta (TGF-beta), which is believed to promote tumor progression. We hypothesized that overexpression of the extracellular region of the type II TGF-beta receptor (soluble TbetaRII) would compete for or block TGF-beta binding to TbetaRs on immune cells, preventing TGF-beta-mediated immunosuppression and consequently resulting in the eradication of tumor cells. We tested this in the mouse thymoma cell line EL4, which has been reported to suppress cellular immunity by secreting a large amount of TGF-beta. Transduction of EL4 with recombinant retrovirus encoding soluble TbetaRII resulted in the secretion of heterogeneously glycosylated, 25 to 35 kDa truncated TbetaRII. Inoculation of 1 x 10(4) to 5 x 10(4) soluble TbetaRII-modified EL4 cells (EL4/Ts, EL4 cells transduced with recombinant retrovirus encoding soluble TbetaRII and neomycin resistance gene) s.c. to mice showed reduced tumorigenicity, as indicated by lower overall tumor incidence (7%, 1 of 14; P < 0.001) compared with unmodified EL4 (100%, 9 of 9) or vector-modified EL4 cells (EL4/neo, EL4 cells transduced with recombinant retrovirus encoding neomycin resistance gene; 100%, 4 of 4). Administration of mitomycin C-treated EL4/Ts cells (1 x 10(6)) after EL4 inoculation (1 x 10(4)) reduced tumor incidence from 100% (5 of 5 in mice inoculated with mitomycin C-treated EL4/neo) to 40% (4 of 10, P < 0.05), indicating that supply of soluble TbetaRII could actually block TGF-beta-mediated tumorigenesis. In vitro tumor cytotoxicity assays revealed 3-5-fold higher cytotoxic activity with lymphocytes from EL4/Ts-bearing mice compared with those from EL4- or EL4/neo-bearing mice, indicating that the observed tumor rejection was mediated by restoration of the tumor-specific cellular immunity. These data suggest that expression of soluble TbetaRII is an effective strategy for treating highly progressive tumors secreting TGF-beta.

Topics: Animals; Disease Progression; Immunosuppression Therapy; Mice; Mice, Inbred C57BL; Mutagenesis; Neoplasm Transplantation; Receptors, Transforming Growth Factor beta; Thymoma; Thymus Neoplasms; Transforming Growth Factor beta; Tumor Cells, Cultured

Topics: Adolescent; Adult; Aged; Cells, Cultured; Child; Female; Humans; Hyperplasia; Interferon-gamma; Interleukin-4; Leukocytes, Mononuclear; Male; Middle Aged; Myasthenia Gravis; Reference Values; Thymoma; Thymus Gland; Thymus Neoplasms; Transforming Growth Factor beta

To determine whether changes in the plasma Transforming Growth Factor beta1 (TGF beta1) concentration during radiotherapy could identify patients at risk for developing symptomatic radiation pneumonitis.. Thirty-six patients who received radiation therapy with curative intent for lung cancer (n = 31), Hodgkin's disease (n = 4), or thymoma (n = 1) were evaluated prospectively. All patients had serial plasma TGF beta1 measurements obtained before, during, and after treatment. Plasma TGF beta1 was quantified using an enzyme-linked immunosorbent assay. Pneumonitis was defined clinically. Plasma TGF beta1 levels were considered to have normalized if the following occurred: the last on-treatment TGF beta1 level was both <7.5 ng/ml and lower than the pretreatment level.. Thirteen of these 36 patients developed pneumonitis. Significant changes in plasma TGF beta1 levels during treatment were seen only in the subset of patients whose TGF beta1 levels were >7.5 ng/ml at baseline (n = 22). Failure of plasma TGF beta1 to normalize by the end of treatment, as defined above, much more accurately identified patients at risk for symptomatic pneumonitis if their baseline TGF beta1 was >7.5 ng/ml than if it was <7.5 ng/ml.. Changes in plasma TGF beta1 levels during radiotherapy appears to be a useful means by which to identify patients at risk for the development of symptomatic radiation pneumonitis, particularly in the subset of patients whose pretreatment TGF beta1 levels are >7.5 ng/ml.

Topics: Biomarkers; Hodgkin Disease; Humans; Lung Neoplasms; Prospective Studies; Radiation Pneumonitis; Sensitivity and Specificity; Thymoma; Transforming Growth Factor beta

In previous reports, we showed that tumor-derived TGF-beta induced overproduction of IL-10, and these suppressive cytokines caused macrophage suppression in EL4-bearing mice. Proliferation of T cells from EL-4, but not IL-2, whereas T cells from normal mice were responsive to IL-2. A balance between Th1- and Th2-type cytokine production in EL4-T in response to anti-CD3 Ab or phorbor myristate acetate plus A23187 shifted toward the Th2 dominant pattern. The prevention of TGF-beta and IL-10 activates in vivo by administration of anti-IL-10 Ab (anti-IL-10) or anti TGF-beta Ab (anti-TGF-beta) resulted in the reduction in EL4-T of both IL-4 dependent proliferation and Th2-dominant cytokine production induced by anti-CD-3 stimulation. In addition, the anti-TGF-beta treatment resulted in complete restoration in EL4-T of suppressed IL-2 responsiveness, IL-2R expression, and Th1-type cytokine production, whereas the anti-IL-10 treatment produced partial recovery. These results lead us to conclude that TGF-beta drives the shift in the Th1/Th2 balance toward Th2 via IL-10-mediated development of the Th2 responses and via inhibition of the Th1-type responses directly in EL4-bearing mice.

Topics: Animals; Antibodies, Monoclonal; Cytokines; Female; Interleukin-10; Interleukin-4; Lymphocyte Activation; Mice; Mice, Inbred C57BL; Receptors, Interleukin-2; Th2 Cells; Thymoma; Transforming Growth Factor beta; Tumor Cells, Cultured

RRR-alpha-tocopheryl succinate (VES) was studied for effects on murine EL-4 cell proliferation and production of interleukin-2 (IL-2) and transforming growth factor-beta (TGF-beta). VES was biphasic in its actions: 0.1 microgram/ml enhanced EL-4 cell proliferation, whereas 10-20 microgram/ml inhibited cellular proliferation. Cell-conditioned media (CM) from EL-4 cells treated with 0.2 ng/ml phorbol myristate acetate (PMA) + 0.1 microgram/ml VES contained increased amounts of IL-2, as determined by the murine cytotoxic T cell IL-2-dependent CTLL-2 bioassay. VES at 0.1 microgram/ml or 0.1 microgram/ml VES + 0.2 ng/ml PMA induced the expression of IL-2 mRNA by EL-4 cells three to nine hours after treatment. CM from EL-4 cells treated with VES at 10-20 microgram/ml exhibited potent antiproliferative activity when tested in the TGF-beta-responsive mink lung cell (Mv1Lu) bioassay and showed reduced inhibitory effects when tested on TGF-beta receptor-negative mink lung (DRA-27) cells. CM from control-treated EL-4 cells exhibited no antiproliferative activity. The VES-induced antiproliferative activity was characterized as TGF-beta by neutralization analyses and immunoprecipitation of metabolically labeled proteins with TGF-beta-specific reagents. VES treatment of EL-4 cells had no effect on TGF-beta 1 mRNA expression while downregulating TGF-beta 3 mRNA expression. In summary, these studies showed that 0.1 microgram/ml VES enhanced cellular proliferation, in part, via increased IL-2 production, whereas 10-20 micrograms/ml VES inhibited cellular proliferation, in part, via the secretion of biologically active TGF-beta.

Topics: Animals; Cell Division; Culture Media, Conditioned; Cytokines; Gene Expression; Interleukin-2; Mice; RNA, Messenger; Tetradecanoylphorbol Acetate; Thymoma; Thymus Neoplasms; Tocopherols; Transforming Growth Factor beta; Tumor Cells, Cultured; Vitamin E

In the present study, we demonstrate that TGF-beta is capable of enhancing macrophage ability to produce IL-10 in normal and EL4 tumor-bearing mice. We found the increase in IL-10 in ascitic fluid and IL-10 mRNA expression in macrophages in parallel with the TGF-beta level and tumor progression. The macrophage production of IL-10 in the tumor-bearing mice was significantly enhanced without LPS stimulation in vitro, compared with normal controls. To clarify the mechanism wherein increased IL-10 production was induced, anti-TGF-beta or anti-IL-10 Abs were administered to EL4-bearing mice. Administration of anti-TGF-beta Ab led to a reduction in the IL-10 contents in ascitic fluid of tumor-bearing mice; however, anti-IL-10 Ab administration did not prevent the increase in TGF-beta contents. Enhanced IL-10 production and mRNA expression of macrophages from the tumor-bearing mice were also reduced by anti-TGF-beta Ab administration. Both anti-TGF-beta and anti-IL-10 Ab administration restored the TNF-alpha production by macrophages in EL4-bearing mice. In normal macrophages, in vitro pretreatment with TGF-beta 1 potentiated IL-10 production, and when natural TGF-beta 1 was administered to normal mice, the recovered peritoneal macrophages showed enhanced IL-10 production. Based on the above findings it can be concluded that TGF-beta enhances macrophage ability to produce IL-10, which sheds a new light on the role of TGF-beta in the immune system.

Topics: Animals; Base Sequence; Cells, Cultured; Female; Interleukin-10; Macrophages, Peritoneal; Mice; Mice, Inbred C57BL; Molecular Sequence Data; RNA, Messenger; Thymoma; Transforming Growth Factor beta

An experimental therapy for improvement of macrophage dysfunction caused by transforming growth factor-beta (TGF-beta) was tried in EL4 tumor-bearing mice. TGF-beta was detected in cell-free ascitic fluid from EL4-bearers, but not in that from normal mice, by western blot analysis. The ascites also showed growth-suppressive activity against Mv1Lu cells, and the suppressive activity was potentiated by transient acidification. To investigate whether the functions of peritoneal macrophages were suppressed in EL4-bearers, the abilities to produce nitric oxide and tumor necrosis factor-alpha (TNF-alpha) upon lipopolysaccharide (LPS) stimulation were measured. Both abilities of macrophages in EL4-bearing mice were suppressed remarkably on day 9, and decreased further by day 14, compared with non-tumor-bearing controls. TGF-beta activity was abrogated by administration of anti-TGF-beta antibody to EL4-bearing mice. While a large amount of TGF-beta was detected in ascitic fluid from control EL4-bearers, little TGF-beta was detectable in ascites from EL4-bearers given anti-TGF-beta antibody. Furthermore, while control macrophages exhibited little or no production of nitric oxide and TNF-alpha on LPS stimulation in vitro, macrophages from EL4-bearers administered with anti-TGF-beta antibody showed the same ability as normal macrophages. These results clearly indicate that TGF-beta contributes to macrophage dysfunction and that the administration of specific antibody for TGF-beta reverses macrophage dysfunction in EL4-bearing hosts.

Topics: Animals; Antibodies; Blotting, Western; Female; Immune Tolerance; Macrophages; Mice; Mice, Inbred C57BL; Nitric Oxide; Thymoma; Transforming Growth Factor beta; Tumor Cells, Cultured; Tumor Necrosis Factor-alpha

The effect of IL-4 and transforming growth factor-beta (TGF-beta) on immunoglobulin secretion in vitro by peripheral blood mononuclear cells (PBMC) or purified B cells activated with murine EL4 thymoma cells and phorbol myristate acetate (PMA) was investigated. As previously reported, IL-4 induced IgE and IgG4 secretion by B cells in PBMC preparations and B cells activated with EL4 cells and PMA. However, when B cells, either in PBMC preparations or purified and activated with EL4 cells and PMA, spontaneously secreted large quantities of immunoglobulin, IL-4 suppressed the immunoglobulin secretion of all isotypes. IL-4 also suppressed the IgE secretion by B cells from an atopic dermatitis patient. This suppressive effect was not reversed by adding IL-2 or interferon-gamma (IFN-gamma) to the cultures. We also showed that TGF-beta suppressed the immunoglobulin secretion by purified B cells activated by EL4 cells and PMA. To investigate whether IL-4 or TGF-beta suppressed immunoglobulin secretion by in vivo 'switched' and isotype-committed B cells, sIgD- B cells were isolated, activated with EL4 cells and PMA and cultured with IL-4 or TGF-beta. Such activated B cells secreted large quantities of IgG1, IgG2, IgG3, IgA1, IgA2 and IgM, and IL-4 and TGF-beta suppressed all these isotypes by greater than 80%. The data demonstrated that IL-4 and TGF-beta suppress immunoglobulin secretion in vitro by in vivo isotype-committed sIgD- B cells, suggesting that these lymphokines may play a down-regulatory role on differentiated isotype-committed B cells in an isotype-unrestricted manner. The data also showed that IL-4 and TGF-beta acted directly on isolated B cells.

Topics: B-Lymphocytes; Humans; Immunoglobulin D; Immunoglobulin Isotypes; Immunoglobulins; Interferon-gamma; Interleukin-2; Interleukin-4; Receptors, Antigen, B-Cell; Tetradecanoylphorbol Acetate; Thymoma; Transforming Growth Factor beta

The effect of human colostrum on T cell immune function was investigated. Colostrum inhibited the proliferation of human T cells activated by allogeneic, concanavalin A (Con A) or phytohaemagglutinin (PHA) stimulation. Colostrum also inhibited the production of IL-2 by Con A-activated human peripheral blood T cells and by Con A-activated Jurkat cells, a human T lymphoma line. Similarly, human colostrum inhibited the production of IL-2 by EL4 cells, a murine thymoma line, when stimulated with phorbol myristate acetate. The inhibitory activity was not cytotoxic and could not be neutralized by antibody to transforming human growth factor beta.

Topics: Cell Survival; Colostrum; Concanavalin A; Dose-Response Relationship, Drug; Humans; Interleukin-2; Lectins; Lymphocyte Activation; Lymphocyte Culture Test, Mixed; Lymphoma, T-Cell; Phytohemagglutinins; T-Lymphocytes; Tetradecanoylphorbol Acetate; Thymoma; Thymus Neoplasms; Transforming Growth Factor beta

Transforming growth factor type beta 1 (TGB-beta 1) belongs to a family of polypeptides with regulatory effects on growth and differentiation of a variety of cell types. TGB-beta 1 plays an important role in regulation of immune response by acting as a negative control signal for T cell proliferation through still unknown mechanisms. In this study we have analysed the effects of TGB-beta 1 on EL 4-6.1, a variant of the murine EL 4 thymoma, which can be induced by phorbol 12-myristate 13-acetate (PMA) and/or interleukin 1 (IL-1) to secrete interleukin 2 (IL-2) and express IL-2 receptors (IL-2R). Using this defined model system, we show that TGB-beta 1 simultaneously down-regulates IL-2 expression and up-regulates the number of both high and low affinity IL-2R. These changes correlate with changes at the mRNA level, suggesting an effect at the pre-translational level. The specificity of both TGF-beta 1 effects was demonstrated using a neutralizing antiserum to TGF-beta 1. Our data also suggest that TGF-beta 1 does not interfere with early activation signals of PMA and/or IL-1. This model might be useful for elucidating the complex role of TGF-beta 1 in the regulation of T cell responses.

Topics: Animals; Down-Regulation; Gene Expression; Interleukin-1; Interleukin-2; Mice; Receptors, Interleukin-2; RNA, Messenger; T-Lymphocytes; Tetradecanoylphorbol Acetate; Thymoma; Thymus Neoplasms; Transforming Growth Factor beta; Up-Regulation

In order to further characterize the action of transforming growth factor beta (TGF-beta) on lymphoid cells, we investigated the effects of porcine TGF-beta 1 and -2 on the IL-1 sensitive EL4/6.1 thymoma cell line. The proliferation of EL4/6.1 thymoma cells was inhibited by TGF-beta 1 and TGF-beta 2 (1 ng/ml) to a similar degree, the population doubling time was increased by 50-60%, total inhibition was not achieved. This decrease of proliferation was associated with an increase of the number of cells in the G0/G1 compartment of the cell cycle. TGF-beta-mediated inhibition could not be overcome by adding exogenous rIL-1 nor was the binding capacity for IL-1 reduced. In addition, TGF-beta did not interfere with the induction of IL-2 receptors by a combination of Ionomycin+PMA+IL-1. The data suggest that TGF-beta mediated inhibition of thymocyte/lymphocyte proliferation is not associated with an inhibition of the expression or the induction of expression of IL-2 or IL-1 receptors.

Topics: Animals; Cell Division; Gene Expression Regulation, Neoplastic; Interleukin-1; Ionomycin; Mice; Receptors, Immunologic; Receptors, Interleukin-1; Receptors, Interleukin-2; Recombinant Proteins; Tetradecanoylphorbol Acetate; Thymoma; Thymus Neoplasms; Transforming Growth Factor beta; Tumor Cells, Cultured