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Biomedical subjects

S Broder

Publications and source records attributed to S Broder.

At least 217 records · Page 12Linked to original sources
PubMed1980

Normal and malignant T cells in the regulation of inflammation and immunity.

Normal T cells play an important role in the regulation of humoral immune responses by acting as potentiators (helper cells) or inhibitors (suppressor cells) of the process by which B cells mature into immunoglobulin-secreting plasma cells. Certain diseases in which malignant T cells appear to retain an immunoregulatory function are characterized by the propensity of a lymphomatous T-cell population to infiltrate skin. This may lead to an extensive inflammatory syndrome with cutaneous exfoliation. Some cutaneous T-cell lymphomas, as well as some T-cell neoplasms without dermatologic involvement, provide a homogeneous supply of T lymphocytes which have immunoregulatory functions. The availability of such neoplastic T immunoregulators might accelerate the serologic and biochemical analysis of the cellular control of normal immunity in man.

Adult↗
PubMed1980

Fc receptors on human T lymphocytes. V: Effects of colchicine and cytochalasin B on Fc receptor expression.

Previous studies have documented that the interaction of IgG immune complexes with the FcIgG receptor (Fc-IgGR) of human T lymphocytes induces alterations both in the expression of Fc receptors and in the functional capacities of these cells. After IgG immune complex exposure, Fc-IgGR-bearing T lymphocytes lose their Fc-IgGR and generate Fc-IgMR in subsequent culture. This transition phenomenon is mediated via patching and capping of the Fc-IgGR. Since Colchicine and Cytochalasin B have been demonstrated to interfere with capping of other membrane elements by their known effects on cytoskeletal structures, we investigated the effects of these agents on the expression of Fc receptors of human T cells. Neither Colchicine nor Cytochalasin B directly affects Fc-IgGR or Fc-IgMR expression. However, both agents inhibit the loss of Fc-IgGR subsequent to IgG immune complex exposure as well as the development of Fc-IgMR in culture. Immunofluorescent studies illustrate that this inhibition is mediated in part by interference with capping of the Fc-IgGR-immune complex ligand. This study emphasizes the inverse relationship between Fc-IgGR and Fc-IgMR expression on human T lymphocytes.

Animals↗
PubMed1979

Neoplasms of immunoregulatory cells.

This paper provides an overview of neoplasms which appear to be derived from immunoregulatory cells. Normal T cells play a critical role in the regulation of humoral immune responses by acting as potentiators (helper cells) or inhibitors (suppressor cells) of the B cell transition into immunoglobulin-secreting plasma cells. Certain patients with leukemias or lymphomas of T-cell origin may provide a resource for obtaining homogeneous populations of cells which act as either helper cells (e.g., some patients with the Sézary syndrome) or suppressor cells (e.g., some patients with acute or subacute T-leukemia). The clinical and theoretic implications of such immunoregulatory cell neoplasms are discussed.

Agammaglobulinemia↗
PubMed1979

Characterization of lymphoblast Fc receptor expression in acute lymphoblastic leukemia.

Lymphoblasts from 18 patients with untreated acute lymphoblastic leukemia were investigated for the presence of conventional cell surface markers (spontaneous sheep red blood cell rosette formation, complement receptors, and surface immunoglobulin). The expression of Fc receptors for both IgG and IgM was investigated using indicator bovine erythrocytes coated with rabbit anti-BRBC (IgG and LgM fractions). The leukemic cells of all patients in this tudy expressed Fc receptors for both IgC and LgM. In contrast with previous reports, null (non-T non-B) lymphoblasts as well as T lymphoblasts demonstrated Fc-IgG and Fc-IgM receptors. However, these two immunologic subclasses of leukemic cells demonstrated significantly different patterns of Fc receptor distribution. These data suggest that expression of Fc receptors is an early event in cellular differentiation in this lymphoid malignancy.

Adolescent↗
PubMed1979

Current concepts in immunoregulatory T-cell neoplasms.

Normal T cells play a crucial role in the regulation of humoral immune responses by acting as potentiators (helper cells) or inhibitors (suppressor cells) of the B-cell transition into immunoglobulin-secreting plasma cells. Certain patients with leukemias or lymphomas of T-cell origin may provide a resource for obtaining homogeneous populations of cells which act as either helper cells (eg, some but not all patients with Sézary's syndrome) or suppressor cells (eg, some patients with acute of subacute T-cell leukemia). The clinical and theoretic implications of such immunoregulatory cell neoplasms are discussed.

Adult↗
PubMed1978

Characterization of a suppressor-cell leukemia. Evidence for the requirement of an interaction of two T cells in the development of human suppressor effector cells.

To characterize the suppressor activity of neoplastic T cells from a child with acute lymphoblastic leukemia and hypogammaglobulinemia, we applied an in vitro assay that determines the capacity of pokeweed-mitogen-stimulated lymphocytes to mature into immunoglobulin-secreting cells. The geometric mean synthesis by peripheral blood lymphocytes from 12 normal persons was 3200 ng for IgM, 2447 ng for IgG and 1825 for IgA (2 X 10(6) cells per 12 days in culture). The patient's leukemic cells produced no detectable immunoglobulin and depressed the immunoglobulin production of normal lymphocytes by 85 to 100 per cent in co-culture experiments. However, suppression was observed only when co-operating normal T cells were present. Prior irradiation of either the leukemic T cells or the co-operating normal T cells nullified the suppressor effect. Therefore, an interaction between at least two different T-cell subsets may be required for the generation of suppressor effector T cells in man.

Agammaglobulinemia↗
PubMed1978

Reactivity of lupus erythematosus antibodies with leukemic helper T cells.

Immunoabsorbent columns, containing membrane fragments of either leukemic "helper" T cells or B cell lymphoblasts, were used to isolate and study antilymphocyte antibodies from plasmas of 2 patients with systemic lupus erythematosus (SLE). Both plasmas contained IgG which bound to and could be eluted from the "helper" T cell column. These antibodies significantly inhibited normal lymphocyte proliferative responses to microbial and histocompatibility antigens. The findings indicate that these SLE plasmas contain immunoglobulins of the IgG class which react with leukemic "helper" T cells and inhibit normal effector T cell function.

Antibodies↗
PubMed1978

Disorders of suppressor immunoregulatory cells in the pathogenesis of immunodeficiency and autoimmunity.

A series of suppressor cell systems regulate virtually all immunologic processes. Disorders of these systems have been identified in association with a number of diseases. An abnormal number of activated suppressor T-cells have been seen in some patients with common variable hypogammaglobulinemia and in some with selective IgA deficiency. Suppressor T-cells that inhibit immunoglobulin synthesis also develop in an animal model of immunodeficiency, the agammaglobulinemia of the bursectomized bird. Non-T-cell suppressor cells are a pathogenic factor in the humoral immunodeficiency associated with multiple myeloma. At the other end of the spectrum of immunologic response, a reduction in functional activity of suppressor T-cells has been implicated in the pathogenesis of autoimmune diseases. The disorders of suppressor cells that have been shown in immunodeficiency and autoimmunity are important when developing rational strategies for prevention and therapy of these immunologic disorders.

Agammaglobulinemia↗
PubMed1978

Regression of a T-cell lymphoma after administration of antithymocyte globulin.

A patient with Sézary syndrome developed a diffuse undifferentiated lymphoma of T-cell origin. After becoming resistant to multiple chemotherapeutic agents, the patient was treated with antithymocyte globulin. A 75% reduction in adenopathy and complete resolution of skin erythema was observed during an 8-day period. In addition the percent of circulating T cells and the ability of those cells to respond to phytohemagglutinin and concanavalin A were reduced after antithymocyte globulin therapy. The patient died of an intracerebral hemorrhage secondary to profound thrombocytopenia. The study suggests that tumor lysis may be achieved by passive antibody therapy in certain advanced lymphomas.

Antilymphocyte Serum↗