David Blumenthal

Washington University in St. Louis, Saint Louis, MO, United States

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Publications (4)20.91 Total impact

  • Source
    Proceedings of the National Academy of Sciences 08/1996; 93(15):8154. · 9.81 Impact Factor
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    ABSTRACT: Systemic lupus erythematosus (SLE) is a disease characterized by the prolonged production of high-affinity autoantibodies resulting in direct and immune complex-mediated tissue damage. Because autoantibody responses occur over several years, memory B cells are likely to be involved. Interleukin-14 (IL-14) is a cytokine implicated in the generation and maintenance of normal memory B cells. Many of the actions of IL-14, including inhibition of antibody synthesis and upregulation of IL-14 receptors (IL-14R), are dependent on the formation of prostaglandin E (PGE) and subsequently cAMP. We observed that IL-14 induces phospholipase A(2) (PLA(2))-dependent release of arachidonic acid from phosphatidylcholine and phosphatidylinositol. Production of PGE is blocked by the PLA(2) inhibitor bromophenacyl bromide. Exogenous PGE (misoprostol) induces similar inhibition of antibody synthesis and increases in IL-14R as IL-14. Lymphocytes from patients with inactive SLE were noted to spontaneously produce PGE. Lymphocytes from normal donors produced PGE only after Sac-activation and IL-14 stimulation. Peripheral B and T lymphocytes from SLE patients, but not normal donors, spontaneously produced IL-14. Increased numbers of peripheral B lymphocytes from patients with inactive SLE expressed IL-14R, when compared to normal donors. Thus, increased production of IL-14 and PGE in SLE may result in expansion of a memory B-cell population capable of long-term autoantibody production. Further study will be necessary to confirm these preliminary findings and to examine in greater depth the regulation of PGE and IL-14 in SLE patients and normal donors.
    American journal of therapeutics 01/1996; 2(12):933-942. · 1.29 Impact Factor
  • American Journal of Therapeutics - AM J THER. 01/1995; 2(12).
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    ABSTRACT: Proliferation is necessary for many of the phenotypic changes that occur during B-cell maturation. Further differentiation of mature B cells into plasma cells or memory B cells requires additional rounds of proliferation. In this manuscript, we describe a cDNA for a human B-cell growth factor we call high-molecular-weight B-cell growth factor (HMW-BCGF). Purified HMW-BCGF has been shown to induce B-cell proliferation, inhibit immunoglobulin secretion, and selectively expand certain B-cell subpopulations. Studies using antibodies to HMW-BCGF and its receptor have suggested that HMW-BCGF, while produced by T cells and some malignant B cells, acts predominantly on normal and malignant B cells. The HMW-BCGF cDNA was identified by expression cloning using a monoclonal antibody and polyclonal antisera to HMW-BCGF. Protein produced from the cDNA induced B-cell proliferation, inhibited immunoglobulin secretion, and was recognized in immunoblots by anti-HMW-BCGF antibodies. The amino acid sequence of HMW-BCGF deduced from the cDNA predicts a secreted protein of 53 kDa with three potential N-linked glycosylation sites. The identification of this cDNA will allow further studies examining physiologic roles of this cytokine. We propose to call it interleukin 14.
    Proceedings of the National Academy of Sciences 08/1993; 90(13):6330-4. · 9.81 Impact Factor