PubMed Health⌕ Search

Biomedical subjects

E M Palmer

Publications and source records attributed to E M Palmer.

9 recordsLinked to original sources
PubMed1997

Human T helper cell differentiation is regulated by the combined action of cytokines and accessory cell-dependent costimulatory signals.

We have developed an in vitro differentiation model for human Th cells to study the role of cytokines and accessory cell-dependent costimulatory signals in this process. Peripheral blood-derived CD4+ "naive" (CD45RA+ RO-) T cells were stimulated in weekly intervals with immobilized anti-CD3 mAb, accessory cells, and exogenous cytokines, and were analyzed for cytokine secretion pattern. With the B cell line JY (B7-1+ B7-2+), as source of accessory cells, we could generate distinct Th subsets. Coculture with the combination of recombinant human (rh) IL-1beta and rhIL-6 gave rise to Th0-like cells, which secreted low levels of IFN-gamma and IL-5. The addition of rhIL-12 led to the generation of Th1-like cells, which secreted high levels of IL-2, IFN-gamma, TNF-alpha, and upon multiple stimulations, significant levels of IL-10. The presence of rhIL-4 induced Th2-like cells that secreted high levels of IL-5 and IL-13, but undetectable levels of IL-4. Only after stimulation with phorbol ester and calcium ionophore could these Th2-like cells be induced to secrete significant levels of IL-4, indicating distinct stimulatory requirements for the induction of IL-5 and IL-13 compared with IL-4. The B7-1-negative monocytic cell line U937 could only provide accessory cell-dependent costimulatory signals for the generation of Th1-like cells, while B7-1-transfected U937 cells acquired the capacity to provide costimulation for the generation of Th2-like cells. These results indicate a differential dependence on CD28-mediated costimulation for the generation of human Th1-like and Th2-like cells.

Anti-Inflammatory Agents↗
PubMed1997

Evaluating the role of Th0 and Th1 clones in autoimmune thyroid disease by use of Hu-SCID chimeras.

To study the role of Th0 and Th1 cells in autoimmune thyroid disease, thyroid tissues from patients with Graves' disease (GD), Hashimoto's thyroiditis (HT), and colloid nodular disease were xenografted into SCID mice, followed by ip injection of peripheral blood mononuclear cells (PBMC), T cell lines, and T cell clones (TCC). The antigen-specific TCC reactive to TSH receptor (TSH-R), thyroid peroxidase (TPO), or thyroglobulin (Tg), and their respective peptides, were classified into Th0 (secreting IL-4 and/or IL-5 and IFN-gamma) and Th1 (secreting IFN-gamma) according to their cytokine profile. Engraftment of autologous or HLA-matched allogeneic CD4+ thyroid-specific clones with Th0 or Th1 phenotypes induced the production of total IgG and thyroid-specific autoantibodies by B cells present in xenografted thyroid tissues. TSH-R-specific clones mainly enhanced thyroid-stimulating antibodies (TSAb) production, while clones reactive to TPO and Tg increased the synthesis of TPO and Tg autoantibodies. Total IgG production, but not TSAb, was also stimulated by PBMC and TSH-R lines. TSAb correlated with the viability and hyperplasia of thyroid follicles, but not with the serum T3 levels, which were normal. Thyroid tissue viability was maintained or increased by antigen-specific Th0 clones, and decreased by Th1 clones reactive to TSH-R or TPO. Thyroid lymphocytic infiltration was variable; however, Th0 and Th1 clones from HT patients caused high degree of lymphocytic infiltration compared to the control groups. These results demonstrate for the first time that T cells clones reactive to specific epitopes of TSH-R, TPO, or Tg can generate antibody-mediated and/or cell-mediated responses in the xenografted thyroid tissue microenvironment. Such effects depend on clonal specificity, HLA class II restriction, and cytokine profile of the clone. Th0 clones reactive to TSH-R stimulate both total IgG production and TSAb in SCID mice engrafted with thyroid tissue from GD patients. Th0 and Th1 clones specific for TPO and Tg also function as helper T cells, stimulating total IgG synthesis and autoantibodies against TPO and Tg. Th1 clones may also cause tissue destruction in GD and HT.

Adolescent↗
PubMed1997

Thyrotropin-receptor and thyroid peroxidase-specific T cell clones and their cytokine profile in autoimmune thyroid disease.

We studied the cytokine profile and the immune responses to thyroid antigens of specific T cell clones (TCC) isolated from patients with Hashimoto's thyroiditis (HT) and Graves' disease (GD). Antigen-specific TCC were reactive to thyroid peroxidase (TPO), thyroglobulin (Tg) or human recombinant TSH-receptor extracellular domain (TSH-R), and/or their respective peptides. Of the 43 clones derived from HT patients, 65% were reactive to TPO, and 59% of the 32 clones derived from GD patients were reactive to TSH-R. TPO epitopes 100-119 and 625-644 were recognized by 75% of HT-derived clones, whereas TSH-R epitopes 158-176, 207-222, and 343-362/357-376 were recognized by 85% of GD-derived TCC. The TCC were classified according to their cytokine profile into T helper cell (Th)0 [secreting interleukin (IL)-4, IL-5, interferon (IFN)-gamma], Th1 (secreting IFN-gamma) and Th2 (secreting IL-4 and/or IL-5). Tumor necrosis factor-beta and IL-10 were produced by all subsets. The specific TCC were predominantly Th1-like cells in HT, and were Th0- and Th1-like cells in GD. Fifty three percent of Th0 clones were derived from GD patients and were reactive to TSH-R, whereas 50% of Th1 clones were derived from HT patients and were reactive to TPO or Tg. Most Th2 clones (82%) were reactive to TPO and were established from peripheral blood. All these clones produced IL-5, and 64% produced IL-4 and IL-10. Interestingly, IFN-gamma was highly produced by TPO- or Tg-specific clones established from HT thyroid tissue. These results confirm at the clonal level our previous studies regarding T cell epitopes on TPO and TSH-R molecules and support the concept that immunodominant T cell epitopes are located on amino acid residues 100-119 and 625-644 of TPO in HT and amino acid residues 158-176, 207-222 and 343-362/357-376 of TSH-R in GD. Our studies also demonstrate that thyroid-specific T cells can be classified into Th0, Th1, and Th2 subsets. TPO- or Tg-specific clones with Th1 phenotype appear to be involved in the pathogenesis of HT, mediating thyroid tissue destruction, whereas TSH-R clones with Th0 phenotype may induce thyroid-stimulating autoantibodies in GD.

Autoantigens↗
PubMed1994

Electronic document delivery using the Internet.

The Health Sciences Libraries Consortium (HSLC) was established in 1985 by thirteen founding member institutions in Pennsylvania and Delaware. In 1989, the Interlibrary Loan, Document Delivery, and Union List Task Force, appointed by the HSLC Board of Directors, successfully demonstrated the feasibility of supplying 94% of all interlibrary loan (ILL) photocopy requests in forty-eight hours or less by a network application of group 3-level memory telefacsimiles. However, the expenses associated with the telefacsimile operation and the limitations associated with network polling protocols challenged participants to seek new alternatives for ILL. In 1990, the HSLC introduced HSLC HealthNET, an online wide-area network linking eleven of the thirteen institutions and their resources while providing access to the Internet. The HSLC HealthNET additionally supports a centralized shared library system, several locally mounted databases, and consortiumwide electronic mail. In 1991, a project was initiated to evaluate Ariel software, pioneered by the Research Libraries Group (RLG), compared to the existing network application of group 3-level telefacsimiles. Factors identified as critical to Ariel's potential to replace the telefacsimile network were the proprietary software specifications for Internet access, the use of HSLC's existing wide-area network (WAN), and a hardware platform that was optimal for an ILL environment. This article describes the Ariel project history, the transition to Ariel from the telefacsimile network, evaluation of equipment features for processing efficiency, and operational issues affecting ILL policy.

Computer Communication Networks↗