Biomedical subjects

C S Hsieh

Publications and source records attributed to C S Hsieh.

22 records · Page 2Linked to original sources

PubMed1993

Dendritic cells and macrophages are required for Th1 development of CD4+ T cells from alpha beta TCR transgenic mice: IL-12 substitution for macrophages to stimulate IFN-gamma production is IFN-gamma-dependent.

We have examined the antigen presenting cell (APC) requirements for primary T cell activation and T helper (Th) cell phenotype differentiation using naive CD4+ T cells from alpha beta TCR transgenic mice. Purified dendritic cells were the principal cell required for induction of primary ovalbumin peptide specific T cell activation and clonal expansion. However, dendritic cells did not induce differentiation of T cells toward Th1 or Th2 phenotype. Addition of IL-4 during primary dendritic cell stimulations of T cells resulted in the development of a Th2 phenotype which produced high levels of IL-4 during secondary and tertiary stimulation. In contrast, development of Th1 cells producing high levels of IFN-gamma could not be induced with dendritic cells alone but required the addition of appropriately activated macrophages. Addition of splenic or peritoneal B cells did not induce Th1 development. Activated splenic macrophages induced Th1 development via a non-MHC restricted mechanism. Thus, requirements for induction of proliferation of naive CD4+ T cells are distinct from those directing Th1 phenotype development. IL-12 could replace the requirement for macrophages to induce Th1 development when T cells were activated with dendritic cells. Furthermore, this IL-12 mediated development of Th1 cells producing high levels of IFN-gamma was dependent on IFN-gamma.

Animals↗

PubMed1992

Differential regulation of T helper phenotype development by interleukins 4 and 10 in an alpha beta T-cell-receptor transgenic system.

To address the mechanisms controlling T helper (Th) phenotype development, we used DO10, a transgenic mouse line that expresses the alpha beta T-cell receptor from an ovalbumin-reactive T hybridoma, as a source of naive T cells that can be stimulated in vitro with ovalbumin peptide presented by defined antigen-presenting cells (APCs). We have examined the role of cytokines and APCs in the regulation of Th phenotype development. Interleukin 4 (IL-4) directs development toward the Th2 phenotype, stimulating IL-4 and silencing IL-2 and interferon gamma production in developing T cells. Splenic APCs direct development toward the Th1 phenotype when endogenous IL-10 is neutralized with anti-IL-10 antibody. The splenic APCs mediating these effects are probably macrophages or dendritic cells and not B cells, since IL-10 is incapable of affecting Th phenotype development when the B-cell hybridoma TA3 is used as the APC. These results suggest that early regulation of IL-4 and IL-10 in a developing immune response and the identity of the initiating APCs are critical in determining the Th phenotype of the developing T cells.

Animals↗

PubMed1991

Mechanisms of lysis by cytotoxic T lymphocyte clones. Lytic activity and gene expression in cloned antigen-specific CD4+ and CD8+ T lymphocytes.

Cloned murine Th having properties of either Th1 or Th2 cells as well as CD8+ CTL were tested for the capacity to lyse: 1) nucleated target cells bearing Ag or coated with anti-CD3 mAb, or 2) SRBC target cells coated with anti-CD3 mAb in a short term 51Cr-release assay. The lysis of SRBC occurs by a mechanism that does not involve nuclear degradation but presumably does involve membrane damage. Three patterns were observed: CTL and some Th2 cells lysed efficiently nucleated target cells and SRBC coated with anti-CD3 mAb. Th1 and some Th2 T cells lysed nucleated target cells but did not lyse efficiently the SRBC coated with anti-CD3 mAb. Finally, some Th2 cells failed to lyse efficiently either nucleated or SRBC targets. We also examined these clones for their expression of N-alpha-benzyloxycarbonyl-L-lysin thiobenzyl esterase activity, and for the expression of perforin or CTLA-1 (granzyme B) mRNA. Total N-alpha-benzyloxycarbonyl-L-lysin thiobenzyl esterase activity expressed by CTL and Th2 clones tended to be higher than that of Th1 cells. Perforin mRNA and CTLA-1 mRNA were readily detectable in CTL and some Th2 clones. Expression of perforin and CLTA-1 mRNA correlated well with the capacity of these clones to lyse SRBC coated with anti-CD3 mAb. Our results show that some but not all Th2 clones have lytic characteristics similar to those of CD8+ CTL. Two mechanisms appear to contribute to their lytic process, one mechanism of lysis involves membrane damage that correlates with the expression of perforin mRNA; a second mechanism involves the induction of DNA degradation in the target cells. In contrast, some CD4+ effector cells appear to lack the capacity to lyse efficiently via the mechanism involving membrane damage and may only have the lytic activity associated with the capacity to induce DNA degradation.

Animals↗

PubMedDate not supplied

Infantile hypertrophic pyloric stenosis presenting as pseudo-Bartter's syndrome and seizures: report of one case.

We report a hypertrophic pyloric stenosis case with an unusual initial presentation of seizures and Bartter's syndrome like symptoms. This case suffered from vomiting, diarrhea and poor appetite for several days, and seizures developed after these symptoms. From laboratory tests, hypochloremic and hypokalemic metabolic alkalosis associated with hyperreninemia, hyperaldosteronism and normal blood pressure were noted. Pseudo-Bartter's syndrome was diagnosed through these clinical and laboratory tests. Although the first abdominal echo was negative, we still speculated about the peculiar symptoms of vomiting and it's relationship to pseudo-Bartter's syndrome. After all, we found the hypertrophic pyloric stenosis through an upper gastrointestinal series. From these experiences, we postulated that it's very important to put the hypertrophic pyloric stenosis into the differential diagnosis of pseudo-Batter's syndrome.

Bartter Syndrome↗