Defense Date

2005

Document Type

Dissertation

Degree Name

Doctor of Philosophy

Department

Microbiology & Immunology

First Advisor

Dr. John Ryan

Abstract

Objective. The aim of this study was to determine the effects of interleukin-10 on mast cell development from bone marrow progenitors.Materials and Methods. Unseparated mouse bone marrow cells were cultured in IL-3+SCF, giving rise to mast cells and monocytes/macrophages. The addition of IL-10, and the use of Signal Transducer and Activator of Transcription (STAT)3-deficient bone marrow cells were employed to measure the effects of IL-10 and STAT3 expression on cell viability, proliferation, and differentiation. Bax-deficient and Bcl-2 transgenic bone marrow cells were used to determine the importance of the mitochondria in IL-10-mediated effects.Overview. Mast cells arise from hematopoietic stem cells and continue development in either connective tissue or mucosa. Th2 cytokines have been implicated in the regulation of mast cell development and subsequent function. Mast cells have also been shown to be essential players in many Th2 immune responses. In the following study we investigate the effects of the Th2 cytokine IL-10 on mast cell development from isolated bone marrow progenitors. The addition of IL-10 to whole murine bone marrow greatly reduced cell numbers and altered the phenotype of the developing progenitor cells. The reduction in cell numbers was due to apoptosis, as judged by DNA fragmentation and caspase activation. The apoptosis observed included alteration in mitochondrial membrane potential. Furthermore, apoptosis could be reduced by the overexpression of Bcl-2 or by ablating p53 expression. Utilizing a flox/cre system we found that IL-10 mediated apoptosis required expression of Stat-3, since Stat-3 deficient bone marrow cells did not undergo apoptosis in response to IL-10. In this study we also observed significant alterations in the mast cell growth factor receptors IL-3R and c-kit. The loss of these growth factor receptors may explain the apoptosis induced by IL-10. These data demonstrate the potent regulatory capabilities of Th2 cytokines on mast cells, a central effector in the Th2 response.

Rights

© The Author

Is Part Of

VCU University Archives

Is Part Of

VCU Theses and Dissertations

Date of Submission

June 2008

Share

COinS