Abstract
The expression and functional role of CD8 glycoprotein, a marker of cytotoxic/suppressor T lymphocytes and NK cells, were not studied on freshly isolated connective tissue type rat peritoneal mast cells, a rat mucosal type mast cell line (RBL 2H3), or human mast cell line (HMC-1). We used the reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analysis, immunohistochemistry and enzyme-linked immunosorbent assay. Results: RT-PCR and Western blot analysis identified the presence of CD8 α/β chains on the mast cells, and immunohistochemistry confirmed CD8α expression on rat or human mast cells. Functional studies demonstrated that stimulation of CD8 α/β chains on rat mast cells induced the secretion of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), which are regarded as important mediators during infection. However, co-stimulation with stem cell factor had no effect on CD8-induced mediator secretion. Our findings demonstrate novel biological roles of CD8 molecules in mast cells.
