rhCTLA4Ig induces immune tolerance in mixed murine splenocyte coculture
Background It was necessary for T lymphocyte complete activation of both MHC-Ag stimulation and costimulatory pathways, in which B7-CD28 was the most important one. Blockade or deficiency of this pathway, T cell would not be activated. Competing with CD28, CTLA4Ig could bind with B7 expressed on APC to block the B7-CD28 costimulation pathway and inhibit T cell activation completely, moreover, it could induce T cell anergy, apoptosis or clone deletion, and in some models, it was said that this could induce immune tolerance and prolong grafts survival permanently.
Object To survey the role of rhCTLA4Ig in T lymphocyte activation and immune tolerance induction in mixed murine splenocyte coculture.
Materials and methods rhCTLA4Ig prepared by genetic engineering was added to the mixed spenocyte coculture from Balb/c and C57BL6 mice, respectively, the spenocyte proliferation was determined by MTT method, IL-2 production by ELISA, apoptosis was observed by dye stain. Then restimulating with different radiated spenocytes repsectively from Balb/c, C57BL6, C3H mice and Wistar rat, the proliferation and IL-2 production was checked again.
Result 1. CTLA4Ig could inhibit T lymphocyte proliferation and IL-2 production in mixed splenocyte coculture. 2. CTLA4Ig could induce T lymphocyte apoptosis in MLR. 3. After CTLA4Ig pretreated in the MLR, the radiated splenocytes from the same strain mice could not restimulate splenocyte proliferation and IL-2 production, but these from any other strain mice or rat could.
Conclusion rhCTLA4Ig could inhibit T lymphocyte activation and could induce tolerance successfully in vitro.