Effect of endocrine disrupters on thymocytes in vitro

In a previous paper we reported that endocrine disrupters (EDs) such as 4, 4'-isopropylidene diphenol (Bisphenol A: BPA), bis(2-ethylhexyl) phthalate (EHP) stimulated proliferative responses and cytokine productions of murine spleen cells in vitro. In this paper we report our studies on the effect of EDs on murine thymocytes in vitro. EDs such as BPA, EHP and diethyl stilbesterol enhanced the proliferative responses of thymocytes. The proliferative responses of in vitro precultured thymocytes with EDs were markedly enhanced by the secondary stimulation with syngeneic spleen cells as antigen-presenting cells (syngeneic mixed lymphocyte reaction; MLR), when compared with thymocytes precultured without EDs. The responder cells were T cells, and they recognized the major histocompatibility complex (MHC) class II antigens on the antigen-presenting cells. The precultured T cells with EDs were enhanced in the production of cytokines such as interleukin (IL)-3, IL-4 and interferon-gamma. These results suggest that EDs have a modulating activity on thymocyte functions.