Glycoprotein of Rhus verniciflua Stokes (RVS glycoprotein) was isolated and identified using SDS-PAGE. To study the anti-apoptotic effects of RVS glycoprotein on mouse splenocytes, splenocytes were exposed to 100 nM TPA (61.68 ng/ml) for 3 h with or without RVS glycoprotein (100 microg/ml). Results from our experiment showed that RVS glycoprotein protects from splenocyte apoptosis induced by 12-O-tetradecanoylphorbol 13-acetate (TPA). We also studied the effects of RVS glycoprotein on the proliferation of T/B cells and the production of cytokines. Our results showed that Concanavalin A (Con A)-induced T cell proliferation and the production of interleukin-2 (IL-2)/interleukin-4 (IL-4) were reduced, and that Lipopolysaccharide (LPS)-induced B cell proliferation and the Tumor necrosis factor alpha (TNF-alpha) were reduced significantly by the addition of 50 microg/ml RVS glycoprotein (P<0.01), compared to the control. These results indicate that RVS glycoprotein has the capacity to modulate apoptosis, cytokine production and T/B cell proliferation in splenocytes.