CD28 and systemic lupus erythematosus: Freshly isolated CD4+ T lymphocytes from pristane-induced lupus mice were activated with anti-CD3/CD28 antibodies (3 μg/ml) and interleukin-2 (IL-2) (200 U/ml) with or without resveratrol (0, 10, 20, 40, or 80 μM).