Effect of rFIP-nha on IL-2 release from mouse splenocytes. RFIP-nha (1, 2, 4, 8, 16, or 32 µg/mL) was used to treat mouse splenocytes for 48 h. Each bar represents mean ± SD (n = 3). ConA: positive control; PBS: negative control. **: p < 0.01, compared to negative control.