The respiration and mitogenesis of murine splenocytes, which were measured by means of measuring the mitochondrial-dependent reduction of XTT to formazan and the uptake of BrdU, respectively, were taken as indices of the proliferation and viability of APP-treated cells. APP (2.5–40 μg/ml) alone promotes the release of XTT formazan and the uptake of BrdU in murine splenocytes (Fig. 4) (p