Inhibition of caspase activation in thymocytes by in vivo C5a blockade in CLP-induced sepsis. Cell lysates were incubated with caspase substrates: Ac-YVAD-AFC (caspase-1), Ac-DEVD-AFC (caspase-3), Ac-VEID-AFC (caspase-6), Ac-IETD-AFC (caspase-8), and Ac-LEHD-AFC (caspase-9). The cleaved AFC was detected on a Cytofluor II plate reader. The results were presented by picomoles of AFC released from substrates per microgram protein over a 2-hour incubation time. ^AP < 0.05 when compared with sham or CLP + αC5a group. All values represent means ± SEM (n = 4).