BID and infection: In addition to cytotoxins released from CTLs, the transcript abundance of other pro-apoptotic members (Figure 6I), such as NFKBIA, growth arrest and DNA-damage-inducible protein alpha (GADD45A), BH3 interacting domain death agonist (BID), XIAP-associated factor 1 (XAF1), cytochrome c (CYCS), CASP10, was also significantly increased after infection with N-PRRSV, which can induce apoptosis of virus-infected cells.