Considering that both P35 and P49 are able to block apoptosis but fail to rescue viral replication in these cases, our results suggested that that either 1) apoptosis is the only block to AcMNPV infection in S. litura cells which is not consistent with our earlier results27, or 2) Se-IAP3 has another function that promotes viral replication other than inhibition of apoptosis. Here, XIAP is linked to infection.