Therefore, towards this end, we investigated the expression of host HDAC1 and its role in chromatin modulation of host defense genes and parasite survival post-infection of macrophages with L. donovani. We report that the down-regulation of key host defense genes is critical for the intracellular survival of L. donovani. Our data confirm the role of HDAC1 in the silencing of the host defense genes and enabling the intracellular survival of the parasite. This evidence concerns the gene HDAC1 and infection.