Cationic liposome-encapsulated antisense oligonucleotide mediates efficient killing of intracellular Leishmania

Antisense oligonucleotides have been considered as inhibitors of growth of intracellular parasites such as Leishmania, but only limited inhibition has been observed in vitro. We have encapsulated an antisense oligonucleotide, complementary to the Leishmania universal miniexon sequence, in cationic l iposomes. Low concentrations (4 mu M) of encapsulated oligonucleotides spec ifically reduced the amastigote burden within cultured macrophages by 80%. This result illustrates the importance of effective delivery for efficient antiparasitic activity of antisense oligonudeotides.