 Although animals generally express fewer variants of the dicer enzyme than plants , RNAi in some animals produces an antiviral response . In both juvenile and adult Drosophila , RNA interference is important in antiviral innate immunity and is active against pathogens such as Drosophila X virus . A similar role in immunity may operate in C. elegans , as argonaute proteins are upregulated in response to viruses and worms that overexpress components of the RNAi pathway are resistant to viral infection . 
