GO:0044356:   clearance of foreign intracellular DNA by conversion of DNA cytidine to uridine
A defense process that protects an organism from invading foreign DNA. The process begins by the deamination of foreign double-stranded DNA cytidines to uridines. These atypical DNA nucleosides are then converted by a uracil DNA glycosylase to abasic lesions, and the process ends with the degradation of the foreign DNA.