These persistent viruses evade immune control by sequestration ( hiding away ) ; blocking antigen presentation ; cytokine resistance ; evading natural killer cell activity ; escape from apoptosis ( cell death ) , and antigenic shift ( changing surface proteins ) . These persistent viruses evade immune control by sequestration , blockade of antigen presentation , cytokine resistance , evasion of natural killer cell activities , escape from apoptosis , and antigenic shift .