[1] Macfarlane Burnet Inst Med Res & Publ Hlth, Virol Program, Melbourne, Vic 3004, Australia
[2] Monash Univ, Dept Biochem & Mol Biol, Clayton, Vic, Australia
[3] Monash Univ, Dept Microbiol, Clayton, Vic 3168, Australia
[4] Monash Univ, Dept Med, Prahran, Vic, Australia