1. Amantadine Resistance A. Hay (MRC National Institute for Medical Research, London) VIRGIL Antiviral Training Course London, 3-6 October 2006

7. (9 subtypes) (16 subtypes)

12. Location of Ser31Asn mutation in the M2 proton channel which causes resistance to amantadine

13. Amantadine/Rimantadine resistant mutants Mutations in M2 Channel pore; residues 26,27,30,31,34 Emerge frequently in vitro and in vivo(30% or higher) Similar to wt in infectivity, virulence and transmissibility

16. Emergence of amantadine resistance in human and animal viruses Pre 1980’s – low incidence; approx. 1% Mid 1980’s – European swine viruses (sporadic human cases) 2000 - - avian H5N1,H9N2 (SE Asia) 2003 - - avian H5N1; (Z,clade 1); human cases H5N3(SE Asia) H7N2(N America) 2003 - - human H3N2 (China/Hong Kong; worldwide?)

17. Emergence of amantadine-resistant H3N2 viruses, 1994-2005 Bright et al 2005

21. ELISA: Effect of rimantadine on expression of HA in MDCK cells infected with rimantadine-sensitive and rimantadine- resistant influenza A H3N2 viruses S31N A30V +Rim

22. VirusInoculumVirus Growth (HA Titre at 70 hr p.i.) Rimantadine (  M) 00.050.55.050 A/HK/156/9710 -2 1282563284 (Sensitive)10 -3 128 1642 A/Vietnam/1194/0410 -2 128 (Resistant)10 -3 12864 A/Indonesia/5/0510 -2 1024256 3216 (Sensitive)10 -3 1024256128328 A/Indonesia/6/0510 -2 512256 (Resistant)10 -3 256 Ty/Turkey/1/0510 -2 64 1688 (Sensitive)10 -3 64 1644 Sensitivity of H5N1 Viruses to Rimantadine