Table 1.
Genomic characteristics of 22 human clade 2.3.4.4 A(H5N6) viruses
| Year of isolation | Virus strainsa , b | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Sichuan/26221 | Changsha/1, Gz/39715, Gd/99710 | Yunnan/0127, Yunnan/DQ001, Yunnan/DQ002, Shenzhen/1/15, Shenzhen/TH001, Yunnan/14563, Yunnan/14564, Gd/SZ872, Gd/ZQ874 | Shenzhen/TH002, Shenzhen/TH003, Shenzhen/1/16 | Anhui/33162, Anhui/33163, Hubei/29578 | Hunan/55555, Guangxi/55726 | Fujian‐Sanyuan/21099 | |||
| 2014 | 2015 | 2016 | 2017 | ||||||
| Gene | Phenotype | Amino acid position | Amino acid substitution | ||||||
| HAc | Glycosylation site at 158 | N158D | N | N | N | N | N | N | N |
| T160A | A | A | A | A | S (Anhui/33162, Anhui/33163), A (Hubei/29578) | A | A | ||
| Receptor binding specificityd | N186K | N | N | N | N | N | N | N | |
| N193K | N | N | N | N | N | D | N | ||
| Q196R | K | K | K | K | K | K | K | ||
| N224 | N | N | N | N | N | N | N | ||
| Q226L | Q | Q | Q | Q | Q | Q | Q | ||
| G228S | G | G | G | G | G | G | G | ||
| S227N | R | R | S (Shenzhen1/15, Shenzhen/TH001, Gd/SZ872), R (the others) | S | S | R | R | ||
| S227R | |||||||||
| T318I | T | T | T | T | T | T | T | ||
| Cleavage site | 335‐348 | RERRRKR | RERRRKR | RERRRKR | RERRRKR | RERRRKR | RERRRKR | REKRRKR | |
| NAe | Oseltamivir resistance | H274Y | H | H | H | H | H | H | H |
| N294S | N | N | N | N | N | N | N | ||
| Stalk deletion | No | 58–68 deletion | |||||||
| PB2 | Increased pathogenicity in mice | E627K | E | E (Changsha/1), K (Gz/39715, Gd/99710) | E (Shenzhen/1/15, Shenzhen/TH001, Gd/SZ872, Gd/ZQ874), K (the others) | K | E (Hubei/29578), K (Anhui/33162, Anhui/33163) | E | E |
| D701N | N | D | D | D | D | D | D | ||
| Q591K | Q | Q | Q | Q | Q | Q | Q | ||
| T/I271A | T | T | T | T | T | T | T | ||
| 558 V | E | E | E | E | E | E | E | ||
| PB1 | Increased replication in mammalian cells | L473V | V | V | V | V | V | V | V |
| L598P | L | L | L | L | L | L | L | ||
| PB1‐F2 | Increased pathogenicity in mice | 57 | 11 | 11 (Gd/ZQ874), 90 (the others) | 90 (Shenzhen/TH002, Shenzhen/1/16), 76 (Shenzhen/TH003) | 34 (Hubei/29578), 90 (Anhui/33162, Anhui/33163) | 90 | 90 | |
| PA | Increased replication in mice | A36T | A | A | A | A | A | A | A |
| M1 | Increased pathogenicity in mice | N30D | N | N | N | N | N | N | N |
| T215A | A | A | A | A | A | A | A | ||
| M2 | Adamantane resistance | S31N | S | S | S (Gd/ZQ874), N (the others) | N | N | S | S |
| NS | Increased pathogenicity in mice | P42S | S | S | S | S | S | S | S |
| Deletion of aa 80‐84 | Yes | Yes | Yes (Gd/ZQ874), No (the others) | No | No | Yes | Yes | ||
| Increased pathogenicity in mice | D92E | E | E | E (Gd/ZQ874), D (the others) | D | D | E | D | |
| Presence of PDZ domain | Yes | Yes | Yes (Gd/ZQ874), No (the others) | No | No | Yes | Yes | ||
Font styles represent genetic groups to which the viruses tested belong; italic underline, A/Sichuan/26221/2014 group; italic, A/Hubei/29578/2016 group; underline, A/Fujian‐Sanyuan/21099/2017 group.
Sichuan/26221, A/Sichuan/26221/2014; Gd/99710, A/Guangdong/99710/2014; Gz/39715, A/Guangzhou/39715/2014; Changsha/1, A/Changsha/1/2014; Yunnan/0127, A/Yunnan/0127/2015; Yunnan/DQ001, A/Yunnan/DQ001/2015; Yunnan/DQ002, A/Yunnan/DQ002/2015; Shenzhen/1/15, A/Shenzhen/1/2015; ShenZhen/TH001, A/ShenZhen/TH001/2015; Yunnan/14563, A/Yunnan/14563/2015; Yunnan/1456, A/Yunnan/14564/2015; Gd/SZ872, A/_Guangdong_/SZ872/2015; Gd/ZQ874, A/_Guangdong_/ZQ874/2015; Shenzhen/1/16, A/Shenzhen/1/2016; Shenzhen/TH003, A/Shenzhen/TH003/2016; Shenzhen/TH002, A/Shenzhen/TH002/2016; Hunan/55555, A/Hunan/55555/2016; Guangxi/55726, A/Guangxi/55726/2016; Hubei/29578, A/Hubei/29578/2016; Anhui/33162, A/Anhui/33162/2016; Anhui/33163, A/Anhui/33163/2016; Fujian‐Sanyuan/21099, A/Fujian‐Sanyuan/21099/2017.
Amino acid positions of HA protein are designated by H3 numbering.
Amino acid substitution Q226L/G228S and N224K/Q226L in HA are responsible to increase the ability to bind to human‐type receptors in combination.
Amino acid positions of NA protein are designated by N2 numbering.