Table 5.
Dynamics of HA and NA glycosylation for pH1N1 viruses isolated from MENA region during 2009–2017. In total, glycosylation patterns of 512 HA and 343 NA sequences of pH1N1 virus were analyzed. Numbers between brackets represent the percentage of sequences expressing glycosylation sequon in corresponding year while conserved glycosylation sites are indicated in bold
| Localization of potential glycosylation sequons in HA and NA of pH1N1 viruses | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| HA | ||||||||||||
| Amino acid position | ||||||||||||
| Year | Number of sequences analyzed | Stem | Head | Stem | ||||||||
| 2009 | 132 | 28 | 40 | 104 | 304 | 498 | 557 | |||||
| 2010 | 68 | 28 | 40 | 104 | 304 | 498 | 557 | |||||
| 2011 | 36 | 28 | 40 | 104 | 179 (2%) | 304 | 498 | 557 | ||||
| 2012 | 27 | 28 | 40 | 104 | 304 | 498 | 557 | |||||
| 2013 | 33 | 28 | 40 | 104 | 304 | 489* (18%) | 498 | 557 | ||||
| 2014 | 25 | 28 | 40 | 104 | 304 | 498 | 557 | |||||
| 2015 | 157 | 28 | 40 | 104 | 179 (85%) | 304 | 498 | 557 | ||||
| 2016 | 60 | 28 | 40 | 104 | 179 (99%) | 304 | 489* (2%) | 498 | 557 | |||
| NA | ||||||||||||
| Year | Number of sequences analyzed | Amino acid position | ||||||||||
| 2009 | 97 | 44 (11%) | 50 | 58 | 63 | 68 | 88 | 146 | 235 | 386 | ||
| 2010 | 42 | 42 (36%) | 50 | 58 | 63 | 68 | 88 | 146 | 235 | 386 | ||
| 2011 | 36 | 42 (100%) | 50 | 58 | 63 | 68 | 88 | 146 | 235 | 386* | ||
| 2012 | 29 | 28 (7%) | 42 (100%) | 50 | 58 | 63 | 68 | 88 | 146 | 235 | 386 | |
| 2013 | 32 | 42 (100%) | 50 | 58 | 63 | 68 | 88 | 146 | 235 | 386 | ||
| 2014 | 25 | 42 (100%) | 50 | 58 | 63 | 68 | 88 | 146 | 235 | 386 | ||
| 2015 | 79 | 42 (100%) | 50 | 58 | 63 | 68 | 88 | 146 | 235 | 386 | ||
| 2016 | 3 | 42 (100%) | 50 | 58 | 63 | 68 | 88 | 146 | 235 | |||
HA Glycosylation: glycosylation site, N489, was detected in sequences isolated from Iran. Glycosylation sequons at N28, N104, N498 and N557 were lost from viruses isolate from Iran at different time periods. In 2015, for example, N28 and N557 sequons were missing from 1.5 and 5% of HA sequences, respectively. NA Glycosylation: N386 glycosylation sequon was missing from one sequence in 2011, however, during following years more NA sequences were found to lack 386 glycosylation (31% of sequences in 2012; 80% in 2014; 77% in 2015) before disappearing completely from NA sequences in 2016