We next analyzed if these IAVs-S possessed key molecular features associated with receptor-binding ability, increased virulence, transmission, and antiviral resistance (Table 3).Table 3Amino acid substitutions in the novel H1N1 and H3N2 reassortant isolates compared with human isolatesLineage/subtypeHostVirusNo. of glycosylation sites in HAHAaPB2M2NAc13819022522622827159059162770131274EA H1N1HumanA/Hunan/42443/20157ADEQGAGREDNYEA H1N1SwinebSw/GX/NNXD2023/20136******S*****EA H1N1SwinebSw/GX/QZ5/20146******S*****EA H1N1SwinebSw/GX/LZA3/20156******N*****EA H1N1SwinebSw/GX/NN1994/20137******S*****EA H1N1SwinebSw/GX/CZ7/20146******S*****EA H1N1SwinebSw/GX/LB9/20146******S*****EA H1N1SwinebSw/GX/BS30/20146******S*****EA H1N1SwinebSw/GX/NNLX/20146******S*****EA H1N1SwinebSw/GX/BB2/20136*****T*Q*N**EA H1N1SwinebSw/GX/GG6/20136*****T*Q*N**Early H1N1AvianA/duck/Schleswig/21/19796*EG**T*Q**S*Pandemic H1N1SwinebSw/GX/DX24/20136**D***S*****Pandemic H1N1HumanA/California/04/20096**D***S*****HL H3N2SwinebSw/GX/NNXD/20136S*DIS*S****HHL H3N2SwinebSw/GX/JGB4/20136S*DIS*S****HHL H3N2SwinebSw/GX/JG1/20146S*DIS*S****H*indicated the identical amino acids with A/Hunan/42443/2015; Sw represents swine, GX represents GuangxiaH3 numberingbisolates in this studycN2 numbering