02828     2200217   4500001002100000005001500021035002000036245027600056700002700332700001900359700002400378250002000402260000900422300004300431084001500474082001500489008003900504650002600543520202600569990001502595INLIS00000000001780420210804032621  a0010-0721002336  aCharacterization of the M2e antibody response following highly pathogenic H5N1 avian influenza virus infection and reliability of M2e ELISA for identifying infected among vaccinated chickens. /cTarigan, Simson; Indriani, Risa (IRCVS); Durr, Peter A.; Ignjatovic, Jagoada  aIndriani, Risa (IRCVS)  aDurr, Peter A.  aIgnjatovic, Jagoada  aAvian Pathology  c2015  aVol. 44 (4), 259–268.  aARTVET2077  aARTVET2077210804                |          | |   4aavian influenza virus  aA surveillance method able to differentiate between vaccinated and infected poultry is required for those countries
that practice vaccination against highly pathogenic avian influenza H5N1. The external domain of the M2 protein
(M2e) of influenza virus is a potentially useful differentiating-infected from vaccinated animals (DIVA) antigen but
little is known about the M2e antibody response and factors influencing its detection. In this study, the M2e antibody
response was characterized in layer birds vaccinated and challenged with an Indonesian H5N1 virus isolate, using a
single M2e peptide or four-branched multiple antigenic peptide form of M2e (MAP-M2e) as antigens in two
separate ELISAs. Anti-M2e antibodies were absent in chicks with high level of maternal haemagglutination
inhibition antibodies and also in all layers vaccinated once, twice or three times with an inactivated commercial
H5N1 vaccine. In contrast, anti-M2e antibodies were detected in vaccinated layers challenged with H5N1 virus and
their presence was associated with virus isolation and an increase in haemagglutination inhibition titres. The number
of birds that developed M2e antibodies, as well as the strength and duration of the M2e antibody response were
strongly influenced by the length of the interval between vaccination and challenge. Birds challenged at six weeks
after vaccination all developed M2e antibodies by 14 days that lasted until at least 56 days after infection. In birds
challenged at two weeks after vaccination, only a proportion of birds developed M2e antibodies by 14 days that
lasted only until 28 days post-infection. Both single M2e peptide and MAP-M2e ELISAs had high diagnostic
specificity but the diagnostic sensitivity of MAP-M2e ELISA was significantly higher and more effective in
detecting M2e antibody in immune and infected birds. The results show that MAP-M2e ELISA would be useful for
surveillance in countries using vaccination to control highly pathogenic avian influenza H5N1.  aARTVET2077