BACKGROUND: Hemagglutination-inhibition (HI) antibody titers correlate with protective immunity to seasonal influenza viruses. However, inactivated H5N1 influenza vaccines from Vietnam 2004 strains afford protection without producing high or even detectable HI antibodies. METHODS: BALB/c mice were immunized twice (at a 3-week interval) with inactivated whole-virus influenza vaccine produced using reverse genetics, with the internal genes of A/PR/8/34 (a high-yield strain) and the hemagglutinin (HA) and neuraminidase (NA) genes of A/Vietnam/1194/04 (H5N1) virus (NIBRG-14) adjuvanted with alum (5 microg of HA). Either HA- or NA-binding antibodies were absorbed from the immune serum. The protective efficacy of these antibodies was determined by injecting the absorbed serum into severe combined immunodeficiency mice, which were then challenged with highly pathogenic H5N1 virus (A/Vietnam/Jp1203/2004; Japanese isolate of A/Vietnam/1203/2004). RESULTS: The NIBRG-14 vaccine elicited levels of anti-HA antibodies similar to levels elicited by the H1N1 vaccines, as well as levels of anti-NA antibodies higher than those elicited by the H1N1 vaccines. The absorption of either anti-HA or anti-NA antibody from immune serum samples obtained from NIBRG-14-vaccinated mice significantly reduced the protective efficacy of the serum. CONCLUSIONS: For NIBRG-14 vaccines to confer protection to vaccinated hosts, both anti-HA and anti-NA antibodies are required. This finding implies that the measurement of both antibody levels may be required for accurate evaluation of vaccine efficacy.
BACKGROUND: Hemagglutination-inhibition (HI) antibody titers correlate with protective immunity to seasonal influenza viruses. However, inactivated H5N1 influenza vaccines from Vietnam 2004 strains afford protection without producing high or even detectable HI antibodies. METHODS: BALB/c mice were immunized twice (at a 3-week interval) with inactivated whole-virus influenza vaccine produced using reverse genetics, with the internal genes of A/PR/8/34 (a high-yield strain) and the hemagglutinin (HA) and neuraminidase (NA) genes of A/Vietnam/1194/04 (H5N1) virus (NIBRG-14) adjuvanted with alum (5 microg of HA). Either HA- or NA-binding antibodies were absorbed from the immune serum. The protective efficacy of these antibodies was determined by injecting the absorbed serum into severe combined immunodeficiencymice, which were then challenged with highly pathogenic H5N1 virus (A/Vietnam/Jp1203/2004; Japanese isolate of A/Vietnam/1203/2004). RESULTS: The NIBRG-14 vaccine elicited levels of anti-HA antibodies similar to levels elicited by the H1N1 vaccines, as well as levels of anti-NA antibodies higher than those elicited by the H1N1 vaccines. The absorption of either anti-HA or anti-NA antibody from immune serum samples obtained from NIBRG-14-vaccinated mice significantly reduced the protective efficacy of the serum. CONCLUSIONS: For NIBRG-14 vaccines to confer protection to vaccinated hosts, both anti-HA and anti-NA antibodies are required. This finding implies that the measurement of both antibody levels may be required for accurate evaluation of vaccine efficacy.
Authors: John A Rutigliano; Melissa Y Morris; Wen Yue; Rachael Keating; Richard J Webby; Paul G Thomas; Peter C Doherty Journal: J Virol Date: 2009-11-04 Impact factor: 5.103
Authors: Thomas R Cate; Yolanda Rayford; Diane Niño; Patricia Winokur; Rebecca Brady; Robert Belshe; Wilbur Chen; Robert L Atmar; Robert B Couch Journal: Vaccine Date: 2009-12-29 Impact factor: 3.641
Authors: Francisco Miguel Cardoso; Lorena Itatí Ibañez; Silvie Van den Hoecke; Sarah De Baets; Anouk Smet; Kenny Roose; Bert Schepens; Francis J Descamps; Walter Fiers; Serge Muyldermans; Ann Depicker; Xavier Saelens Journal: J Virol Date: 2014-05-14 Impact factor: 5.103