tetano
Editor, Senior Moderator
J Virol. 2015 Jan 21. pii: JVI.00025-15. [Epub ahead of print]
[h=1]Antibody Titer Has Positive Predictive Value for Vaccine Protection against Challenge with Natural Antigenic Drift Variants of H5N1 High Pathogenicity Avian Influenza Viruses from Indonesia.[/h] Swayne DE[SUP]1[/SUP], Suarez DL[SUP]2[/SUP], Spackman E[SUP]2[/SUP], Jadhao S[SUP]2[/SUP], Dauphin G[SUP]3[/SUP], Kim-Torchetti M[SUP]3[/SUP], McGrane J[SUP]4[/SUP], Weaver J[SUP]4[/SUP], Daniels P[SUP]5[/SUP], Wong F[SUP]5[/SUP], Selleck P[SUP]5[/SUP], Wiyono A[SUP]6[/SUP], Indriani R[SUP]6[/SUP], Yupiana Y[SUP]7[/SUP], Siregar ES[SUP]8[/SUP], Prajitno T[SUP]9[/SUP], Smith D[SUP]10[/SUP], Fouchier R[SUP]11[/SUP].
[h=3]Author information[/h]
[h=3]Abstract[/h] Vaccines are used in integrated control strategies to protect poultry against H5N1 high pathogenicity avian influenza (HPAI). H5N1 HPAI was first reported in Indonesia in 2003 and vaccination was initiated in 2004, but reports of vaccine failures began to emerge in mid-2005. This study investigated the role of Indonesian licensed vaccines, specific vaccine seed strains and emerging variant field viruses as causes of vaccine failures. Eleven of 14 licensed vaccines contained the manufacturer's listed vaccine seed strains, but three vaccines contained a different seed strain than listed on the label. Vaccines containing A/turkey/Wisconsin/1968 (WI/68), A/chicken/Mexico/28159-232/1994 (Mex/94) and Eng/73 seed strains had high serological potency in chickens (geometric mean HI titers ≥ 1:169), but vaccines containing reverse genetic (rg) A/chicken/Guangdong/1/1996 (rgGD/96), A/chicken/Legok/2003 (Legok/03), rgA/chicken/Vietnam/C57/2004 (rgVN/04) or rgA/chicken/Legok/2003 (rgLegok/03) had lower serological potency (geometric mean HI titers ≤ 1:95). In challenge studies, chickens immunized with any of the H5 AI vaccines were protected against A/chicken/West Java/SMI-HAMD/2006 (SMI-HAMD/06), partially protected against A/chicken/Papua/TA5/2006 (Papua/06), but were not protected against A/chicken/West Java/PWT-WIJ/2006 (PWT/06). Experimental inactivated vaccines made with PWT/06 HPAI or rgPWT/06 LPAI seed strains protected chickens from lethal challenge as did a combination of a commercially available live fowl poxvirus vaccine expressing the H5 influenza gene and inactivated Legok/03 vaccine. These studies indicate that antigenic variants did emerge in Indonesia following widespread H5 avian influenza vaccine usage, and efficacious inactivated vaccines can be developed using antigenic variant wild type viruses or rgLPAI seed strains containing hemagglutinin and neuraminidase genes of wild type viruses.
[h=4]IMPORTANCE:[/h] H5N1 high pathogenicity avian influenza (HPAI) has become endemic in Indonesian poultry and such poultry are the source of virus for birds and mammals including humans. Vaccination has become a part of the poultry control strategy but vaccine failures have occurred in the field. This study identified possible causes of vaccine failure which included use of an unlicensed virus seed strain and induction of low levels of protective antibody because of insufficient quantity of vaccine antigen. However, the most important cause of vaccine failure was the appearance of drift variant field viruses that partially or completely overcome commercial vaccine induced immunity. Furthermore, experimental vaccines using inactivated wild type or reverse genetic generated vaccines containing hemagglutinin and neuraminidase genes of wild type drift variant field viruses were protective. These studies indicate the need for surveillance to identify drift variant viruses in the field and update licensed vaccines when such variants appear.
Copyright ? 2015, American Society for Microbiology. All Rights Reserved.
PMID: 25609805 [PubMed - as supplied by publisher]
[h=1]Antibody Titer Has Positive Predictive Value for Vaccine Protection against Challenge with Natural Antigenic Drift Variants of H5N1 High Pathogenicity Avian Influenza Viruses from Indonesia.[/h] Swayne DE[SUP]1[/SUP], Suarez DL[SUP]2[/SUP], Spackman E[SUP]2[/SUP], Jadhao S[SUP]2[/SUP], Dauphin G[SUP]3[/SUP], Kim-Torchetti M[SUP]3[/SUP], McGrane J[SUP]4[/SUP], Weaver J[SUP]4[/SUP], Daniels P[SUP]5[/SUP], Wong F[SUP]5[/SUP], Selleck P[SUP]5[/SUP], Wiyono A[SUP]6[/SUP], Indriani R[SUP]6[/SUP], Yupiana Y[SUP]7[/SUP], Siregar ES[SUP]8[/SUP], Prajitno T[SUP]9[/SUP], Smith D[SUP]10[/SUP], Fouchier R[SUP]11[/SUP].
[h=3]Author information[/h]
[h=3]Abstract[/h] Vaccines are used in integrated control strategies to protect poultry against H5N1 high pathogenicity avian influenza (HPAI). H5N1 HPAI was first reported in Indonesia in 2003 and vaccination was initiated in 2004, but reports of vaccine failures began to emerge in mid-2005. This study investigated the role of Indonesian licensed vaccines, specific vaccine seed strains and emerging variant field viruses as causes of vaccine failures. Eleven of 14 licensed vaccines contained the manufacturer's listed vaccine seed strains, but three vaccines contained a different seed strain than listed on the label. Vaccines containing A/turkey/Wisconsin/1968 (WI/68), A/chicken/Mexico/28159-232/1994 (Mex/94) and Eng/73 seed strains had high serological potency in chickens (geometric mean HI titers ≥ 1:169), but vaccines containing reverse genetic (rg) A/chicken/Guangdong/1/1996 (rgGD/96), A/chicken/Legok/2003 (Legok/03), rgA/chicken/Vietnam/C57/2004 (rgVN/04) or rgA/chicken/Legok/2003 (rgLegok/03) had lower serological potency (geometric mean HI titers ≤ 1:95). In challenge studies, chickens immunized with any of the H5 AI vaccines were protected against A/chicken/West Java/SMI-HAMD/2006 (SMI-HAMD/06), partially protected against A/chicken/Papua/TA5/2006 (Papua/06), but were not protected against A/chicken/West Java/PWT-WIJ/2006 (PWT/06). Experimental inactivated vaccines made with PWT/06 HPAI or rgPWT/06 LPAI seed strains protected chickens from lethal challenge as did a combination of a commercially available live fowl poxvirus vaccine expressing the H5 influenza gene and inactivated Legok/03 vaccine. These studies indicate that antigenic variants did emerge in Indonesia following widespread H5 avian influenza vaccine usage, and efficacious inactivated vaccines can be developed using antigenic variant wild type viruses or rgLPAI seed strains containing hemagglutinin and neuraminidase genes of wild type viruses.
[h=4]IMPORTANCE:[/h] H5N1 high pathogenicity avian influenza (HPAI) has become endemic in Indonesian poultry and such poultry are the source of virus for birds and mammals including humans. Vaccination has become a part of the poultry control strategy but vaccine failures have occurred in the field. This study identified possible causes of vaccine failure which included use of an unlicensed virus seed strain and induction of low levels of protective antibody because of insufficient quantity of vaccine antigen. However, the most important cause of vaccine failure was the appearance of drift variant field viruses that partially or completely overcome commercial vaccine induced immunity. Furthermore, experimental vaccines using inactivated wild type or reverse genetic generated vaccines containing hemagglutinin and neuraminidase genes of wild type drift variant field viruses were protective. These studies indicate the need for surveillance to identify drift variant viruses in the field and update licensed vaccines when such variants appear.
Copyright ? 2015, American Society for Microbiology. All Rights Reserved.
PMID: 25609805 [PubMed - as supplied by publisher]