Generation and evaluation of a high-growth reassortant H9N2 influenza A virus as a pandemic vaccine candidate.
H9N2 subtype avian influenza viruses (AIVs) are widely distributed in avian species and were isolated from humans in Hong Kong and Guangdong province, China in 1999 raising concern of their potential for pandemic spread. We generated a high-growth reassortant virus (G9/PR8) that contains the hemagglutinin (HA) and neuraminidase (NA) genes from the H9N2 avian influenza virus A/chicken/Hong Kong/G9/97 (G9) and six internal genes from A/Puerto Rico/8/34 (PR8) by genetic reassortment, for evaluation as a potential vaccine candidate in humans. Pathogenicity studies showed that the G9/PR8 reassortant was not highly pathogenic for mice or chickens. Two doses of a formalin-inactivated G9/PR8 virus vaccine induced hemagglutination inhibiting antibodies and conferred complete protection against challenge with G9 and the antigenically distinct H9N2 A/Hong Kong/1073/99 (G1-like) virus in a mouse model. These results indicate that the high growth G9/PR8 reassortant has properties that are desirable in a vaccine seed virus and is suitable for evaluation in humans for use in the event of an H9 pandemic.
Chen
Hualan
H
Influenza Branch, Mailstop G-16, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA 30333, USA.
Subbarao
Kanta
K
Swayne
David
D
Chen
Qi
Q
Lu
Xiuhua
X
Katz
Jacqueline
J
Cox
Nancy
N
Matsuoka
Yumiko
Y
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D002645:Chickens; D002681:China; D006801:Humans; D053127:Influenza A Virus, H9N2 Subtype; D009980:Influenza A virus / Q000145:classification / Q000276:immunology* / Q000302:isolation & purification / Q000472:pathogenicity / Q000502:physiology; D007252:Influenza Vaccines / Q000627:therapeutic use*; D005585:Influenza in Birds / Q000276:immunology / Q000517:prevention & control; D051379:Mice; D008807:Mice, Inbred BALB C; D014779:Virus Replication
D000914:Antibodies, Viral; D007252:Influenza Vaccines