Influenza A virus transfectants with chimeric hemagglutinins containing epitopes from different subtypes.

Influenza virus transfectants with chimeric hemagglutinins were constructed by using a ribonucleoprotein transfection method. Transfectants W(H1)-H2 and W(H1)-H3 contained A/WSN/33(H1N1) (WSN) hemagglutinins in which the six-amino-acid loop (contained in antigenic site B) was replaced by the corresponding structures of influenza viruses A/Japan/57(H2N2) and A/Hong Kong/8/68(H3N2) (HK), respectively. Serological analysis indicated that the W(H1)-H3 transfectant virus reacted with antibodies against both the WSN and HK viruses in hemagglutination inhibition and plaque neutralization assays. Furthermore, mice immunized with W(H1)-H3 transfectant virus produced antibodies to the WSN and HK viruses. The results demonstrate that influenza virus transfectants can be engineered to express epitopes of different subtypes on their hemagglutinins.