Polypeptide variants of the HA1 antigenic domain of the H5N1 avian influenza virus hemagglutinin (HA) molecule were produced in plants using transient and stable expression systems and fused with His/c-myc tags or with mouse or human Fc antibody fragments. The resulting peptides were purified and used for intramuscular immunization of mice. While the recombinant HA1 variants induced a significant serum humoral immune response in the mice, none of the HA1 preparations induced virus-neutralizing antibodies. Fusion with the Fc fragment improved overall yield of the constructs and allowed purification requiring only a single step, but led to no detectable fusion-related enhancement of immunogenicity or quality of immune response.
Spitsin, S; Andrianov, V; Pogrebnyak, N; Smirnov, Y; Borisjuk, N; Portocarrero, C; Veguilla, V; Koprowski, H; and Golovkin, M, "Immunological assessment of plant-derived avian flu H5/HA1 variants." (2009). Department of Cancer Biology Faculty Papers. Paper 18.