Production of Influenza A/Korea/01-2-9/2009 (H1N1) Virus-like Particles from Stably Transfected Trichoplusia ni BT1 Tn 5B1-4 Cells

Virus-like particles (VLPs) are multiprotein structures that resemble the organization and conformation of native viruses. Because VLPs lack the viral genetic materials, they potentially provide safer and cheaper vaccine candidates. Influenza is a serious human respiratory disease affecting human health and the global economy. Recently, influenza VLP vaccines have been suggested to provide stronger and longer lasting protection against influenza viruses than conventional vaccines. Four major envelop proteins, matrix protein 1 (M1), matrix protein 2 (M2), hemagglutinin (HA) and neuraminidase (NA), can be used as useful materials for developing VLP vaccines. Here, stably transfected lepidopteran insect Trichoplusia ni BT1 Tn 5B1-4 (Tn5) cells expressing M1, M2, HA and NA of influenza A/Korea/01-2-9/2009 (H1N1) virus were generated to develop influenza VLP vaccine candidates. Full length M1, M2, HA and NA cDNA were generated by RT-PCR and cloned into pIZTx2 to generate pIZTx2/M1-M2 and pIZTx2/HA-NA. Stably transfected polyclonal Tn5 cell populations were isolated after 5 weeks of transfection and selection with zeocin. The expression of M1, M2 HA, and NA from stably transfected Tn5 cells were confirmed by Western blot analysis. VLPs composed of M1, M2, HA and NA were centrifuged from culture medium through a 30% sucrose cushion. Furthermore, VLPs were purified by sucrose gradient ultracentrifugation. The morphology of influenza VLPs will be examined by electron microscopy. This work was supported by a grant from the Next-Generation BioGreen 21 Program (PJ009526), Rural Development Administration, Republic of Korea.