Control of Influenza:Development of Live Vaccine / 감염과화학요법

ABSTRACT

Although trivalent subunit vaccine has been available, the influenza vaccine has been under-utilized because of cumbersome route of vaccination and low level of protection. Therefore, there has always been a great need to develop live attenuated influenza vaccine which can be administered through nasal route and elicit better immunogenicity. Through conventional repeated passage at low temperature, a live influenza vaccine carrier could be established. By reassortant formation between the 'cold- adapted' vaccine carrier and virulent strains, a prototype of trivalent live influenza vaccine is developed. Influenza A virus was adapted to replicate at low temperature. Serial passage at progressively lower temperature (30degrees C, 27degrees C and 24degrees C)resulted in the generation of cold-adapted (ca), temperature-sensitive (ts) mutant and attenuation (att) phenotype. This strain was evaluated for their ability to protect mice from challenge with same subtype and different subtype of influenza A virus. The study showed that vaccination of mice with live attenuated influenza virus provided complete protection against homologous and heterologous virus challenge. We also evaluated therapeutic potential of ca influenza virus. The mice infected with ca virus before challenge with wild type viruses or infected with simultaneously showed reduced clinical symptoms suggesting potential therapeutic effects.