Abstract: Disclosed is a method for improving folding efficiency and solubility of a target protein linked to a RNA-binding protein by using RNA molecule as a molecular chaperone, wherein the RNA molecule interacts with the RNA-binding protein. More particularly, the present invention discloses method for improving folding efficiency and solubility of a target protein by transformation of a host cell with a expression vector comprising a polynucleotide encoding the target protein linked to an RNA-binding protein; culturing the transformed host cell in an appropriate culture medium under the condition that an RNA molecule either resident inside the host cell or provided by cotransformation of the host cell with polynucleotide encoding the RNA molecule interacts with the RNA-binding protein; and purifying the soluble protein from host cell lysate. The method of the present invention is very useful for production of soluble proteins for therapeutic, prophylactic and diagnostic applications.

Abstract: The present invention relates to an isolated attenuated influenza virus strain and a live vaccine comprising the same. The isolated attenuated influenza virus strain is prepared by cold-adaptation of a mother strain which carries 6 internal genomes of A/PR/8/34(H1N1) and two surface antigens HA and NA of A/Aichi/2/68(H3N2). The attenuated influenza virus strain and the live vaccine of the present invention are useful for prevention of seasonal influenza episodes and sudden outbreak of influenza pandemics of predicted or unknown identity, since they have safety, efficacy, high production yield, immediate protection against variety of influenza subtypes and prolonged protection against specific influenza subtype.