The present invention relates to a mutated virus. Said virus can be an influenza virus of human or other animal origin. The present invention also relates to a method for preparing the mutated virus, the method comprising introducing UAG codons into positions upstream of the stop codons per se of one or more genes of a viral genome by reverse genetic techniques. The present invention further relates to uses of the mutated virus, for example, as a live attenuated vaccine, or in replication of controllable and safe virus models, and the like.

Provided is a method of producing reassortant influenza virus containing an antigenic protein of the first influenza virus strain, the method including the following steps: 1) a step of irradiating the first influenza virus strain with ultraviolet light in such an irradiation dose that the first influenza virus strain has initial infection ability and loses or is reduced in virus growth potential; 2) a step of infecting a host with the first influenza virus strain and the second influenza virus strain; 3) a step of culturing the host infected with the first influenza virus strain and the second influenza virus strain, to obtain culture product; 4) a step of inactivating influenza virus strain having an antigenic protein of the second influenza virus strain in the culture product obtained in the step 3); and 5) a step of collecting reassortant influenza virus after the step 4).

The present invention is directed to a reassorted ISA virus comprising Genome segments 1-8 wherein at least one genome segment is from Genotype I and at least one genome segment is from genotype II, wherein genome segment 6 is of Genotype II. The reassorted ISA virus was found to grow well in suspension culture. The present invention is also directed to method to make the reassorted virus as well as vaccination methods using the reassorted ISA virus and to vaccine compositions comprising the reassorted ISA virus.

This disclosure provides modified cytosine deaminases (CDs). The disclosure further relates to cells and vector expressing or comprising such modified CDs and methods of using such modified CDs in the treatment of disease and disorders.

Modified influenza virus neuraminidases are described herein that improve viral replication, thus improving the yield of vaccine viruses. Expression of such modified neuraminidases by influenza virus may also stabilize co-expressed hemagglutinins so that the hemagglutinins do not undergo mutation.

Modified influenza virus neuraminidases are described herein that improve viral replication, thus improving the yield of vaccine viruses. Expression of such modified. neuraminidases by influenza virus may also stabilize co-expressed hemagglutinins so that the hemagglutinins do not undergo mutation.

Provided is a method of producing reassortant influenza virus containing an antigenic protein of the first influenza virus strain, the method including the following steps: 1) a step of irradiating the first influenza virus strain with ultraviolet light in such an irradiation dose that the first influenza virus strain has initial infection ability and loses or is reduced in virus growth potential; 2) a step of infecting a host with the first influenza virus strain and the second influenza virus strain; 3) a step of culturing the host infected with the first influenza virus strain and the second influenza virus strain, to obtain culture product; 4) a step of inactivating influenza virus strain having an antigenic protein of the second influenza virus strain in the culture product obtained in the step 3); and 5) a step of collecting reassortant influenza virus after the step 4).

The present invention relates to a nucleic acid construct, a recombinant multiply-defective influenza virus, that promotes expression of an immunomodulatory protein in a host. This is applicable to the development of vaccines against infectious diseases, particularly those caused by influenza virus and Coronavirus.

Modified influenza virus neuraminidases are described herein that improve viral replication, thus improving the yield of vaccine viruses. Expression of such modified neuraminidases by influenza virus may also stabilize co-expressed hemagglutinins so that the hemagglutinins do not undergo mutation or decrease the need for HA binding to cells.

Methods to create barcoded influenza viruses without disrupting the function of the viral proteins and the proper packaging of the viral genome segments are described. The barcoded influenza viruses can be used within deep mutational scanning libraries to map influenza resistance mutations to therapeutic treatments. The libraries can also be used to predict influenza strains that may become resistant to therapeutic treatments and/or more easily evolve to infect new species. The libraries include features that allow efficient collection and assessment of informative data, obviating bottlenecks of previous approaches.