The present invention relates to a recombinant DNA molecule encoding a mutated hemagglutinin protein, wherein the mutated hemagglutinin protein consists of the amino acid sequence of SEQ ID NO: 2 with one or more mutations at amino acid residue selecting from the group consisting of residue 83, 127, 138 and the combination thereof. The present invention also relates to a composition comprising the recombinant DNA molecule as described above and a pharmaceutically or veterinarily acceptable carrier, excipient, adjuvant, or vehicle. The present invention further relates to a kit for prime-boost vaccination, comprising at least a composition comprising a recombinant DNA molecule as described above and at least a composition for the boost-vaccination comprising a recombinant hemagglutiinin protein or a virus-like particle, wherein the recombinant hemagglutiinin protein is the corresponding hemagglutiinin protein encoded by the recombinant DNA molecule. The present invention still further relates to a method of vaccinating a subject susceptible to avian influenza comprising administrating to the subject an effective amount of the composition as described above. The present invention still further relates to a recombinant hemagglutinin protein consisting of the amino acid sequence of SEQ ID NO: 2 with one or more mutations at amino acid residue selecting from the group consisting of residue 83, 127, 138, and the combination thereof.
