The invention provides a deglycosylated hemagglutinin, wherein the glycosylation site(s) on the stem region is removed. The deglycosylated hemagglutinin may induce neutralizing antibody against influenza virus, and cross-reactive protection against different virus. The invention also provides a method for manufacturing deglycosylated hemagglutinin, comprising aligning two or more hemagglutinin stem sequences of influenza virus, identifying the high conserved N-glycosylation site, and removing the high conserved N-glycosylation site. Thus, the N-glycosylation site cannot be glycosylated.
