Described herein is the generation of optimized H1N1 influenza HA polypeptides for eliciting a broadly reactive immune response to H1N1 influenza virus isolates. The optimized HA polypeptides were developed through a series of HA protein alignments, and subsequent generation of consensus sequences, based on selected H1N1 viruses isolated from 1918-2011. Provided herein are optimized HlNl HA polypeptides, and compositions, fusion proteins and VLPs comprising the HA polypeptides. Further provided are codon-optimized nucleic acid sequences encoding the HA polypeptides. Methods of eliciting an immune response against influenza virus in a subject are also provided by the present disclosure.
