Staphylococcus aureus Hla polypeptides having various deletions, insertions, and/or mutations which are useful for immunization are provided herein. Also provided herein are Hla heptamers which are non-haemolytic. Additionally, an effective Staphylococcus aureus vaccine may require several antigenic components, and so various combinations of S. aureus antigens, including Hla polypeptides having deletions, insertions, and/or mutations, are identified for use in immunization. These polypeptides may optionally be used in combination with S. aureus saccharides.