Immunogenic group A streptococcus M-related polypeptides and peptides and immunogenic compositions comprising these M-related polypeptides and peptides are provided herein that evoke cross-opsonic and cross-protective anti-GAS and anti-SDSE antibodies in animals. Also provided are preparations comprising immunogenic compositions that comprise M-related polypeptides, peptides, or fusion proteins and that further comprise at least one additional group A streptococcus immunogen, such as an M peptide or Spa peptide.
