Stabilized soluble pre-fusion rsv f proteins

A recombinant polypeptide comprising F1 and F2 domains of a variant pre-fusion respiratory syncytial virus (RSV) Fusion (F) protein and a fibritin trimerization domain, wherein the variant RSV F protein contains mutations consisting of a mutation of the amino acid residue at position 67 to Ile, a mutation of the amino acid residue at position 215 to Pro, a mutation of the amino acid residue at position 66 to Glu, a mutation of the amino acid residue at position 76 to Val, and a mutation of the amino acid residue at position 486 to Asn, wherein the amino acid residue position is numbered as in the full length wild type RSV A2 F protein including a signal peptide.

A recombinant polypeptide comprising F1 and F2 domains of a variant pre-fusion respiratory syncytial virus (RSV) Fusion (F) protein and a fibritin trimerization domain linked to the amino acid residue 495 of the F1 domain, wherein the variant RSV F protein contains mutations consisting of mutations of N67I, S215P, K66E, I76V and D486N, and the fibritin trimerization domain comprises the amino acid sequence of SEQ ID NO:

• 23, wherein the amino acid residue position is numbered as in the full length wild type RSV A2 F protein including a signal peptide.

A recombinant polypeptide comprising F1 and F2 domains of a variant pre-fusion respiratory syncytial virus (RSV) Fusion (F) protein and a fibritin trimerization domain, wherein the recombinant polypeptide comprises the amino acid sequence of SEQ ID NO:

• 1.