Immunogenic peptide composition and method

An immunogenic peptide composition comprising a first influenza polypeptide bound to a second influenza polypeptide;

• wherein the first influenza polypeptide consists of 16 amino acid residues and has an amino acid sequence consisting of SEQ ID NO:
• 1 or a variant of SEQ ID NO:
• 1 sharing at least 50% sequence identity therewith and differing from SEQ ID NO:
• 1 by one or more amino acid substitutions selected from the group consisting of V1I, V1L, V1A, V1G, V1T, V1S, V1M, E2D, E2K, E2R, D3E, T4G, T4S, T4Q, T4A, K5F, K5M, K5I, K5V, K5L, K5A, I6L, I6V, I6A, I6T, I6S, I6Q, I6N, D7E, L8I, L8V, L8A, W9Y, S10T, S10G, S10A, S10M, and E14K;
• and the second polypeptide consists of a full-length influenza hemagglutinin protein;
• and wherein the first polypeptide is bound to the second polypeptide either directly or through a linking group comprising a spacer peptide selected from the group consisting of a single amino acid and a non-hemagglutinin FIR peptide sequence.

An immunogenic peptide composition comprising a hemagglutinin fusion initiation region (FIR) peptide or a variant thereof bound to an influenza B hemagglutinin protein;

• wherein the FIR peptide has an amino acid sequence that consists of SEQ ID NO:
• 1 or a variant of SEQ ID NO:
• 1 sharing at least 50% sequence identity therewith and differing from SEQ ID NO:
• 1 by one or more amino acid substitutions selected from the group consisting of V1I, V1L, V1A, V1G, V1T, V1S, V1M, E2D, E2K, E2R, D3E, T4G, T4S, T4Q, T4A, K5F, K5M, K5I, K5V, K5L, K5A, I6L, I6V, I6A, I6T, I6S, I6Q, I6N, D7E, L8I, L8V, L8A, W9Y, S10T, S10G, S10A, S10M, and E14K.