Composite polypeptide monomer, aggregate of said composite polypeptide monomer having cell penetration function, and norovirus component vaccine for subcutaneous, intradermal, percutaneous, or intramuscular administration and having said aggregate as effective component thereof

A composite polypeptide, which comprises a polypeptide of the following formula (1):

• W-L1-Xn-Y (1)
• wherein W is an amino acid sequence comprising a part or the entirety of a virus structural protein as an immunogen of a vaccine against the virus;
• L1 is a first linker sequence having 0 to 100 amino acids;
• X is an amino acid sequence which comprises the amino acid sequence of SEQ ID NO:
• 1, or which comprises an amino acid sequence with 8 or less amino acid sequence changes as compared to SEQ ID NO:
• 1;
• Y comprises an amino acid sequence of a cell introduction domain;
• and n is an integer between 1 and 3,
• wherein the cell introduction domain of Y comprises an amino acid sequence of the following formula (2):
• Y1-L2-Y2-Y3 (2)
• wherein Y1 is an amino acid sequence which comprises the amino acid sequence of any one of SEQ ID NOs:
• 2 to 5, or which comprises an amino acid sequence with 30 or less amino acid sequence changes as compared to any one of SEO ID NOs:
• 2 to 5;
• Y2 is an amino acid sequence which comprises the amino acid sequence of any one of SEQ ID NOs:
• 6 to 9, or which comprises an amino acid sequence with 15 or less amino acid sequence changes as compared to any one of SEQ ID NOs:
• 6 to 9;
• L2 is a second linker sequence having 0 to 30 amino acids;
• Y3 is an amino acid sequence for modification;
• and either of Y2 and Y3 may be absent,
• and wherein said amino acid changes are selected from the group consisting of additions, deletions, and substitutions.