Molecular vaccine linking intercellular spreading protein to an antigen
Superior molecular vaccines comprise nucleic acids, including naked DNA and replicon RNA, that encode a fusion polypeptide that includes an antigenic peptide or polypeptide against which an immune response is desired. Fused to the antigenic peptide is an intercellular spreading protein, in particular a herpes virus protein VP22 or a homologue or functional derivative thereof. Preferred spreading proteins are VP22 from HSV-1 and Marek's disease virus. The nucleic acid can encode any antigenic epitope of interest, preferably an epitope that is processed and presented by MHC class I proteins. Antigens of pathogenic organisms and cells such as tumor cells are preferred. Vaccines comprising HPV-16 E7 oncoprotein are exemplified. Also disclosed are methods of using the vaccines to induce heightened T cell mediated immunity, in particular by cytotoxic T lymphocytes, leading to protection from or treatment of a tumor.
1. A recombinant nucleic acid molecule encoding a fusion or chimeric polypeptide, which molecule comprises:
(a) a first nucleic acid sequence encoding a first polypeptide that comprises at least one Marek's Disease Virus (MDV) VP22 protein comprising SEQ ID NO: 28, or a homologue of the polypeptide comprising an amino acid sequence that is at least about 90% identical to SEQ ID NO: 28; and
(b) a second nucleic acid sequence that is linked in frame to said first nucleic acid sequence and that encodes an antigenic polypeptide or peptide from Human Papillomavirus (HPV),
wherein the first and the second nucleic acid sequences are in a self-replicating RNA replicon.
2. The nucleic acid molecule of claim 1 , wherein the antigenic polypeptide comprises an epitope that binds to, and is presented on the cell surface by, an MHC class I protein.
3. The nucleic acid molecule of claim 2 , wherein said epitope is between about 8 and about 11 amino acid residues in length.
4. The nucleic acid molecule of claim 1 , further comprising a linker fused in frame to the first and the second nucleic acid sequences.
5. The nucleic acid molecule of claim 1 , wherein the antigen is the E7 polytide of HPV-16 or an antigenic fragment therof.
6. The nucleic acid molecule of claim 1 , wherein the self-replicating replicon is a Sindbis virus RNA replicon.
7. The nucleic acid molecule of claim 4 , wherein the Sindbis virus RNA replicon is SINrep5.
8. The nucleic acid molecule of claim 5 , wherein the E7 polypeptide comprises SEQ ID NO: 27.
9. The nucleic acid of claim 1 , which is DNA coated on a gold particle.