Abstract: A fusion protein for use as a hepatitis B therapeutic vaccine is disclosed. The fusion protein comprises: (a) an antigen-presenting cell (APC)-binding domain or a CD91 receptor-binding domain; (b) a protein transduction domain; and (c) an antigen comprising a hepatitis B virus X protein deletion mutant that lacks amino acids (aa) at least from as 21 to as 50. The protein transduction domain is a fusion polypeptide comprising a T cell sensitizing signal-transducing peptide, a linker, and a translocation peptide. The APC-binding domain or the CD91 receptor-binding domain is located at the N-terminus of the fusion protein, and the antigen is located at the C-terminus of the protein transduction domain.

Abstract: Vaccine compositions for use in inducing enhanced antigen-specific T cell-mediated immune responses in a subject in need thereof are disclosed. The composition comprises (a) a therapeutically effective amount of an immunogenic protein comprising at least an antigen of a pathogen; (b) a saponin-base adjuvant selected from the group consisting of GPI-0100, Quil A, QS-21; and (c) a Toll-like receptor (TLR) agonist adjuvant selected from the group consisting of monophosphoryl lipid A (MPL), and CpG1826.

Abstract: A fusion protein for use as an immunogen enhancer for enhancing antigen-specific T cell responses is disclosed. The fusion protein comprises: (a) an antigen-presenting cell (APC)-binding domain or a CD91 receptor-binding domain; (b) a protein transduction domain; and (c) an antigen of a pathogen, wherein the APC-binding domain or the CD91 receptor-binding domain is located at the N-terminus of the fusion protein, and the antigen of the pathogen is located at the C-terminus of the protein transduction domain. The protein transduction domain is selected from the group consisting of: (i) a fusion polypeptide, comprising a T cell sensitizing signal-transducing peptide, a linker, and a translocation peptide; (ii) a T cell-sensitizing signal-transducing peptide; and (iii) a translocation peptide of 34-112 amino acid residues in length.

Abstract: A vaccine composition comprising a fusion protein for inducing enhanced pathogen antigen-specific T cell responses is disclosed. The fusion protein comprises: (a) an antigen-presenting cell (APC)-binding domain or a CD91 receptor-binding domain, located at the N-terminus of the fusion protein; (b) a translocation peptide of 34-112 amino acid residues in length, comprising an amino acid sequence that is at least 90% identical to SEQ ID NO: 4, 2, 3, or 6, located at the C-terminus of the APC-binding domain or the CD91 receptor-binding domain; and (c) an antigen of a pathogen, located at the C-terminus of the translocation peptide; (d) a nuclear export signal, comprising the amino acid sequence of SEQ ID NO: 13; and (e) an endoplasmic reticulum retention sequence, located at the C-terminus of the fusion protein.

Abstract: A fusion protein for use as an immunogen enhancer for enhancing antigen-specific T cell responses is disclosed. The fusion protein comprises: (a) an antigen-presenting cell (APC)-binding domain or a CD91 receptor-binding domain; (b) a protein transduction domain; and (c) an antigen of a pathogen, wherein the APC-binding domain or the CD91 receptor-binding domain is located at the N-terminus of the fusion protein, and the antigen of the pathogen is located at the C-terminus of the protein transduction domain. The protein transduction domain is selected from the group consisting of: (i) a fusion polypeptide, comprising a T cell sensitizing signal-transducing peptide, a linker, and a translocation peptide; (ii) a T cell-sensitizing signal-transducing peptide; and (iii) a translocation peptide of 34-112 amino acid residues in length.

Abstract: A vaccine composition comprising a fusion protein for inducing enhanced pathogen antigen-specific T cell responses is disclosed. The fusion protein comprises: (a) an antigen-presenting cell (APC)-binding domain or a CD91 receptor-binding domain, located at the N-terminus of the fusion protein; (b) a translocation peptide of 34-112 amino acid residues in length, comprising an amino acid sequence that is at least 90% identical to SEQ ID NO: 4, 2, 3, or 6, located at the C-terminus of the APC-binding domain or the CD91 receptor-binding domain; and (c) an antigen of a pathogen, located at the C-terminus of the translocation peptide; (d) a nuclear export signal, comprising the amino acid sequence of SEQ ID NO: 13; and (e) an endoplasmic reticulum retention sequence, located at the C-terminus of the fusion protein.

Abstract: A vaccine composition comprising a fusion protein for inducing enhanced pathogen antigen-specific T cell responses is disclosed. The fusion protein comprises: (a) an antigen-presenting cell (APC)-binding domain or a CD91 receptor-binding domain, located at the N-terminus of the fusion protein; (b) a translocation peptide of 34-112 amino acid residues in length, comprising an amino acid sequence that is at least 90% identical to SEQ ID NO: 4, 2, 3, or 6, located at the C-terminus of the APC-binding domain or the CD91 receptor-binding domain; and (c) an antigen of a pathogen, located at the C-terminus of the translocation peptide; (d) a nuclear export signal, comprising the amino acid sequence of SEQ ID NO: 13; and (e) an endoplasmic reticulum retention sequence, located at the C-terminus of the fusion protein.

Abstract: A fusion protein for use as an immunogen enhancer for enhancing antigen-specific T cell responses is disclosed. The fusion protein comprises: (a) an antigen-presenting cell (APC)-binding domain or a CD91 receptor-binding domain; (b) a protein transduction domain; and (c) an antigen of a pathogen, wherein the APC-binding domain or the CD91 receptor-binding domain is located at the N-terminus of the fusion protein, and the antigen of the pathogen is located at the C-terminus of the protein transduction domain. The protein transduction domain is selected from the group consisting of: (i) a fusion polypeptide, comprising a T cell sensitizing signal-transducing peptide, a linker, and a translocation peptide; (ii) a T cell-sensitizing signal-transducing peptide; and (iii) a translocation peptide of 34-112 amino acid residues in length.

Abstract: A method for inducing HIV antigen-specific immune responses is disclosed. The method comprises administering to a subject in need thereof a therapeutically effective amount of a chimeric fusion protein comprising: (a) a first polypeptidyl region comprising a Pseudomonas Exotoxin A (PE) binding domain and a PE translocation domain, located at the N-terminus of the fusion protein; and (b) a second polypeptidyl region with a fusion peptide of HIV gp120-C1-C5-gp41 with the amino acid sequence of SEQ ID NO: 7. A method for inducing neutralizing antibodies against HIV-1 is also disclosed.