Peptides mimicking HIV-1 viral epitopes in the V2 loop for the GP120 surface envelope glycoprotein
The present invention relates to an isolated immunogenic peptide comprising a V2 loop fragment from HIV surface envelope glycoprotein gp120. This peptide binds specifically with antibodies in blood of patients vaccinated with a vaccine that has shown protection from HIV-1 infection, does not react with blood of matched patients who did not receive the vaccine, and can, therefore, elicit anti-HIV-1 antibodies which protect against HIV-1 infection. Other aspects of the present invention relate to an isolated immunogenic polypeptide comprising the peptide inserted into an immunogenic scaffold protein, a vaccine composition comprised of the immunogenic peptide and an immunologically or pharmaceutically acceptable vehicle or excipient as well as methods of inducing an immune response against HIV-1 and methods of detecting HIV-1.
1. An isolated, cyclized immunogenic peptide consisting of the amino acid sequence of SEQ ID NO:1.
2. The isolated immunogenic peptide of claim 1 , wherein the peptide consists of the amino acid sequence of SEQ ID NO: 7.
3. The isolated immunogenic peptide of claim 1 , wherein the peptide consists of the amino acid sequence of SEQ ID NO: 11.
4. The isolated immunogenic peptide of claim 1 , wherein the peptide consists of the amino acid sequence of SEQ ID NO: 12.
5. The isolated immunogenic peptide of claim 1 , wherein the peptide consists of the amino acid sequence of SEQ ID NO: 13.
6. The isolated immunogenic peptide of claim 1 , wherein the peptide consists of the amino acid sequence of SEQ ID NO: 14.
7. The isolated immunogenic peptide of claim 1 , wherein the peptide consists of the amino acid sequence of SEQ ID NO: 16.
8. An immunogenic composition comprising:
the cyclized immunogenic peptide of claim 1 and
an immunologically and pharmaceutically acceptable vehicle or excipient.
9. The immunogenic composition of claim 8 further comprising:
an adjuvant or immunostimulatory peptide or polypeptide that is different from said immunogenic polypeptide.
10. The immunogenic composition of claim 9 , wherein said immunostimulatory polypeptide is a cytokine.
11. The immunogenic composition of claim 9 , wherein the adjuvant is selected from the group consisting of: (a) ISAF-1 (5% squalene, 2.5% pluronic L121, 0.2% Tween 80) in phosphate buffered solution with 0.4 mg of threonyl-muramyl dipeptide; (b) de-oiled lecithin dissolved in an oil; (c) aluminum hydroxide gel; (d) a mixture of (b) and (c); (e) QS-21; (f) monophosphoryl lipid A adjuvant; and (g) incomplete Freund's adjuvant.