Conformation-stabilized TRAP antigens
This invention relates to compositions and methods for eliciting an immune response against a parasite of the genus Plasmodium in a mammal.
1. A Plasmodium falciparum Thrombospondin-Related Anonymous Protein (TRAP) antigen that is at least 80% identical to amino acids 25-574 of SEQ ID NO:5, wherein the antigen sequence comprises one or more of the following mutations or deletions:
(a) Mutation at Cysteine 55 to a non-cysteine amino acid;
(b) Mutation of N-linked glycosylation sites;
(c) Mutation of Ala-216/Asn-222 or Lys-224/Gln-78 to cysteine to create a TRAP that is stabilized in the open conformation;
(d) Mutation of Asn-213/Ala-233, Ala-216/Phe-230, or Met-231/Gln-78 to cysteine to create a TRAP that is stabilized in the closed conformation;
(e) Deletion of N-terminal and/or C-terminal residues to create a TRAP fragment that is stabilized in the closed conformation comprising V47-V238;
(f) Deletion of N-terminal and/or C-terminal residues to create a TRAP fragment that is stabilized in the open conformation comprising V47-M231,
and wherein the antigen can elicit an immune response in a mammalian subject.
2. The antigen of claim 1 , wherein the sequence is a mutated P. falciparum TRAP sequence that is at least 95% identical to SEQ ID NO:5.
3. The antigen of claim 1 , wherein the mutation at Cys55 is to Glycine, Serine, or Alanine.
4. The antigen of claim 1 , wherein the mutation of an N-linked glycosylation site is a mutation of N or (S/T) in the carbohydrate-encoding sequence N-X-(S/T).
5. The antigen of claim 4 , wherein the mutation is N132S, S477N, and/or N483S.
6. A fusion protein comprising the antigen of claim 1 fused to one or more of an adjuvant, carrier, or protein purification sequence.
7. The fusion protein of claim 6 , wherein the protein purification sequence comprises a FLAG sequence or a 6His sequence.
8. The fusion protein of claim 6 , wherein the carrier comprises a hepatitis B surface protein.
9. A composition comprising one or more of the antigens or fusion proteins of claim 1 .
10. A pharmaceutical composition comprising one or more of the antigens of claim 1 and a physiologically acceptable carrier.
11. The pharmaceutical composition of claim 10 , further comprising an adjuvant.
12. A method of inducing an immune response in a mammal, the method comprising administering to the subject a pharmaceutical composition comprising one or more of the antigens of claim 1 .
13. The method of claim 12 , wherein the pharmaceutical composition further comprises an adjuvant.