Patent ID: 7390619

Claim:
A method for obtaining an optimized immunomodulatory polynucleotide, comprising: (a) creating a library of mutant polynucleotides from at least two nucleic acids, wherein each nucleic acid encodes a B7-1 (CD80) protein and the nucleic acids differ from each other in at least two nucleotides; (b) introducing the library of mutant polynucleotides into a genetic vaccine vector that encodes an antigen to form a library of vectors; (c) introducing the library of vectors into cells; (d) expressing the library of vectors in the cells; (e) screening the library to identify at least one optimized mutant polynucleotide encoding a mutant B7-1 protein that is a costimulator having an improved ability to activate a T cell response induced by the genetic vaccine vector and exhibiting an increased activity through CD28 and a decreased activity through CTLA-4 compared to a B7-1 protein encoded by a nucleic acid from which the library was created; (f) recombining at least one optimized mutant polynucleotide from (e) with at least one further mutant polynucleotide from (a) to produce a further library of mutant polynucleotides; (g) screening the further library of mutant polynucleotides of (f) to identify at least one further optimized mutant polynucleotide encoding a mutant B7-1 protein that is a costimulator having an improved ability to activate a T cell response induced by the genetic vaccine vector and exhibiting an increased activity through CD28 and a decreased activity through CTLA-4 compared to a B7-1 protein encoded by a nucleic acid from which the further library was created; and (h) repeating (f) and (g), if necessary, to identify at least one further optimized mutant polynucleotide encoding a mutant B7-1 protein that is a costimulator having an improved ability to activate a T cell response induced by the genetic vaccine vector and exhibiting an increased activity through CD28 and a decreased activity through CTLA-4 compared to a B7-1 protein encoded by a nucleic acid from which the further library was created.