Synthetic alphavirus-derived replicon expression systems comprising nucleic acid sequences encoding at least one modified nonstructural protein, and synthetic nucleic acid sequences encoding at least one heterologous protein are described. Methods of producing at least one heterologous protein in a cell, or of inducing an immune response in a subject by administering and/or expressing the synthetic alphavirus-derived replicon expression systems are provided.

Synthetic alphavirus-derived replicon expression systems comprising nucleic acid sequences encoding at least one modified nonstructural protein, and synthetic nucleic acid sequences encoding at least one heterologous protein are described. Methods of producing at least one heterologous protein in a cell, or of inducing an immune response in a subject by administering and/or expressing the synthetic alphavirus-derived replicon expression systems are provided.

Synthetic alphavirus-derived replicon expression systems comprising nucleic acid sequences encoding at least one modified nonstructural protein, and synthetic nucleic acid sequences encoding at least one heterologous protein are described. Methods of producing at least one heterologous protein in a cell, or of inducing an immune response in a subject by administering and/or expressing the synthetic alphavirus-derived replicon expression systems are provided.

Provided are polynucleotides and viral vectors, e.g., alphavins or Sindbis viral vectors, encoding multiple, e.g., two or more, epitopes of at least one tumor associated antigen, in which each epitope is separated by a processing or enzyme cleavage site. The encoded epitopes may be the same or different. Also provided are polynucleotides and viral vectors, particularly, alphavirus or Sindbis viral vectors, encoding an immune checkpoint protein, or a ligand binding portion thereof. The immune checkpoint protein or ligand binding portion thereof may be fused to immunoglobulin domains, e.g., an Ig hinge domain and an Ig heavy chain constant domain. Methods of treating subjects having a cancer or tumor, e.g., a TAA-expressing tumor, with the described viral vectors are provided. Treatment of subjects with the vectors, the checkpoint inhibitor molecules and/or other immunomodulatory components, generate an anti-cancer or anti-tumor immune response resulting in increased survivability of tumored subjects and epitope spreading.

The invention provides RNA replicons useful for administering a heterologous protein or peptide into a mammal and eliciting a reduced immune response or no immune response from the mammal. The RNA replicons have RNA sequences encoding for a heterologous protein or peptide, New World alphavirus nonstructural proteins nsP1, nsP2, and nsP4; and an alphavirus nsP3 protein macro domain, central domain, and hypervariable domain. The encoded hypervariable domain can have an amino acid sequence derived from an Old World alphavirus nsP3 hypervariable domain; or can have an amino acid sequence derived from a portion of a New World alphavirus nsP3 hypervariable domain, and another portion derived from an Old World alphavirus nsP3 hypervariable domain.

Provided is a method for modulating an immune response which is not derived from alphavirus infection comprising administering to a subject in need thereof an effective amount of a composition comprising an alphavirus virus like particle.

The present invention relates to a composition including a recombinant nucleic acid sequence that encodes an antibody and a method of generating a synthetic antibody in a subject by administering the composition to the subject. The invention also provides a method of preventing and/or treating disease in a subject using the composition and method of generation.

Provided are polynucleotides and viral vectors, e.g., alphavirus or Sindbis viral vectors, encoding multiple, e.g., two or more, epitopes of at least one tumor associated antigen, in which each epitope is separated by a processing or enzyme cleavage site. The encoded epitopes may be the same or different. Also provided are polynucleotides and viral vectors, particularly, alphavirus or Sindbis viral vectors, encoding an immune checkpoint protein, or a ligand binding portion thereof. The immune checkpoint protein or ligand binding portion thereof may be fused to immunoglobulin domains, e.g., an Ig hinge domain and an Ig heavy chain constant domain. Methods of treating subjects having a cancer or tumor, e.g., a TAA-expressing tumor, with the described viral vectors are provided. Treatment of subjects with the vectors, the checkpoint inhibitor molecules and/or other immunomodulatory components, generate an anti-cancer or anti-tumor immune response resulting in increased survivability of tumored subjects and epitope spreading.

Provided is a method for modulating an immune response which is not derived from alphavirus infection comprising administering to a subject in need thereof an effective amount of a composition comprising an alphavirus virus like particle.

The invention provides RNA replicons useful for administering a heterologous protein or peptide into a mammal and eliciting a reduced immune response or no immune response from the mammal. The RNA replicons have RNA sequences encoding for a heterologous protein or peptide, New World alphavirus nonstructural proteins nsP1, nsP2, and nsP4; and an alphavirus nsP3 protein macro domain, central domain, and hypervariable domain. The encoded hypervariable domain can have an amino acid sequence derived from an Old World alphavirus nsP3 hypervariable domain; or can have an amino acid sequence derived from a portion of a New World alphavirus nsP3 hypervariable domain, and another portion derived from an Old World alphavirus nsP3 hypervariable domain.