Nucleic acid molecules comprising a nucleotide sequence encoding RANTES and fragments and variants thereof are disclosed. Additionally, nucleic acid molecules and compositions comprising the nucleotide sequence encoding RANTES and fragments and variants thereof in combination with nucleic acid sequences encoding immunogens are provided. Recombinant viral vectors comprising the nucleotide sequence encoding RANTES and fragments and variants thereof with or without a nucleic acid sequence encoding immunogens are also provided as are live attenuated pathogens comprising a nucleotide sequence encoding RANTES and fragments and variants thereof. Methods of modulating immune responses and of inducing an immune response against an immunogen are also disclosed.