The disclosure includes compositions and methods for the production of an immune response against porcine reproductive and respiratory syndrome (PRRS) virus, or PRRSV. The disclosure is based in part on the use of two or more peptide domains, each with a different sequence, from the PRRSV GP5 protein ectodomain. Compositions and methods comprising polypeptides containing the two or more domains, or nucleic acids encoding them, are described.
