Identification of protective antigenic determinants of porcine reproductive and respiratory syndrome virus and uses thereof

A method of immunizing a pig against a porcine reproductive and respiratory syndrome virus (PRRSV) infection comprising:

• administering to a pig a first GP5-M heterodimer of porcine reproductive and respiratory syndrome virus (PRRSV), wherein the GP5 of the first GP5-M heterodimer has glycosylation at position 44 of the GP5 in a North American (NA) PRRSV strain, and wherein the position number 44 is determined from sequence alignment with the amino acid sequence of SEQ ID NO:1, or glycosylation at position 46 of the GP5 in a European (EU) PRRSV strain, and wherein the position number 46 is determined from sequence alignment with the amino acid sequence of SEQ ID NO:4;
• and
• administering to the pig a second GP5-M heterodimer of porcine reproductive and respiratory syndrome virus (PRRSV), wherein the GP5 of the second GP5-M heterodimer does not have glycosylation at position 44 of GP5 in a North American (NA) PRRSV strain, and wherein the position number 44 is determined from sequence alignment with the amino acid sequence of SEQ ID NO:1, or at position 46 in the GP5 of a European (EU) PRRSV strain, and wherein the position number 46 is determined from sequence alignment with the amino acid sequence of SEQ ID NO:4, thereby immunizing a pig against a porcine reproductive and respiratory syndrome virus (PRRSV) infection.