Exosomes and their use as vaccine

A Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) free immunogenic pharmaceutical or veterinary composition comprising:

• an enriched fraction of immunogenic exosomes having immunogenic pathogenic peptides on its surface, wherein:
• the exosomes are isolated from a biological fluid sample of a non-viremic swine which (a) has overcome a respiratory disease caused by a PRRSV, and (b) it is free from the PRRSV that causes the disease, wherein the features (a) and (b) are determined in the body fluid sample of the swine by performing RT-PCR and detecting PRRSV antibodies, wherein the swine has overcome the disease and it is free from the pathogen when it is RT-PCR negative and antibodies for PRRSV are detected;
• wherein the exosome comprises a peptide comprising a sequence selected from the group consisting of SEQ ID NO:
• 1 to SEQ ID NO:
• 5, and a peptide with an identity sequence of at least 85% with any of the sequences SEQ ID NO:
• 1 to 5;
• and wherein the pathogen-free immunogenic pharmaceutical or veterinary composition comprises one or more pharmaceutically or veterinary acceptable adjuvants and one or more pharmaceutically or veterinary acceptable excipients or carriers.