The Virosome as a Novel Concept for High Pathogenic Porcine Reproductive and Respiratory Syndrome Virus (HP-PRRSV) Vaccines

Porcine reproductive and respiratory syndrome virus (PRRSV) is an envelope, positive, single-strand RNA virus and is a member of the Arteriviridae family, Nidovirales order. PRRSV is the viral pathogen responsible for porcine reproductive and respiratory syndrome (PRRS) and caused reproductive failure and high rate of late abortion and early farrowing in sows and respiratory disease in all age. In 2006, a large scale outbreak of atypical PRRS occurred in China is characterized by high fever (41-42 degrees C), high morbidity (50-100%) and high mortality (20-100%). The disease was caused by a highly pathogenic PRRSV with a 30 amino acid deletions in its Nsp2 coding region. Because the PRRSV strains are genetically heterogeneous, and elicit delayed and weak cell-mediated immune (CMI) and antibody responses after vaccination the current vaccines are failed to provide sustainable disease control. Virosomes are virus-like particles, consisting of reconstituted virus envelopes without genetic material of the native virus. Since the virosomes has being similar to the original virus in terms of morphology and cell entry characteristics. Virosomes provide a vaccine platform that has the capacity to combine the antigen and an adjuvant within a single particle that could activate both the humoral and the cellular arm of the immune system. Furthermore, the virosomes are also providing a novel promising approach for the development of an efficacious vaccine against HP-PRRSV.