The present disclosure generally relates to viral-based expression systems suitable for the production of molecule of interests in recombinant host cells. The disclosure particularly relates to nucleic acid constructs, such as expression vectors, containing a modified arterivirus genome or replicon RNA in which at least some of its original viral sequence has been deleted. Also included in the disclosure are viral-based expression vectors including one or more expression cassettes encoding heterologous polypeptides. In some embodiments, the expression cassettes are configured and positioned at defined locations on the viral genome so as to enable expression of the heterologous polypeptides in a tunable manner.

The present disclosure generally relates to viral-based expression systems suitable for the production of molecule of interests in recombinant host cells. The disclosure particularly relates to nucleic acid constructs, such as expression vectors, containing a modified arterivirus genome or replicon RNA in which at least some of its original viral sequence has been deleted. Also included in the disclosure are viral-based expression vectors including one or more expression cassettes encoding heterologous polypeptides. In some embodiments, the expression cassettes are configured and positioned at defined locations on the viral genome so as to enable expression of the heterologous polypeptides in a tunable manner.

The present disclosure generally relates to viral-based expression systems suitable for the production of molecule of interests in recombinant host cells. The disclosure particularly relates to nucleic acid constructs, such as expression vectors, containing a modified arterivirus genome or replicon RNA in which at least some of its original viral sequence has been deleted. Also included in the disclosure are viral-based expression vectors including one or more expression cassettes encoding heterologous polypeptides. In some embodiments, the expression cassettes are configured and positioned at defined locations on the viral genome so as to enable expression of the heterologous polypeptides in a tunable manner.

The present invention relates to modified, live Porcine Reproductive and Respiratory Syndrome viruses. Viruses were genetically analyzed and selected based on phylogenetic grouping for modification by repeated passage in tissue culture. The modified, live viruses were assessed for the ability to provide protective immunity to heterologous viruses. The modified, live viruses are useful in vaccines, particularly in vaccines which can treat infection of swine by multiple heterologous viruses.

The present invention relates to a method for preparing cDNA infectious clones based on the genome of an attenuated Porcine Reproductive and Respiratory Syndrome virus (PRRSV) and uses thereof for preparing efficacious and safety-enhanced vaccines against PRRSV. The invention further comprises an infectious cDNA clone obtainable by such method. The invention further provides an attenuated modified PRRSV, and immunogenic compositions and vaccines comprising that attenuated PRRSV. The present invention further provides the attenuated PRRSV for use in the prophylaxis and/or the treatment of PRRSV infections, and the attenuated PRRSV for use as vaccine or medicament in the prophylaxis and/or the treatment of PRRSV infections.

The present invention relates to modified, live Porcine Reproductive and Respiratory Syndrome viruses. Viruses were genetically analyzed and selected based on phylogenetic grouping for modification by repeated passage in tissue culture. The modified, live viruses were assessed for the ability to provide protective immunity to heterologous viruses. The modified, live viruses are useful in vaccines, particularly in vaccines which can treat infection of swine by multiple heterologous viruses.

A non-naturally occurring porcine reproductive and respiratory syndrome virus (PRRSV) is provided herein, and methods of making and using the non-naturally occurring PRRSV also are provided.

The present invention relates to porcine reproductive and respiratory syndrome virus (PRRSV) vaccines in a field of veterinary biological products, and more particularly to a PRRSV SX-105 strain having a deposit number of CGMCC No. 9906, and a use thereof in preparing PRRSV live vaccines. PRRSV SX-1 original strains are strongly pathogenic to swine. A PRRSV SX-105 attenuated strain shows safety and good immunogenicity on the swine. The PRRSV live vaccines, prepared from the PRRSV SX-105 strain, are safe and reliable, and able to generate strong immunity after immunization. The PRRSV live vaccines significantly decrease morbidity and mortality in inoculated swine groups, and have immunization effects reaching and slightly better than conventional commercial vaccines on the market, showing advantages to compete with the same kind of products around the world. The PRRSV live vaccines are capable of effectively preventing PRRS epidemic and transmission, and has broad application prospects.

A non-naturally occurring porcine reproductive and respiratory syndrome virus (PRRSV) is provided herein, and methods of making and using the non-naturally occurring PRRSV also are provided.

A non-naturally occurring porcine reproductive and respiratory syndrome virus (PRRSV) is provided herein, and methods of making and using the non-naturally occurring PRRSV also are provided.