The present invention relates to immortalized porcine alveolar macrophages (PAMs), to cell cultures comprising such PAMs, to methods for the immortalization of PAMs, to methods of replicating PRRS virus on immortalised PAMs and to methods for the preparation of vaccines comprising PRRSV.

The present invention provides exosomes isolated from an animal, wherein the animal (a) has overcome a disease caused by a pathogen, and (b) it is free from the pathogen that causes the diseases. The invention also provides process for obtaining these exosomes and the use thereof in therapy.

The present invention encompasses recombinant porcine reproductive and respiratory syndrome virus (PRRSV) vaccines or compositions. In particular, the invention encompasses recombinant adenovirus vectors encoding and expressing PRRSV gp2, gp3, gp4, gp5a, gp5 and/or E antigens, proteins, epitopes or immunogens. Such vaccines or compositions can be used to protect animals from PRRSV.

The present invention describes an efficient commercial scale production method for the preparation of PRRS virus.

The present invention relates to immortalized porcine alveolar macrophages (PAMs), to cell cultures comprising such PAMs, to methods for the immortalization of PAMs, to methods of replicating PRRS virus on immortalized PAMs and to methods for the preparation of vaccines comprising PRRSV.

The invention provides isolated polynucleotide molecules that comprise a DNA sequence encoding an infectious RNA sequence encoding a genetically-modified North American PRRS virus, methods to make it and related polypeptides, polynucleotides, and various components. Vaccines comprising the genetically modified virus and polynucleotides and a diagnostic kit to distinguish between naturally infected and vaccinated animals are also provided.

The invention provides isolated polynucleotide molecules that comprise a DNA sequence encoding an infectious RNA sequence encoding a genetically-modified North American PRRS virus, methods to make it and related polypeptides, polynucleotides, and various components. Vaccines comprising the genetically modified virus and polynucleotides and a diagnostic kit to distinguish between naturally infected and vaccinated animals are also provided.

Disclosed are an rBJ-VVL plasmid, a mutant strain of NADC34-like PRRSV-2 and a preparation method therefor and application thereof. Further disclosed is an NADC34-like PRRSV-2-specific vaccine. In the present disclosure, a modified strain rBJ-VVL with tropism for Marc-145 cells is obtained by precisely mutating an amino acid at positions 91/97/98 of GP2a; the modified virus constructed in the present disclosure can be propagated in Marc-145 cells, cause cytopathic effects and form plaques when inoculated into Marc-145 cells for serial passage; the resulting Marc-145 cell-passaged viruses have an extremely viral load, and a large number of new progeny viruses can be obtained in a short time; and the Marc-145-adapative modified strain cultured in the present disclosure is used to create a first NADC34-like PRRSV-2-specific vaccine.