title: Cross-protective immunity to porcine reproductive and respiratory syndrome virus by intranasal delivery of a live virus vaccine with a potent adjuvant.
abstract: Porcine reproductive and respiratory syndrome (PRRS) is an immunosuppressive chronic respiratory viral disease of pigs that is responsible for major economic losses to the swine industry worldwide. The efficacy of parenteral administration of widely used modified live virus PRRS vaccine (PRRS-MLV) against genetically divergent PRRSV strains remains questionable. Therefore, we evaluated an alternate and proven mucosal immunization approach by intranasal delivery of PRRS-MLV (strain VR2332) with a potent adjuvant to elicit cross-protective immunity against a heterologous PRRSV (strain MN184). Mycobacterium tuberculosis whole cell lysate (Mtb WCL) was chosen as a potent mucosal adjuvant due to its Th1 biased immune response to PRRS-MLV. Unvaccinated pigs challenged with MN184 had clinical PRRS with severe lung pathology; however, vaccinated (PRRS-MLV+ Mtb WCL) pigs challenged with MN184 were apparently healthy. There was a significant increase in the body weight gain in vaccinated compared to unvaccinated PRRSV challenged pigs. Vaccinated compared to unvaccinated, virus-challenged pigs had reduced lung pathology associated with enhanced PRRSV neutralizing antibody titers and reduced viremia. Immunologically, an increased frequency of Th cells, Th/memory cells, γδ T cells, dendritic cells, and activated Th cells and a reduced frequency of T-regulatory cells were detected at both mucosal and systemic sites. Further, reduced secretion of immunosuppressive cytokines (IL-10 and TGF-β) and upregulation of the Th1 cytokine IFN-γ in blood and lungs were detected in mucosally vaccinated, PRRSV-challenged pigs. In conclusion, intranasal immunization of pigs with PRRS-MLV administered with Mtb WCL generated effective cross-protective immunity against PRRSV.
authors.affiliation: Food Animal Health Research Program, Ohio Agricultural Research and Development Center, and Department of Veterinary Preventive Medicine, The Ohio State University, Wooster, OH 44691, USA.
authors.forename: Varun
authors.initials: V
authors.lastname: Dwivedi
authors.forename: Cordelia
authors.initials: C
authors.lastname: Manickam
authors.forename: Ruthi
authors.initials: R
authors.lastname: Patterson
authors.forename: Katie
authors.initials: K
authors.lastname: Dodson
authors.forename: Michael
authors.initials: M
authors.lastname: Murtaugh
authors.forename: Jordi B
authors.initials: JB
authors.lastname: Torrelles
authors.forename: Larry S
authors.initials: LS
authors.lastname: Schlesinger
authors.forename: Gourapura J
authors.initials: GJ
authors.lastname: Renukaradhya
mesh_terms: D000276:Adjuvants, Immunologic; D000281:Administration, Intranasal; D000818:Animals; D057134:Antibodies, Neutralizing / Q000097:blood; D000914:Antibodies, Viral / Q000097:blood; D056738:Cross Protection; D016207:Cytokines / Q000378:metabolism; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D019318:Porcine Reproductive and Respiratory Syndrome / Q000276:immunology / Q000517:prevention & control* / Q000821:virology; D019316:Porcine respiratory and reproductive syndrome virus / Q000276:immunology*; D013552:Swine; D018417:Th1 Cells / Q000276:immunology; D014611:Vaccination / Q000662:veterinary; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000276:immunology* / Q000627:therapeutic use; D014765:Viral Vaccines / Q000008:administration & dosage / Q000276:immunology* / Q000627:therapeutic use
chemical_list: D000276:Adjuvants, Immunologic; D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D016207:Cytokines; D014613:Vaccines, Attenuated; D014765:Viral Vaccines