Immune response and protective efficacy of intramuscular and intradermal vaccination with porcine reproductive and respiratory syndrome virus 1 (PRRSV-1) modified live vaccine against highly pathogenic PRRSV-2 (HP-PRRSV-2) challenge, either alone or in combination with of PRRSV-1

• Published in: Veterinary microbiology Vol. 244; p. 108655
• Main Authors: Madapong, Adthakorn, Saeng-chuto, Kepalee, Chaikhumwang, Puwich, Tantituvanont, Angkana, Saardrak, Kriangsak, Pedrazuela Sanz, Rafael, Miranda Alvarez, Joel, Nilubol, Dachrit
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.05.2020; Elsevier BV
• Subjects: Animal diseases; Animals; Antibodies, Viral - blood; Antibody response; Challenge; Hogs; Immune response; Injections, Intradermal; Injections, Intramuscular; Interleukin 10; Intradermal; Intramuscular; Lesions; Lungs; Male; Modified live virus vaccine; Porcine Reproductive and Respiratory Syndrome - immunology; Porcine Reproductive and Respiratory Syndrome - prevention & control; Porcine reproductive and respiratory syndrome virus; Porcine respiratory and reproductive syndrome virus - classification; Protective efficacy; Spain; Swine; Vaccination; Vaccination - methods; Vaccination - veterinary; Vaccine efficacy; Vaccines; Vaccines, Attenuated - administration & dosage; Vaccines, Attenuated - immunology; Viral Vaccines - administration & dosage; Viral Vaccines - immunology; Viremia; γ-Interferon; Spain; Protective efficacy; Porcine reproductive and respiratory syndrome virus; Immune response; Intradermal; Intramuscular; Modified live virus vaccine; Challenge
• ISSN: 0378-1135; 1873-2542
• DOI: 10.1016/j.vetmic.2020.108655

•Immune response and protective efficacy of PRRSV-1 modified live vaccine (MLV) were investigated.•Intramuscular (IM) and intradermal (ID) administration routes were evaluated.•Protective efficacy of PRRSV-1 MLV was determined using an experimental challenge model.•ID route exhibit an excellent efficacy in immune response and protective efficacy against PRRSV infection. The study was conducted to evaluate the immune response of pigs vaccinated intramuscularly (IM) or intradermally (ID) with porcine reproductive and respiratory syndrome virus 1 (PRRSV-1) modified live vaccine (MLV). The protective efficacy was evaluated upon challenge with highly pathogenic (HP)-PRRSV-2, either alone or in combination with PRRSV-1. Forty-two, castrated male, PRRSV-free pigs were randomly allocated into 7 groups of 6 pig each. IM/HPPRRSV2, IM/CoChallenge, ID/HPPRRSV2 and ID/CoChallenge groups were vaccinated IM or ID with PRRSV-1 MLV (UNISTRAIN® PRRS, Laboratorios Hipra S.A., Amer, Spain) in accordance to the manufacturer’s directions. NV/HPPRRSV2 and NoVac/CoChallenge groups were nonvaccinated/challenged controls. NoVac/NoChallenge group was left as the control. Antibody response, IFN-γ-secreting cells (IFN-γ-SC) and IL-10 production were evaluated following vaccination. At 35 days post vaccination (DPV), all challenged groups were intranasally inoculated with HP-PRRSV-2, either alone or in combination with PRRSV-1. PRRSV viremia and lung lesion scores were evaluated following challenge. The results demonstrated that ID vaccinated pigs had significantly lower IL-10 levels and higher IFN-γ-SC than that of IM vaccinated pigs. Following challenge with HP-PRRSV-2 either alone or with PRRSV-1, PRRSV viremia and lung lesions, both macroscopically and microscopically, were significantly reduced in vaccinated pigs than that of nonvaccinated pigs, regardless to the route of vaccine administration. ID vaccinated pigs had significantly lower levels of PRRSV viremia and lung lesion scores than that of IM vaccinated pigs. The results of the study suggested that the administration of PRRSV-1 MLV, either IM or ID, provided partial protection against HP-PRRSV-2, either alone or when cochallenged with PRRSV-1, as demonstrated by the reduction in lung lesions and viremia. The ID route might represent an alternative to improve vaccine efficacy, as it resulted in lower IL-10 levels and higher IFN-γ-SC levels.