PMID- 19442420
OWN - NLM
STAT- MEDLINE
DCOM- 20090831
LR  - 20220330
IS  - 1873-2518 (Electronic)
IS  - 0264-410X (Linking)
VI  - 27
IP  - 28
DP  - 2009 Jun 8
TI  - Efficacy of a modified live porcine reproductive and respiratory syndrome virus 
      (PRRSV) vaccine in pigs naturally exposed to a heterologous European (Italian 
      cluster) field strain: Clinical protection and cell-mediated immunity.
PG  - 3788-99
LID - 10.1016/j.vaccine.2009.03.028 [doi]
AB  - The purpose of this study was to assess clinical protection in pigs vaccinated 
      with a commercially available attenuated porcine reproductive and respiratory 
      syndrome virus (PRRSV) vaccine (Porcilis) PRRS) and then naturally exposed under 
      field conditions to a heterologous (Italian cluster) strain of virulent PRRSV. A 
      total of 30, 4-week-old pigs seronegative for PRRSV were allocated to 1 of 3 
      groups (IM, ID, and C groups). At 5 weeks of age, pigs of groups IM (n=10 pigs) 
      and ID (n=10 pigs) were vaccinated intramuscularly and intradermally, 
      respectively, with modified live PRRSV-1 vaccine (Porcilis) PRRS). Pigs of group 
      C (n=10 pigs) were kept as non-vaccinated controls. At post-vaccination (PV) days 
      0, 7, 14, 28, and 45, blood samples were collected for detection of vaccine virus 
      (PCR) and antibody response (ELISA), identification of changes in lymphocyte 
      subpopulations by cytometry, and IFN-gamma PRRSV-specific secreting cells (SC) by 
      ELISpot. At PV day 45, pigs of A, B, and C groups were moved to a site 3 
      conventional finishing herd with a history of respiratory disease caused by PRRSV 
      and the most common bacteria to be exposed to a natural challenge. The PRRSV 
      field strain, belonging to the Italian cluster of the PRRSV-1, demonstrated a 84% 
      identity with the vaccine virus (DV strain) at ORF5 sequencing. At 0 (exposure 
      day=45 days PV), 4, 7, 11, 14, 19, 21, 28, and 34 days post-exposure (PE) blood 
      samples were collected for detection and titration of PRRSV and antibody, as well 
      as for lymphocyte and IFN-gamma measurement as described above. Throughout the 
      post-exposure period, all pigs were observed daily for clinical signs. The 
      overall clinical signs were reduced by 68 and 72%, respectively in the 
      intramuscularly and intradermally vaccinated pigs compared to controls. 
      Respiratory signs were reduced by 72 and 80%, respectively in the IM and ID 
      groups. Clinical protection was associated with marked activation of 
      cell-mediated immune response. The highest levels of specific IFN-gamma 
      production at 21-34 days PE were concomitant and associated to changes in natural 
      killer (NK) cells, gamma/delta T, and cytotoxic T lymphocytes in the blood. In 
      our field study, evidences of EU attenuated vaccine-induced clinical protection 
      against natural exposure to a genetically diverse (84% homology) PRRSV-1 isolate 
      (Italian cluster) was demonstrated by the statistically significant reduction in 
      clinical signs in terms of incidence, duration and severity and by a more 
      efficient cell-mediated immune response in the vaccinated pigs as compared to the 
      unvaccinated controls.
FAU - Martelli, Paolo
AU  - Martelli P
AD  - Department of Animal Health, University of Parma, Via del Taglio, 10, 43126 
      Parma, Italy. paolo.martelli@unipr.it
FAU - Gozio, Stefano
AU  - Gozio S
FAU - Ferrari, Luca
AU  - Ferrari L
FAU - Rosina, Stefano
AU  - Rosina S
FAU - De Angelis, Elena
AU  - De Angelis E
FAU - Quintavalla, Cecilia
AU  - Quintavalla C
FAU - Bottarelli, Ezio
AU  - Bottarelli E
FAU - Borghetti, Paolo
AU  - Borghetti P
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20090403
PL  - Netherlands
TA  - Vaccine
JT  - Vaccine
JID - 8406899
RN  - 0 (Antibodies, Viral)
RN  - 0 (Vaccines, Attenuated)
RN  - 0 (Viral Vaccines)
RN  - 82115-62-6 (Interferon-gamma)
SB  - IM
MH  - Animals
MH  - Antibodies, Viral/blood
MH  - Injections, Intradermal
MH  - Injections, Intramuscular
MH  - Interferon-gamma/metabolism
MH  - Italy
MH  - Leukocytes, Mononuclear/immunology
MH  - Porcine Reproductive and Respiratory Syndrome/immunology/*prevention & control
MH  - Porcine respiratory and reproductive syndrome virus/*immunology
MH  - Severity of Illness Index
MH  - Swine
MH  - Vaccines, Attenuated/administration & dosage/immunology
MH  - Viral Vaccines/administration & dosage/*immunology
MH  - Viremia
EDAT- 2009/05/16 09:00
MHDA- 2009/09/01 06:00
CRDT- 2009/05/16 09:00
PHST- 2008/10/27 00:00 [received]
PHST- 2009/02/10 00:00 [revised]
PHST- 2009/03/16 00:00 [accepted]
PHST- 2009/05/16 09:00 [entrez]
PHST- 2009/05/16 09:00 [pubmed]
PHST- 2009/09/01 06:00 [medline]
AID - S0264-410X(09)00434-4 [pii]
AID - 10.1016/j.vaccine.2009.03.028 [doi]
PST - ppublish
SO  - Vaccine. 2009 Jun 8;27(28):3788-99. doi: 10.1016/j.vaccine.2009.03.028. Epub 2009 
      Apr 3.