Levels of neutralizing antibodies against resident farm strain or vaccine strain are not indicators of protection against PRRSV-1 vertical transmission under farm conditions
Martin-Valls, Gerard (Universitat Autònoma de Barcelona. Departament de Sanitat i d'Anatomia Animals)
Li, Yanli (Universitat Autònoma de Barcelona. Departament de Sanitat i d'Anatomia Animals)
Clilverd, Hepzibar (Universitat Autònoma de Barcelona. Departament de Sanitat i d'Anatomia Animals)
Soto, Jordi (Universitat Autònoma de Barcelona. Departament de Sanitat i d'Anatomia Animals)
Cortey, Martí (Universitat Autònoma de Barcelona. Departament de Sanitat i d'Anatomia Animals)
Mateu de Antonio, Enrique María (Universitat Autònoma de Barcelona. Departament de Ciència Animal i dels Aliments)

Date:	2023
Abstract:	Vertical transmission is key for the maintenance of porcine reproductive and respiratory syndrome virus (PRRSV) infection. In vaccinated farms, vertical transmission can still occur despite sows having some level of immunity because of repeated vaccination or contact with the wild-type virus. The present study aimed to correlate the age of sows and the amplitude of neutralizing antibodies (Nab) (heterologous neutralization) with PRRSV-1 vertical transmission (VT). For this purpose, umbilical cords of 1,554 newborns (corresponding to 250 litters) were tested for PRRSV by RT-PCR in two PRRSV-unstable vaccinated farms. In parallel, the sows were bled after farrowing and the levels of antibodies were determined by ELISA and by the viral neutralization test against the vaccine virus, the virus circulating in the farm, and other unrelated contemporary PRRSV-1 strains. The relationship between the parity and the probability of delivering infected piglets and the presence of broadly Nabs examined. The proportion of VT events in the two examined farms ranged from 18. 9% to 23. 0%. Young sows (parity 1-2) were 1. 7 times more likely to have VT than older sows (p < 0. 05). Despite higher ELISA S/P antibody ratios in younger sows (p < 0. 05), NAb against the resident farm strain were at a similar level between sows delivering infected and healthy piglets regardless of age, mostly with low titers (2-3 log). The titers of NAb against the vaccine virus were also low, and no correlations with VT were observed. When a panel of another 4 strains (1 isolated in the 1990s, and 3 contemporary strains) were used for the neutralization test, most sow sera were not capable of neutralizing the contemporary strains. Titers of NAb could not be correlated with the occurrence of PRRSV VT. The amplitude of NAb present in most vaccinated sows is limited with a considerable proportion unresponsive regarding NAb production. The online version contains supplementary material available at 10. 1186/s12917-023-03785-z.
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Porcine reproductive and respiratory virus ; Neutralizing antibodies ; Broadly neutralizing antibodies ; Vertical transmission
Published in:	BMC veterinary research, Vol. 19 (october 2023) , ISSN 1746-6148

DOI: 10.1186/s12917-023-03785-z
PMID: 37858141

7 p, 1.1 MB

The record appears in these collections:
Articles > Research articles
Articles > Published articles