Ability of ELISAs to detect antibodies against porcine respiratory and reproductive syndrome virus in serum of pigs after inactivated vaccination and subsequent challenge

Abstract

BackgroundIn this study, six enzyme-linked immunosorbent assays (ELISA), intended for routine porcine reproductive and respiratory syndrome virus (PRRSV) herd monitoring, are tested for their ability to detect PRRSV specific antibodies in the serum of pigs after vaccination with an inactivated PRRSV type 1 vaccine and subsequent infection with a highly pathogenic (HP) PRRSV field strain. For this reason, ten piglets (group V) from a PRRSV negative herd were vaccinated twice at the age of 2 and 4 weeks with an inactivated PRRSV vaccine. Ten additional piglets (group N) from the same herd remained unvaccinated. Three weeks after second vaccination, each of the piglets received an intradermal application of an HP PRRSV field strain. Serum samples were taken before first vaccination as well as before and 3, 7, 10 and 14 days after HP PRRSV application. All serum samples were tested for PRRSV RNA by reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) as well as for PRRSV antibodies with all six study ELISAs.ResultsAt the beginning of the study (before vaccination), all of the piglets were PRRSV antibody negative with all study ELISAs. They also tested negative for PRRSV RNA measured by RT-qPCR. From day 3 after HP PRRSV application until the end of the study, a viremia was detected by RT-qPCR in all of the piglets. On day 0 (day of HP PRRSV application), nine out of ten piglets of the pre-vaccinated group tested PRRSV antibody positive with one of the tested ELISAs, although with lower S/P values than after infection. On day 10 after HP PRRSV application, all study ELISAs except one had significantly higher S/P or OD values, respectively more positive samples, in group V than in group N.ConclusionsOnly one of the tested ELISAs was able to detect reliably PRRSV antibodies in pigs vaccinated with an inactivated PRRSV vaccine. With most of the tested ELISAs, higher S/P values respectively more positive samples after PRRSV infection were seen in the pre-vaccinated group than in the non-vaccinated.

Dynamics and Differences in Systemic and Local Immune Responses After Vaccination With Inactivated and Live Commercial Vaccines and Subsequent Subclinical Infection With PRRS Virus

“…There are only a few papers published providing a comprehensive picture of immune response after vaccination against PRRSV (40)(41)(42)(43) because the majority of the existing studies are based mainly on the evaluation of the vaccination effectiveness by monitoring the immune responses found in the blood (5,30,33,(44)(45)(46). Our results show that antibodies after immunization and infection, and the virus after infection, can be detected in all the monitored compartments (blood, respiratory tract, intestine).…”

Skin-Based Vaccination: A Systematic Mapping Review of the Types of Vaccines and Methods Used and Immunity and Protection Elicited in Pigs

“…While there is no specific platform that stands out for the intradermal route, 83% of epidermal vaccinations use DNA platforms. Some of the studies evaluated the combination of the skin-based route of administration with intramuscular, oral, subcutaneous, or intranasal, simultaneously [ 112 , 132 ] or through heterologous prime-boost regimens using the same or different vaccines [ 111 , 122 , 142 , 147 , 150 , 202 , 206 , 208 , 217 , 223 , 229 , 234 , 238 , 261 ], with the objective to elicit a stronger immune response.…”

An intercomparison study of ELISAs for the detection of porcine reproductive and respiratory syndrome virus – evaluating six conditionally dependent tests

“…In a previous investigation, we showed that the applied iterative frequentist approach of the LCA needs well-chosen starting values to converge to the true underlying values [25]. Therefore, we used three sources of information for the parameters required: the manufacturers' evaluation studies conducted for every commercially available test, previous publications evaluating the diagnostic tests used in this study [7,[27][28][29][30][31][32][33][34] and experience from application from the researchers of the Bavarian Animal Health Service. Additionally, we used the examined dataset to estimate the prevalence in the sample.…”