# Evaluation of Different DNA Vaccines against Porcine Reproductive and Respiratory Syndrome (PRRS) in Pigs

## TL;DR

This study tested five DNA vaccines against PRRS in pigs and found that while none fully protected against the virus, some reduced symptoms and triggered immune responses.

## Contribution

The study evaluates the immune responses and efficacy of five different DNA vaccines against PRRS in pigs.

## Key findings

- Vaccines A and B reduced clinical signs of PRRS infection.
- ELISA IgM was detected 30 days after vaccination with A or B, and IgG was detected 90 days after vaccination with B or C.
- Vaccine C induced IFN-γ 90 days post-vaccination and increased after challenge.

## Abstract

In veterinary medicine, there have been different experiences with the plasmid DNA vaccination. In this area and with the hypothesis to demonstrate the effectiveness of different plasmids encoding porcine respiratory and reproductive syndrome (PRRS), five DNA vaccines against PRRS were evaluated for their innocuity and efficacy in pigs. Eighteen animals were divided into five groups which were injected with five (A, B, C, D, E) different DNA vaccines. Albeit, none of the proposed vaccines were able to protect the animals against PRRS virus. Only vaccines A and B were able to reduce the clinical signs of the infection. ELISA IgM were detected 30 days after the first vaccination in the pigs injected by Vaccine A or B. ELISA IgG were detected 90 days after the first vaccination in the pigs injected by Vaccine B or C. Neutralizing antibody were detected Post Challenge Days 61 (PCD) in all groups. In the pigs inoculated with Vaccine C, IFN-γ were detected 90 days after first vaccination, and after challenge exposure they increased. In the other groups, the IFN-γ were detected after challenge infection. Pigs injected with each of the vaccines A, B, C, D and E showed a significantly higher level of CD4−CD8+ lymphocytes (p < 0.001) after infection in comparison with their controls.