T cells drive vaccine effectiveness against porcine reproductive and respiratory syndrome virus

A study published in the journal Vaccine has found that T cell responses, rather than antibody production, play a significant role in the effectiveness of vaccines against the porcine reproductive and respiratory syndrome virus (PRRSV). The research, led by Michael Rahe from North Carolina State University, highlights the challenges posed by PRRSV, which is known for its rapid mutations and is responsible for over $1 billion in losses annually to the pork industry.

The research evaluated four groups of pigs: one unvaccinated and unchallenged, one unvaccinated but challenged with PRRSV, one vaccinated with a commonly used PRRSV vaccine and challenged, and one vaccinated with a combination vaccine for PRRSV and porcine circovirus 2, followed by a challenge. The findings revealed that vaccinated pigs exhibited increased T cell responses and reduced viral levels, indicating partial protection despite a lack of neutralizing antibodies.

Understanding the immune response facilitated by T cells is crucial, given the mismatch between neutralizing antibodies and circulating virus strains. Rahe’s research underscores the need for future vaccines to target specific conserved elements of the virus, which could lead to more effective immunization strategies.

The study received support from Boehringer Ingelheim Animal Health, Inc., with several contributors from both North Carolina State and Iowa State University.