Researchers from The Pirbright Institute have developed new tools to identify and study a critical group of immune cells in pigs that help generate protective antibodies following vaccination and infection.
The breakthrough is an important step in using pigs as a model for vaccine development and could help accelerate the design and evaluation of vaccines for both animal and human health. Published in the Journal of Immunology, the study focuses on T follicular helper (Tfh) cells - specialised immune cells that play a central role in helping B cells produce high-quality antibodies.
Essential for long-lasting immunity, the cells are increasingly recognised as one of the most important indicators of successful vaccine responses. While Tfh cells have been extensively studied in humans and mice, little was known about their counterparts in pigs, despite pigs being widely used as a preclinical model for infectious disease and vaccine research.
A major challenge for researchers has been the lack of tools needed to identify and analyse porcine Tfh cells. To overcome this, the team developed a new antibody that targets CXCR5, a hallmark marker of Tfh cells, alongside a novel reagent capable of detecting PD-1, another key molecule associated with these cells.
Using these tools, scientists successfully identified several distinct populations of Tfh cells and their regulatory counterparts, known as T follicular regulatory (Tfr) cells, in blood, lymph nodes, spleen and tonsils from healthy pigs.
Co-author and senior postdoctoral scientist, Dr Jane Edwards, said: “Our study revealed that pig Tfh and Tfr cells share many of the same characteristics seen in humans and mice, highlighting important similarities between species and reinforcing the value of pigs as a model for understanding vaccine-induced immunity.”
The researchers found that tonsils harboured significantly more Tfh cells than other lymphoid organs examined, suggesting that the tonsils are a key site for generating antibody responses. In contrast, neighbouring lymph nodes contained relatively higher numbers of regulatory Tfr cells, which help control immune responses and prevent harmful autoimmunity. This balance between helper and regulatory cells may provide important clues about how immune responses are naturally controlled at sites where pathogens frequently enter the body.
To determine whether the newly identified porcine Tfh cells functioned as expected, the researchers carried out laboratory experiments combining Tfh cells with B cells. The findings demonstrated that Tfh and germinal centre Tfh cells were highly effective at supporting B cell survival, proliferation and differentiation into antibody-producing plasma cells, confirming their critical role in driving humoral immunity.
The ability to identify and monitor these cells could improve the evaluation of vaccine candidates against a range of viral and bacterial diseases. It may also help scientists better understand how vaccines stimulate protective immunity and why some vaccines generate more durable responses than others. The researchers believe the work will strengthen the immunological toolkit available for pig studies and support future investigations into both veterinary and human vaccines.
- Zaki D, Schmidt S, Wells J, et al. Phenotypic and functional characterization of porcine T follicular helper and regulatory cells. J Immunol. 2026;215(10):vkag264. doi:10.1093/jimmun/vkag264