PCV2 vaccination induces IFN-γ/TNF-α co-producing T cells with a potential role in protection

In this study we analysed antigen-specific T cell responses against PCV2 in a controlled vaccination and infection experiment. We focused on the ability of CD4+ T cells to produce cytokines using multicolour flow cytometry (FCM). Vaccination with a PCV2 subunit vaccine (Ingelvac CircoFLEX®) induced PCV2-specific antibodies only in five out of 12 animals. Conversely, vaccine-antigen specific CD4+ T cells which simultaneously produced IFN-γ and TNF-α and had a phenotype of central and effector memory T cells were detected in all vaccinated piglets. After challenge, seroconversion occurred earlier in vaccinated and infected pigs compared to the non-vaccinated, infected group. Vaccinated pigs were fully protected against viremia after subsequent challenge. Therefore, our data suggests that the induction of IFN-γ/TNF-α co-producing T cells by PCV2 vaccination may serve as a potential correlate of protection for this type of vaccine.
Source: Veterinary Research - Category: Veterinary Research Source Type: research