@article{kick_wolfe_amaral_cortes_almond_crisci_gauger_pittman_kaeser_2021, title={Maternal Autogenous Inactivated Virus Vaccination Boosts Immunity to PRRSV in Piglets}, volume={9}, ISSN={["2076-393X"]}, url={https://doi.org/10.3390/vaccines9020106}, DOI={10.3390/vaccines9020106}, abstractNote={Maternal-derived immunity is a critical component for the survival and success of offspring in pigs to protect from circulating pathogens such as Type 2 Porcine Reproductive and Respiratory Syndrome Virus (PRRSV-2). The purpose of this study is to investigate the transfer of anti-PRRSV immunity to piglets from gilts that received modified-live virus (MLV) alone (treatment (TRT) 0), or in combination with one of two autogenous inactivated vaccines (AIVs, TRT 1+2). Piglets from these gilts were challenged with the autogenous PRRSV-2 strain at two weeks of age and their adaptive immune response (IR) was evaluated until 4 weeks post inoculation (wpi). The systemic humoral and cellular IR was analyzed in the pre-farrow gilts, and in piglets, pre-inoculation, and at 2 and 4 wpi. Both AIVs partially protected the piglets with reduced lung pathology and increased weight gain; TRT 1 also lowered piglet viremia, best explained by the AIV-induced production of neutralizing antibodies in gilts and their transfer to the piglets. In piglets, pre-inoculation, the main systemic IFN-γ producers were CD21α+ B cells. From 0 to 4 wpi, the role of these B cells declined and CD4 T cells became the primary systemic IFN-γ producers. In the lungs, CD8 T cells were the primary and CD4 T cells were the secondary IFN-γ producers, including a novel subset of porcine CD8α−CCR7− CD4 T cells, potentially terminally differentiated CD4 TEMRA cells. In summary, this study demonstrates that maternal AIV vaccination can improve protection of pre-weaning piglets against PRRSV-2; it shows the importance of transferring neutralizing antibodies to piglets, and it introduces two novel immune cell subsets in pigs—IFN-γ producing CD21α+ B cells and CD8α−CCR7− CD4 T cells.}, number={2}, journal={VACCINES}, publisher={MDPI AG}, author={Kick, Andrew R. and Wolfe, Zoe C. and Amaral, Amanda E. and Cortes, Lizette M. and Almond, Glen W. and Crisci, Elisa and Gauger, Phillip C. and Pittman, Jeremy and Kaeser, Tobias}, year={2021}, month={Feb} }