New insights in cellular immune response in colostrum-deprived pigs after immunization with subunit and commercial vaccines against Glässer’s disease

Four groups of colostrum-deprived pigs were immunized with Porcilis Glässer® (PG) or with subunit vaccines developed by us (rTbpA, NPAPTM or NPAPTCp) against Glässer’s disease, and they were challenged with 3 × 108 CFU of Haemophilus parasuis. A strong reduction in CD3+γδTCR+ cells was seen in non-immunized control and scarcely protected (rTbpA) groups, suggesting that these cells could represent a target of H. parasuis infection. A significant increase in CD172α+CD163+ cells was detected in all groups but PG, while a reduction in SLAIIDR+ molecules expression was observed after challenge in control animals. Significant increases in CD3ε+CD8α+CD8β+ and B cells were detected respectively in control and NPAPT groups, and in scarcely (rTbpA) and well-protected (NPAPTM and NPAPTCp) groups. Finally, a greater response in CD4+CD8α− cells was observed in NPAPTCp compared to NPAPTM and PG groups. These results state the potential of NPAPT antigen for developing effective vaccines against Glässer’s disease.