Population of PRRSV specific lymphocyte subsets in the blood of pigs. PBMC isolated from individual pigs were unstimulated (control) or stimulated with PRRSV (virus) or pooled five conserved peptides (peptides) and immunostained using indicated pig specific cell surface markers and analyzed by flow cytometry. Population of CD3ε+CD4α−CD8α+, Th/memory cells (CD3ε+CD4α+CD8α+) and γδ T cells in the PBMC collected at 26 dpv (A–C) and 14 dpc (D–F) are shown. Each bar represents the average cell count of 50 000 events from 4 or 5 pigs ± SEM. Lowercase alphabets and asterisks indicate a statistically significant difference (a or *P < 0.05, b or **P < 0.01 and c
P < 0.001) between control (PBS) and vaccine received pig groups under the same ex vivo stimulation condition, or between different stimulation conditions within the same treatment group.