Figure 1.

Gating strategies for the different immune cell subsets (a male pig, aged 18 weeks is shown as a representative animal). In the upper row, identification of monocytes is presented using CD172a and CD163 expression. Below, the gating strategy for the different lymphocyte subpopulations is shown. B cells were determined as CD3^-CD79a⁺. NK cells were characterized as CD3^-CD8α⁺CD16⁺ and further divided into NKp46^-, NKp46⁺, and NKp46^high NK cells. TCR-γδ⁺ T cells can be divided into three phenotypes: CD2^-perforin^- and CD2⁺ cells that can either be negative or positive for perforin expression (no clear CD2^-perforin⁺ γδ⁺ T cells were found). Cytolytic T lymphocytes (CTLs) are defined as CD3⁺CD8β⁺ and can be divided into different phenotypes via their CD27 and perforin expression. CD4 was used as a pan marker for T helper cells and CD8α and CD27 expression can be used to differentiate between naive CD4⁺CD8α^-CD27⁺ (T_Naive) T cells, CD4⁺CD8α⁺CD27⁺ activated and central (T_CM) and CD4⁺CD8α⁺CD27^- effector memory (T_EM) T cells.