CD4 and inflammation: The results showed that IL-28B had no effects on the numbers of T (CD4+, CD8+) cells, B cells, NKT cells γδT cells (Fig. 2A–C) as well as macrophages and Dendritic cells (Fig. S1A,B and D), but significantly increased the number and percentage of NK cells in OVA-challenged lungs (Fig. 2D), suggesting the possible involvement of NK cells in inhibiting OVA-induced airway inflammation.