Figure 5: (A) The effect of co-administration of OVA and NIC on the population of Treg-cells. Seven days after the last challenge, splenocytes cultured in RPMI 1640 containing the allergen and 72 h later, the cells were stained with anti-CD4 and anti-Foxp3 antibodies. The population of Treg cells from the OVA-NIC10 group significantly increased compared to the control (*P ≤ 0.05) and OVA (#P ≤ 0.05) groups. The population of Treg cells in the OVA-NIC1 group was more than that detected in the control and OVA groups; however, the difference was insignificant. $ Indicates significant ($P ≤ 0.05) differences between groups. (B-E) The control, OVA, OVA-NIC10, and OVA-NIC1 groups, respectively, indicate the gating strategy and expression of CD4 and Foxp3 in splenocytes of BALB/c mice. FL3 indicated Foxp3 (PE-Cy5) and FL1 specified CD4 (FITC). Data were analyzed with FlowJo software. NIC, Nicotine; OVA, ovalbumin; Ig E, immunoglobulin E; Treg-cell, regulatory T-cell.