IFNG and asthma: As shown in (Fig 4), the percentage of IFN-γ+ Th1 cells decreased from 1.32% in PBS group to 0.357% in asthma group and 0.304% in severe asthma group, while intranasal vaccination with recombinant Mycobacterium smegmatis significantly increased IFN-γ+ Th1 cells in spleen.