FIG 1.
Activation of innate immune cells by vitamin A metabolites. Primary human monocytes were treated with either vehicle alone (CTRL), retinol (10−8 M), retinaldehyde (ATRH) (10−8 M), or all-trans retinoic acid (ATRA) (10−8 M) for 18 h and the mRNA expression levels of NPC2 (A) and CYP27A1 (B) were measured via qPCR. Data shown are the average fold change (FC) versus CTRL ± standard error of the mean (SEM) (n = 3 to 7). P values by one-way ANOVA. *, P < 0.05; ***, P < 0.001. (C) Black dots represent the serum retinol levels of TB household contact (TB contacts) or active TB patients. The red line indicates the average ± SEM retinol serum levels in each group. P value by Student's t test. ***, P < 0.001.