Fig. 5: Intestinal luminal arachidonic acid enhances antigen-specific IgA production.

A–D Groups of VRL B6 mice were fed either with a control diet (Ctrl group) or an ARA-supplemented diet (ARA group) [0.4% (v/w)] for 7 days and then intraperitoneally immunized once with OVA mixed with CFA on day 7. The relative levels of serum and cecal content anti-OVA (A and B, n = 10 mice in the Ctrl group and 9 mice in the ARA group) and total (C and D, n = 5 mice/group) IgA were determined on day 21. E Groups of VRL B6 mice were treated daily with vehicle or ARA (20 mg /day) intraperitoneally. On day 7, mice were immunized once with OVA plus CFA. The relative levels of serum anti-OVA IgA were determined on day 21 (n = 4 mice/group). F Schematic of the three major arachidonic acid metabolic pathways. G Schematic of the experimental setup for T.mu colonization or dietary ARA supplementation, selective inhibitors administration, and antigen challenge. H–K The effect of zileuton on the relative levels of serum (H, J) and cecal content (I, K) anti-OVA IgA 14 days post antigen challenge (n = 5 mice/group for Ctrl and Ctrl+Zileuton groups in (H) and (I), n = 9 mice for T.mu group and n = 10 mice for T.mu+Zileuton groups in (H) and (I). n = 6 mice/group in J and K). L, M The effect of aspirin on the relative levels of serum (L) and cecal content (M) anti-OVA IgA 14 days post antigen challenge (n = 5 mice/group). N, O The effect of MS-PPOH on the relative levels of serum (N) and cecal content (O) anti-OVA IgA 14 days post antigen challenge (n = 6 mice/group). All data are shown as mean ± SEM. Two-sided Student’s t-test (A–E) or One-way ANOVA with Tukey’s post hoc test (H–O) were performed. AU arbitrary unit. Source data are provided as a Source Data file.