Vitamin D3 and the Importance of IL-15

Here's another interesting area to keep an eye on, namely the apparent importance of IL-15 for bioconversion of 5-hydroxyvitamin D3 (25D3) into bioactive 1,25D3 and the downstream induction of cathelicidins:

"In this study, we found that TLR2/1-induced IL-15 was required for induction of CYP27b1, the VDR and the downstream antimicrobial peptide cathelicidin.  Although both IL-15 and IL-4 triggered macrophage differentiation, only IL-15 was sufficient by itself to induce CYP27b1 and subsequent bioconversion of 25-hydroxyvitamin D3 (25D3) into bioactive 1,25D3, leading to VDR activation and induction of cathelicidin"

Here's another study along these lines:

"Together, these results demonstrate that IL-15 plays an important role in antigen-induced neutrophil migration during inflammationi<i<, triggering a sequential OVA, IL-15, IL-18, MIP-2, MIP-1alpha, TNF-alpha, LTB4 and neutrophil migration signaling cascade"


There are quite a few other studies in pubmed showing the importance of IL-15 in fighting infectionsi<i<.  Here are a couple:

Unfortunately, some drugs seem to inhibit IL-15, and researchers are on the hunt for additional IL-15 inhibitors to treat "inflammatory" diseasesi<i<: