Vitamin D is a key component in a critical signaling pathway in T immune cells, according to a study published online in Nature Immunology. The finding explains why T cells from patients with low concentrations of vitamin D are less fit during infection compared to T cells from healthy individuals.
Carsten Geisler and colleagues found that 'inexperienced' or naive human T cells lack the expression of PLC-gamma1 ― an enzyme required for signaling in T cells. The lack of this enzyme makes naive T cells much less responsive to antigen stimulation than 'experienced' or mature T cells. PLC-gamma1 expression was found to require vitamin D. Strikingly, the dependency of mature T cells on vitamin D was not found in mice.