Plasma 25(OH)D and plasma IL-15 levels were lower in patients with active TB than in LTBI subjects (25(OH)D: 16.64 ng/mL vs. 21.6 ng/mL, P = 0.031; IL-15: 148.9 pg/mL vs. 189.8 pg/mL, P = 0.013).
Novel adjuvant for immunization against tuberculosis: DNA vaccine expressing Mycobacterium tuberculosis antigen 85A and interleukin-15 fusion product elicits strong immune responses in mice.
IL-32 induced the vitamin D-dependent antimicrobial peptides cathelicidin and DEFB4 and to generate antimicrobial activity in vitro, dependent on the presence of adequate 25-hydroxyvitamin D. In addition, the IL-15-induced defense response macrophage gene network was integrated with ranked pairwise comparisons of gene expression from five different clinical data sets of latent compared with active tuberculosis or healthy controls and a coexpression network derived from gene expression in patients with tuberculosis undergoing chemotherapy.
IL-15 acts as a co-stimulator in IFN-γ production by NK cells and may therefore be important in the control of Mycobacterium tuberculosis that requires IFN-γ for clearance.
These findings demonstrate that efficient effector CD4 and CD8 T cells can be developed following M. tuberculosis infection in the absence of IL-15 but that recall T-cell responses may be impaired.
In the present study we have evaluated the expression of IL-15 mRNA and protein in bronchial biopsy specimens obtained from patients with sarcoidosis (n = 8), tuberculosis (n = 7), chronic bronchitis (n = 10), and bronchial asthma (n = 8) and compared its expression with that seen in normal control subjects (n = 11).