CD4+ T-cell gene expression following 980 nm stimulation

Photobiomodulation (PBM) employs red and near-infrared light to modulate biological processes and shows promise in treating inflammatory conditions. Autoimmune colitis involves dysregulated CD4+ T cell responses, with an imbalance between pro-inflammatory effector cells and regulatory T cells (Tregs). Here we applied pulsed 980 nm near-infrared PBM in a murine adoptive transfer model of CD4+ T cell-mediated colitis. PBM treatment reduced disease severity, preserved intestinal barrier function, and reshaped the CD4+ T cell compartment by promoting Treg differentiation and suppressing pro-inflammatory Th1 and Th17 subsets.. Mechanistically, PBM promoted the differentiation of naïve CD4+ T cells into regulatory T cells (Tregs), leading to increased production of the anti-inflammatory cytokine interleukin-10 (IL-10), while concomitantly suppressing pro-inflammatory CD4+ T cell subsets, including TNFα+, IFNγ+ and IL-17A+ CD4+ T cells. Collectively, these findings indicate that PBM exerts potent immunomodulatory effects by restoring the balance between effector and regulatory CD4+ T cell responses, suggesting its potential as a safe, non-pharmacological therapeutic approach for inflammatory bowel disease.