Acetylcholine stored in dendritic cells plays a role in the differentiation of naïve CD 4 + T cells into a Th1 phenotype

Objective Immune cells, particularly dendritic cells ( DC ), express choline acetyltransferase, an enzyme essential for the production of acetylcholine ( AC h); thus, DC appear to store AC h. However, the immunological role of intracytoplasmic AC h within DC is largely unknown. Methods To examine the role of AC h during adaptive responses, naïve CD 4 + T cells were stimulated with anti‐ CD 3 and anti‐ CD 28 antibodies in the presence or absence of AC h. Next, monocyte‐derived DC (Mo‐ DC ) were stained with an anti‐ AC h antibody to investigate the intracytoplasmic storage of AC h. Results The results showed that Mo‐ DC stored AC h in the intracytoplasmic space. Stimulation with lipopolysaccharide (a Th1‐inducing agent) increased the levels of AC h in Mo‐ DC ; however, levels decreased under conditions that mimicked the interaction between DC and naïve CD 4 + T cells. Interferon‐γ secretion increased preferentially in the presence of AC h, suggesting that naïve CD 4 + T cells differentiate into T helper (Th)1 cells in the presence of AC h. Conclusions These observations suggest that Mo‐ DC increase AC h storage in the presence of a Th1 adjuvant and release it during the interaction between DC and naïve CD 4 + T cells, thereby driving their differentiation into Th1 cells. Thus, DC might utilize AC h to regulate the Th1 population in response to certain antigens.