Gene expression profile of human mono-derived DCs stimulated with the bacterial lysate OM-85

OM-85 is a bacterial lysate used in clinical practice to reduce duration and frequency of recurrent respiratory tract infections. Whereas knowledge on its regulatory effects in vivo has substantially advanced, the mechanisms of OM-85 sensing remain inadequately addressed.The purpose of this study was to investigate the transptomic profile of human mo-DCs after ex vivo stimulation with OM-85 at determine to what extent OM-85-induced gene signature in different myeloid cell subsets is dependent on TLR2/TLR4 expression. We also aimed to compare the OM-85-triggered gene signature with the signatures induced by specific TLR2 or TLR4 agonists. Overall design: To this aimes, mo-DCs were treated with the bacterial lysate OM-85 (100-300-900 ug/ml) for 2-8hr. To investigate the contribution of TLRs in response to OM-85, mo-DCs were pre-treated with isotype control antibody or blocking antibodies agaisnt TLR2 or TLR4 or both for 90 min followed by stimulation with 300 ug/ml OM-85 for 2hr. Cells in parallel were stimulated with 0.1 ng/ml LPS or 10ng/ml Pam3CSK4 for 2hr to compare the TLR2/TLR4 specific gene expression profiles with the one of OM-85.