Induction of β-defensin 2 (HBD-2) in human middle ear epithelial cells (HMEEC-1) using various NTHi preparations or NTHi variants. With the exception of lipoolygosaccharide (LOS), all other NTHi preparations were derived from the same colony of NTHi strain 12. The LOS was purified from NTHi 12 and used at a concentration of 500 ng/ml. Live NTHi12 was treated using an multiplicity of infection (MOI) of 100 and NTHi WCL (whole cell lysate) and P (Pellet) were used at a concentration of 5 μg/ml. (A), The WCL treatment induced substantially higher expression of HBD-2 than other preparations. (B), Different strains of NTHi WCL were prepared and treated at the same concentration (5 μg/ml). The induction of HBD-2 mRNA was not significantly different between the tested strains. Values are given as mean ± standard deviation. N = 3. *: p < 0.05.