Immunomodulatory effects of six Acetobacter pasteurianus strains in RAW-Blue macrophage

In this study, we investigated the immunological properties of six strains of Acetobacter pasteurianus through nuclear factor-kappa B/activator protein-1 (NF-κB/AP-1) transcription factor activation and nitric oxide (NO) and cytokine production in macrophages. We found that the six A. pasteurianus strains had no significant inhibitory effect on the cell viability of RAW-Blue™ cells at the concentration of (25, 50, 100 CFU/macrophage). The production of NO and cytokines (TNF-α, IL-1β, and IL-6) showed different abilities of immune activation for each strain, and it was 0.7 to 0.9 times higher than that of the LPS (100 ng/mL, v/v) positive control and 7 to 8 times superior to that of the negative control group. To explore the underlying mechanism, we evaluated the mRNA expression of pro-inflammatory genes. Consequently, we found that inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 expression including genes expression of cytokines were elevated by the six A. pasteurianus treatment. These results suggested that the six strains of A. pasteurianus have an excellent industrial application value as a functional material for the purpose of enhancing immune function.