Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 15 4 2023 08 27 557 564 Melika Khanzadeh Tehrani Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Mohammad Hossein Yazdi Recombinant Vaccine Research Center, Tehran University of Medical Sciences, Tehran, Iran Mohammad Reza Pourmand Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran; Biotechnology Research Center, Tehran University of Medical Sciences, Tehran, Iran 2023 04 23 2023 08 06 Background and Objectives: The increasing number of methicillin-resistant Staphylococcus aureus persuade the need for preventive measures. Glucomannan is a polysaccharide choice for developing immunological strategies. This study aimed to investigate changes in gene expression and phagocytic activity of macrophage cells in the presence of glucomannan. Materials and Methods: The effect of different concentrations of glucomannan (25, 50, and 100 µg/mL) on the phagocytic activity of macrophage cells was measured using the colony count method. The expression of Tumor Necrosis Factor-alpha (TNF-α) and Inducible Nitric Oxide Synthase (iNOS) genes was evaluated by Real-Time PCR. Results: The concentrations of glucomannan significantly reduced the bacterial Colony-Forming Unit (CFU) and increased the phagocytic activity of macrophage cells. The maximum effect of glucomannan on iNOS and TNF-Α genes expression was 100 µg/mL. Conclusion: Glucomannan should be considered an adjuvant that stimulates the immune system. It may increase the expression of TNF-α and iNOS genes and the phagocytic activity of macrophage cells against methicillin-resistant Staphylococcus aureus. https://ijm.tums.ac.ir/index.php/ijm/article/view/4199 https://ijm.tums.ac.ir/index.php/ijm/article/download/4199/1600