Specific histamine regulating activity of surface-modified yeast vacuoles by histamine- binding protein and its immune-enhancing effect.

We aimed to develop a biocompatible material that could enhance weakened immunity and control histamine in vivo. Histamine-binding protein (HBP) vacuoles have a mechanism of action that directly binds to the histamine molecule. It is designed to eliminate the side effects of antihistamine caused by binding to other receptors. HBP vacuoles were designed to produce a material that was biocompatible, and could enhance immunity. First, a recombinant vector was designed so that HBP was located on the vacuole surface, and expressed towards the cytoplasm. The vector was transformed into yeast, and protein expression was induced. Then, the vacuole was isolated by centrifugation to complete HBP vacuoles. Cytotoxicity test was conducted for application to RAW 264.7 cells. In addition, immune enhancement reaction and histamine inhibition were confirmed through phagocytosis assay and histamine ELISA. RAW 264.7 cells were pre-treated with HBP vacuoles to confirm the immune enhancement of HBP vacuoles. As a result, it was confirmed that the immunostimulatory effect of the vacuole was increased in a concentration-dependent manner. In addition, the reduction of histamine was confirmed by treating the HBP vacuoles. As a result, HBP vacuoles reduced the histamine secreted from RAW 264.7 cells by about 75%.

Histamine binding activity of surface-modified yeast by histamine binding protein (HBP).

Histamine is an immune mediator that is mainly secreted when an immediate, rapid response is needed in the body, and an excessive secretion of histamine or lack of enzymes that degrade histamine can result in various side effects. Histamine binding protein (HBP) is secreted by a mite species to prevent the host's histamine-induced immune responses by binding the histamine molecule in the blood. Cloning was performed to express HBP on the yeast surface (MBTL-GWL-1), and immunofluorescence (IF) and western blot was performed to confirm the expression of the recombinant protein. The histamine inhibitory ability of GWL-1 cells was tested according to the cell concentration. The highest inhibitory ability of 1.30 × 107 CFU/ml of GWL-1 cells was of about 60 %. The GWL-1 cell concentration and the degree of histamine inhibition were confirmed to be dose-dependent, and dead cell debris was shown to have a histamine inhibitory effect, although not as much as that of whole cells. Phagocytosis assays were performed to determine whether histamine affected the RAW 264.7 cell's phagocytosis, and to indirectly confirm the GWL-1 cell's histamine inhibition. By confirming that, we found that GWL-1 captures histamine. Therefore, it can be expected to become a competitive material in the anti-allergy market.