Analysis of susceptibility to bacterial secondary infection associated with influenza virus infection and establishment of preventive methods

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K08846
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 54030:Infectious disease medicine-related
• Research Institution: Showa University
• Principal Investigator: Ishikawa Hiroki 昭和大学, 医学部, 准教授 (60433918)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: インフルエンザウイルス / 細菌二次感染

Outline of Final Research Achievements

In this study, we investigated in vitro the mechanism of susceptibility to bacterial secondary infection caused by influenza virus infection and methods for its prevention. As a result, influenza virus infection increased the expression level of the CEACAM-1 molecule gene, which bacteria use for adhesion to cells, and actually increased the number of bacteria adhering to cells. It was also confirmed that influenza virus infection reduces the expression level of ZO-1 gene, one of the components of tight junctions, and actually causes a decline in epithelial barrier function. In response to these effects, polysaccharides produced by lactic acid bacteria suppressed viral infection, and an associated decrease in CEACAM-1 gene expression and recovery of ZO-1 gene expression were observed.

Free Research Field

微生物学　免疫学

Academic Significance and Societal Importance of the Research Achievements

インフルエンザウイルス感染に続く、細菌二次感染は宿主病態悪化の危険因子のひとつである。本研究ではインフルエンザウイルス感染よる細菌二次感染易感染性はウイルス感染細胞の細菌接着分子遺伝子発現誘導およびタイトジャンクション遺伝子発現低下による上皮バリア機能脆弱により起こる可能性を示唆した。また予防法として乳酸菌産生多糖体がインフルエンザウイルス感染予防効果を示し、それに伴う易感染性のメカニズムも改善することが認められた。インフルエンザウイルス感染予防に乳酸菌産生多糖体が効果を持つことを論文として情報を発信した。