Immunological properties and functions of phagocytic B cells

2015 Fiscal Year Final Research Report

• Project/Area Number: 26893328
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Single-year Grants
• Research Field: Experimental pathology
• Research Institution: National Defense Medical College
• Principal Investigator: NAKASHIMA Masahiro 防衛医科大学校(医学教育部医学科進学課程及び専門課程、動物実験施設、共同利用研究, その他部局等, 助教 (70738103)
• Research Collaborator: Seki Shuhji 防衛医科大学校, 医学教育部医学科専門課程, 教授 (80531392) ; Nakanishi Kuniaki 防衛医科大学校, 病院, 教授 (60523115) ; Shinomiya Nariyoshi 防衛医科大学校, 医学教育部医学科専門課程, 教授 (40505260)
• Project Period (FY): 2014-08-29 – 2016-03-31
• Keywords: B細胞 / 貪食 / 獲得免疫 / 莢膜多糖類 / 肺炎球菌表面タンパク

Outline of Final Research Achievements

We have previously reported that mammalian B cells could phagocytose bacterial pathogen although their physiological functions have not been clarified. The present research was aimed at elucidating their functions in the host defense against bacterial infection, especially focused on the acquired immune responses, mainly by sorting B cells positive for pHrodo- or FITC-labeled Streptococcus pneumoniae. Phagocytic B cells not only produced IgM specific for pneumonoccal polysaccharide (anti-PPS IgM) by themselves, but also induced transferred mouse to produce IgG specific for pneumococcal surface protein A (anti-PspA IgG). When transferred with sufficient number of B cells positive for FITC-labeled bacteria, they acquired resistance to fatal dose of bacteria with intravenous injection.
These findings suggest that phagocytic B cells themselves produce anti-PPS IgM, while they would initiate acquired immune responses as antigen presenting cells likewise other phagocytic cells.

Free Research Field

免疫学