Thesis or Dissertation Streptococcus pyogenes CAMP factor attenuates phagocytic activity of RAW 264.7 cells.

Kurosawa, Mie  ,  黒澤, 美絵

2016-03-23 , 新潟大学
学位の種類: 博士(歯学). 報告番号: 甲第4139号. 学位記番号: 新大院博(歯)甲第337号. 学位授与年月日: 平成28年3月23日
Microbes and Infection. 2016, 18(2), 118-127.
Streptococcus pyogenes produces molecules that inhibit the function of human immune system, thus allowing the pathogen to grow and spread in tissues. It is known that S. pyogenes CAMP factor increases erythrocytosis induced by Staphylococcus aureus b-hemolysin. However, the effects of CAMP factor for immune cells are unclear. In this study, we investigated the effects of CAMP factor to macrophages. Western blotting analysis demonstrated that all examined strains expressed CAMP factor protein. In the presence of calcium or magnesium ion, CAMP factor was significantly released in the supernatant. In addition, both culture supernatant from S. pyogenes strain SSI-9 and recombinant CAMP factor dose-dependently induced vacuolation in RAW 264.7 cells, but the culture supernatant from Dcfa isogenic mutant strain did not. CAMP factor formed oligomers in RAW 264.7 cells in a time-dependent manner. CAMP factor suppressed cell proliferation via G2 phase cell cycle arrest without inducing cell death. Furthermore, CAMP factor reduced the uptake of S. pyogenes and phagocytic activity indicator by RAW 264.7 cells. These results suggest that CAMP factor works as a macrophage dysfunction factor. Therefore, we conclude that CAMP factor allows S. pyogenes to escape the host immune system, and contribute to the spread of streptococcal infection.

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