Defense of zebrafish embryos against Streptococcus pneumoniae infection is dependent on the phagocytic activity of leukocytes

详细信息    查看全文

• 作者：Samuli  ; Rounioja^a ;   ; ^b ;   ; ^{samuli.rounioja@uta.fi} ; Anni  ; Saralahti^a ; Lilli  ; Rantala^a ; Mataleena  ; Parikka^a ; Birgitta  ; Henriques-Normark^d ; Olli  ; Silvennoinen^a ;   ; ^b ; Mika  ; Rä ; met^a ;   ; ^c
• 关键词：Zebrafish ; Streptococcus pneumoniae ; Innate immunity ; Host&ndash ; pathogens interactions
• 刊名：Developmental and Comparative Immunology
• 出版年：2012
• 出版时间：February 2012
• 年：2012
• 卷：36
• 期：2
• 页码：342-348
• 全文大小：621 K

文摘

Severe community acquired pneumonia caused by Streptococcus pneumoniae is the most common cause of death from infection in developing countries. Serotype specific conjugate vaccines have decreased the incidence of invasive infections, but at the same time, disease due to non-vaccine serotypes have increased. New insights into host immune mechanisms against pneumococcus may provide better treatment and prevention strategies. Zebrafish is an attractive vertebrate model for studying host immune responses and infection biology. Here we show that an intravenous challenge with pneumococcus infects zebrafish embryos leading to death in a dose dependent manner. Survival rates correlate with the bacterial burden in the embryos. The production of proinflammatory cytokines is induced in zebrafish after pneumococcal exposure. Importantly, morpholino treated embryos lacking either myeloid cells or the ability to phagocytose bacteria have lowered survival rates compared to wild type embryos after pneumococcal challenge. These data suggest that the survival of zebrafish embryos upon intravenous infection with S. pneumoniae is dependent on the clearance of the bacteria by phagocytosing cells. Additionally, we demonstrate that mutant pneumococci lacking known virulence factors are attenuated in the zebrafish model. Our data demonstrate that zebrafish embryos can be used for study innate immune responses as well as virulence determinants in pneumococcal infections.