Aeromonas salmonicida type III secretion system-effectors-mediated immune suppression in rainbow trout (Oncorhynchus mykiss).

Origgi, Francesco; Benedicenti, Ottavia; Segner, Helmut; Sattler, Ursula; Wahli, Thomas; Frey, Joachim (2017). Aeromonas salmonicida type III secretion system-effectors-mediated immune suppression in rainbow trout (Oncorhynchus mykiss). Fish & shellfish immunology, 60, pp. 334-345. Elsevier Science 10.1016/j.fsi.2016.12.006

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Aeromonas salmonicida subsp. salmonicida, the etiologic agent of furunculosis, is a major pathogen in aquaculture. Together with other pathogens, it is characterized by the presence of a type 3 secretion system (T3SS). The T3SS is the main virulence mechanism of A. salmonicida. It is used by the bacterium to secrete and translocate several toxins and effector proteins into the host cell. Some of these factors have a detrimental impact on the integrity of the cell cytoskeleton, likely contributing to impair phagocytosis. Furthermore, it has been suggested that effectors of the T3SS are able to modulate the host's immune response. Here we present the first partial characterization of the immune response in rainbow trout (Oncorhynchus mykiss) infected with distinct strains of A. salmonicida either carrying (i) a fully functional T3SS or (ii) a functionally impaired T3SS or (iii) devoid of T3SS ("cured" strain). Infection with an A. salmonicida strain either carrying a fully functional or a secretion-impaired T3SS was associated with a strong and persistent immune suppression. However, the infection appeared to be fatal only in the presence of a fully functional T3SS. In contrast, the absence of T3SS was neither associated with immune suppression nor fish death. These findings suggest that the T3SS and T3SS-delivered effector molecules and toxins of A. salmonicida do not only impair the host cells' cytoskeleton thus damaging cell physiology and phagocytosis, but also heavily affect the transcription of critical immune mediators including the shut-down of important warning signals to recognize infection and induce immune defense.

Item Type:

Journal Article (Original Article)

Division/Institute:

05 Veterinary Medicine > Research Foci > Host-Pathogen Interaction
05 Veterinary Medicine > Department of Infectious Diseases and Pathobiology (DIP)
05 Veterinary Medicine > Department of Infectious Diseases and Pathobiology (DIP) > Institute of Veterinary Bacteriology
05 Veterinary Medicine > Department of Infectious Diseases and Pathobiology (DIP) > Center for Fish and Wildlife Health (FIWI)

UniBE Contributor:

Origgi, Francesco; Benedicenti, Ottavia; Segner, Helmut; Sattler, Ursula; Wahli, Thomas and Frey, Joachim

Subjects:

600 Technology > 630 Agriculture

ISSN:

1050-4648

Publisher:

Elsevier Science

Language:

English

Submitter:

Lucia Gugger-Raaflaub

Date Deposited:

08 May 2018 12:13

Last Modified:

08 May 2018 12:22

Publisher DOI:

10.1016/j.fsi.2016.12.006

PubMed ID:

27923746

Uncontrolled Keywords:

A. salmonicida Disease Fish Furunculosis Immune suppression Immunity T3SS

BORIS DOI:

10.7892/boris.112099

URI:

https://boris.unibe.ch/id/eprint/112099

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