Abstract

Toll-like receptors (TLRs) are known to detect a defined spectrum of microbial structures. However, the knowledge about the specificity of teleost Tlr factors for distinct pathogens is limited so far. We measured baseline expression profiles of 18 tlr genes and associated signaling factors in four immune-relevant tissues of rainbow trout Oncorhynchus mykiss. Intraperitoneal injection of a lethal dose of Aeromonas salmonicida subsp. salmonicida induced highly increased levels of cytokine mRNAs during a 72-hour postinfection (hpi) period. In contrast, only the fish-specific tlr22a2 and the downstream factor irak1 featured clearly increased transcript levels, while the mRNA concentrations of many other tlr genes decreased. Flow cytometry quantified cell trafficking after infection indicating a dramatic influx of myeloid cells into the peritoneum and a belated low level immigration of lymphoid cells. T and B lymphocytes were differentiated with RT-qPCR revealing that B lymphocytes emigrated from and T lymphocytes immigrated into head kidney. In conclusion, no specific TLR can be singled out as a dominant receptor for A. salmonicida. The recruitment of cellular factors of innate immunity rather than induced expression of pathogen receptors is hence of key importance for mounting a first immune defense against invading A. salmonicida.

Highlights

  • The vertebrate immune system consists of a conserved innate system complemented by a highly specialized immune system

  • T and B lymphocytes were differentiated with RT-qPCR revealing that B lymphocytes emigrated from and T lymphocytes immigrated into head kidney

  • Regarding the tissue-specific expression, we found that all 13 tlr genes were significantly expressed in spleen, head kidney, liver, and thymus (Figure 2(a))

Read more

Summary

Introduction

The vertebrate immune system consists of a conserved innate system complemented by a highly specialized (adaptive) immune system. Both branches of immunity communicate and collaborate in a bipartisan way to ensure the effective destruction of potentially harmful microbes [1]. More than 20 TLRs clustered in six subfamilies have been identified in more than a dozen of fish species [5,6,7] (Figure 1).

Results
Discussion
Conclusion
Full Text
Paper version not known

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.