Lymph nodes (LNs) contain innate-like lymphocytes that survey the subcapsular sinus (SCS) and associated macrophages for pathogen entry. The factors promoting this surveillance behavior have not been defined. Here we report that IL7RhiCcr6+ lymphocytes in mouse LNs rapidly produce IL17 upon bacterial and fungal challenge. We show that these innate-like lymphocytes are mostly LN resident. Ccr6 is required for their accumulation near the SCS and for efficient IL17 induction. Migration into the SCS intrinsically requires S1pr1 whereas movement from the sinus into the parenchyma involves the integrin LFA1 and its ligand ICAM1. CD169, a sialic acid-binding lectin, helps retain the cells within the sinus, preventing their loss in lymph flow. These findings establish a role for Ccr6 in augmenting innate-like lymphocyte responses to lymph-borne pathogens, and they define requirements for cell movement between parenchyma and SCS in what we speculate is a program of immune surveillance that helps achieve LN barrier immunity.
- Yang Zhang
- Theodore L Roth
- Elizabeth E Gray
- Hsin Chen
- Lauren B Rodda
- Jason G Cyster
- Jason G Cyster
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Animal experimentation: Animals were housed in a specific pathogen-free environment in the Laboratory Animal Research Center at the University of California San Francisco (UCSF), and all experiments conformed to the ethical principles and guidelines approved by the UCSF Institutional and Animal Care and Use Committee, protocol approval number: AN107975-02.
- Ronald N Germain, National Institute of Allergy and Infectious Diseases, United States
© 2016, Zhang et al.
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