NK1.1+ innate lymphoid cells in salivary glands inhibit establishment of tissue-resident memory CD8+ T cells in mice

Abstract

NK1.1⁺ cells found in salivary glands (SG) represent a unique cell population of innate lymphoid cells (ILC) with characteristics of both conventional NK cells and ILC1. Here, we demonstrate that these NK1.1⁺ cells limit the accumulation and differentiation of virus-specific tissue-resident memory CD8⁺ T cells (T_RM cells) in SG of mice infected with lymphocytic choriomeningitis virus (LCMV). The negative regulation of LCMV-specific CD8⁺ T_RM cells by NK1.1⁺ cells in SG is independent of NKG2D, NKp46, TRAIL, and perforin. Moreover, analysis of NKp46^iCre+ Eomes^fl/fl mice revealed that Eomes-dependent conventional NK cells are dispensable for negative regulation. Since the SG are prone to autoimmune reactions, regulation of T_RM cells by tissue-resident ILC may be particularly important to prevent immunopathology in this organ.

Keywords: LCMV; innate lymphoid cells; salivary glands; tissue-resident memory T cells.