Circulating NK cells establish tissue-residency upon acute infection of skin and mediate accelerated effector responses to secondary infection

Natural killer (NK) cells are present in the circulation and can also be found residing in tissues; these populations exhibit distinct developmental requirements and are thought to differ in terms of ontogeny. Here, we investigated whether circulating conventional NK (cNK) cells can develop into long-lived, tissue-resident cells following acute infections. We found that viral and bacterial infections of the skin triggered the recruitment of cNK cells and their differentiation into Tcf1hiCD69hi tissue-resident (trNK) cells that share transcriptional similarity with CD56brightTCF1hi NK cells in human tissues. Skin trNK arose from IFN-g-producing effector cells and required restricted expression of the transcriptional regulator Blimp1 to optimize Tcf1-dependent trNK formation. Upon secondary infection, trNK cells rapidly gained effector function and mediated an accelerated NK cell response. Thus, cNK cells redistribute and permanently position at sites of previous infection via a mechanism promoting tissueresidency that is distinct from Hobit-dependent developmental paths of NK cells and ILC1 seeding tissues during ontogeny Overall design: scRNA-seq, cell hashing and CITE-seq. ILC1s and NK cells were sorted as individual, hash-tagged populations before pooling into one reaction. Before sorting, cells were labeled with oligonucleotide-tagged antibodies for cellular indexing of transcriptomes and epitopes by sequencing (CITE-Seq). List of Hashtags and CITE seq antibody used: Ms.Hashtag_1 ACCCACCAGTAAGAC, Ms.Hashtag_2 GGTCGAGAGCATTCA, Ms.Hashtag_3 CTTGCCGCATGTCAT, Ms.Hashtag_4 AAAGCATTCTTCACG, Ms.Hashtag_5 CTTTGTCTTTGTGAG. HuMs.CD11b TGAAGGCTCATTTGT, Ms.CD45 TGGCTATGGAGCAGA, Ms.CD45.2 CACCGTCATTCAACC, HuMsRt.CD27 CAAGGTATGTCACTG, Ms.CD69 TTGTATTCCGCCATT, Ms.CD127 GTGTGAGGCACTCTT, Ms.CD103 TTCATTAGCCCGCTG, HuMs.KLRG1 GTAGTAGGCTAGACC, Ms.CD49b CGCGTTAGTAGAGTC, Ms.Ly49H CCAGTAGGCTTATTA. We multiplexed Skin d8 with hashtag_1, Skin d25 with hashtag_2, Salivary Gland d25 with hashtag_3, Spleen d8 with hashtag_4, and Spleen d25 with hashtag_5.