Figure 2.

Cancer immunosurveillance by tissue-resident lymphocytes. Spontaneous oncogene-driven breast tumors are infiltrated by group 1 innate lymphocytes, conventional, and unconventional T cells. Parabiosis experiments revealed the tissue-resident nature of CD49a- and CD103-co-expressing lymphocytes, including the innate-like T cells (ILTCs), killer innate lymphoid cells (ILCks), and some conventional (Conv.) CD8⁺ T cells. In contrast, natural killer (NK) cells, PD1-expressing conventional CD8⁺ T cells recirculate through blood. Functionally, CD49a⁺CD103⁺ tissue-resident lymphocytes abundantly express lytic granules and can potently lyse transformed target cells. Despite their cytotoxicity, therapies targeting these tissue-resident populations are lacking while rapid advancement has been made to target conventional NK and T cells.