Upregulation of the exhaustion-associated receptor TIM-3 on NK cells requires the cooperation between tumor and accessory cells

MARÍA SOFÍA AMARILLA; ALDANA TROTTA; NATALIA RUBINSZTAIN; BELÉN CANDELA LOZADA MONTANARI; ADRIAN FRIEDRICH; MARIA VICTORIA REGGE; MARÍA CECILIA SANTILLI; MARIANA GANTOV; CAROLINA INES DOMAICA; MERCEDES BEATRIZ FUERTES; NORBERTO WALTER ZWIRNER

San Luis

Congreso; LXXI REUNIÓN CIENTÍFICA ANUAL DE LA SOCIEDAD ARGENTINA DE INMUNOLOGÍA (SAI); 2023

SAI

Immune checkpoint inhibitors have revolutionized immuno-oncology (IO). Recently, natural killer (NK) cells have been positioned at the forefront of IO strategies. However, within the tumor microenvironment (TME), NK usually develop an exhausted phenotype, characterized by an upregulation of NK cell inhibitory checkpoints (NKCIC). For instance, we observed that TIM-3 is upregulated on tumor-infiltrating NK cells from patients with clear cell renal cell carcinoma (ccRCC). Although the blockage of some of these NKCIC results in a reinvigoration of their effector functions, the actual stimuli and mechanisms that induce the expression of NKCIC remain poorly defined. Accordingly, our aim was to elucidate the stimuli that trigger the increased expression of several NKCIC such as TIM-3, LAG-3, TIGIT, PVRIG and PD-1. When NK cells isolated from healthy donors (HD) were stimulated with optimal doses of IL-15, a cytokine that promotes NK cell survival and proliferation, for short (2 d) or long (14 d) periods, we did not observe appreciable changes in the frequency of NK cells (CD3-CD56+) expressing NKCIC, evaluated by flow cytometry. We also didn´t observe appreciable changes when isolated NK cells from HD were cultured with an ccRCC cell line (786-O) for 2 d or 5 d. However, when peripheral blood mononuclear cells (PBMC) from HD were cultured with 786-O cells for 2 d, a significant increase in the frequency of TIM-3+ NK cells was observed (Mean ± SD, NK: 19,0 ± 17,4 vs NK+786-O: 53,3 ±14,3, p