ADAPTIVE NATURAL KILLER (NKA) CELLS FACILITATE EFFECTOR FUNCTIONS OF TRASTUZUMAB IN BREAST CANCER (BC).

BORDIGNON, MARÍA BELÉN; PESCE VIGLIETTI, AYELÉN; JULIÁ, ESTEFANÍA PAULA; MANDÓ, PABLO; SABATINI, LUCIANA; MORDOH, JOSÉ; FAINBOIM, LEONARDO; LEVY, ESTRELLA MARIEL

Congreso; LXIX REUNIÓN ANUAL DE LA SOCIEDAD ARGENTINA DE INMUNOLOGÍA (SAI)-2021; 2021

NK cells have been regarded as primary effectors of innate immunity,but emerging evidence suggests that a subset of these cellshave adaptive immune features, including memory-like properties,such as long-term persistence, robust preferential expansion in responseto viral infection, and enhanced antibody-dependent effectorfunctions. Adaptive NK cell subsets are characterized by a lack ofFcƐRIγ expression and/or high expression of NKG2C.Objective: To identify adaptive NK cell subpopulations in BC patientsand characterize subsets that support robust ex vivo anti-BCactivity via trastuzumab (TRZ)- mediated ADCC.With this aim, we analyzed the immunophenotype of NK cells in peripheralblood samples from our cohort of 60 BC patients and 32healthy donors (HD), both 85% seropositive for human cytomegalovirus.Defining adaptive (NKa) and conventional NK (NKc) cellsas FcRγ- and FcRγ+, respectively, NKa subpopulation was detectedin 66% of BC patients and 75% of HD. We characterized differentialexpression of NK-cell inhibitory and activating receptors.NKa cells expressed significantly higher levels of NKG2C (