Phenotypic and functional characterization of memory Natural Killer (NKm) cells in patients with Breast Cancer (BC)

JULIÁ, ESTEFANÍA PAULA; BORDIGNON, MARÍA BELÉN ; PESCE VIGLIETTI, AYELÉN ; SABATINI, LUCIANA; COLÓ, FEDERICO; MANDÓ, PABLO; LEVY, ESTRELLA M.

Congreso; BUENOS AIRES BREAST CANCER SYMPOSIUM, BA-BCS 2021; 2021

Memory-like NK (NKm) cells, present in individualsseropositive for cytomegalovirus (HCMV+), exhibitcharacteristics to be exploited in monoclonal antibody(MAb)-therapy directed against tumor antigens, mainlytheir amplified production of cytokines and proliferationin response to stimulation through CD16 receptors. Weaimed to evaluate in vitro the functionality of NKm cellsagainst Triple-Negative Breast Cancer (TNBC) cells opsonizedwith IgG1 isotype MAbs. Peripheral blood sampleswere obtained from healthy donors (HD; n = 16) and BCpatients (n = 25) without prior treatment, at the time ofprimary tumor surgery. The proportion of individuals seropositivefor HCMV+ was similar in BC patients and HD(84% vs. 81%, respectively). We determined two NK cellsubpopulations based on their expression of FcεRIγ byFACS: FcεRIγ negative -NKγ¯- (memory) and NKγ+ (conventional).BC patients presented a NKγ¯ subpopulationin about half of the HCMV+ individuals with phenotypiccharacteristics similar to those previously described inthese cells in HD: lower expression of NKp30 and CD161,and higher of NKG2C and CD85j, with respect to NKγ+cells. Then, we performed functional assays. In HD, NKγ¯cells showed a higher production of IFN-γ (p