FCGR3A and neoplasm: To assess functional activation, surface CD69 expression—an early activation marker—was quantified on T cells (gated as CD3+ lymphocytes) and NK cells (gated as CD16+ lymphocytes) in PBMC-tumor co-culture systems using multiparameter staining with anti-CD3/anti-CD69 and anti-CD16/anti-CD69 antibody pairs.B7-H6M4-OKT3 significantly upregulated CD69 on T cells (Figure 6B), while B7-H6M4-LC21 potently induced CD69 expression on NK cells (Figure 6C).