ACE2 and infection: In a study using ACE2 and FcRII-bearing HL-CZ human promonocyte cells, anti-Spike antibodies were associated both with efficient neutralization or ADE in a concentration-dependent manner; sera with diluted anti-Spike-antibodies tended to enhance infection, whereas that with concentrated anti-Spike-antibodies promoted protection through neutralization (Wang et al., 2014).