FCGR3B and infection: Thus, to understand whether prior infection shapes the functional potential of the mRNA vaccine-induced SARS-CoV-2 specific humoral immune response, we probed the ability of vaccine-induced antibodies to interact with the 4 low-affinity Fc-receptors in humans (FcγR2a, FcγR2b, FcγR3a, and FcγR3b) which largely direct innate immune effector functions (48, 49).