Fig. 7.

Proposed mechanisms of ADCC bystander killing in AQP4-IgG seropositive NMOSD. Diagram shows AQP4-IgG binding to AQP4 on astrocytes, with binding and activation of NK cells through Fcγ receptors. Activated NK cells can induce bystander cell damage via three mechanisms, including: (i) targeted lytic protein secretion onto immediately adjacent bystander cells following activation; (ii) sequential attack of target cells followed by release and binding/attack of a nearby bystander cell; and (iii) release of soluble granule contents following activation that then diffuse through the extracellular medium and are deposited on nearby cells