Additionally, within seropositive and/or positive infection history organoid SARS-CoV-2-spheromer+ CD8+ T cells, SARS-CoV-2 infection stimulated expression of the AIM markers 4–1BB, CD25, OX40 and CD40L versus mock controls, which did not occur in the seronegative donor organoids (Fig. 6d–e, Extended Data Fig. 10a). Here, TNFRSF4 is linked to infection.