Figure 3. Mammalian input activation of the AND-gated antibody.

The gated antibody allowed ‘dual-input’-only imaging of mammalian brain tissue. After stimulation by the representative circulating pathogenic marker LPS, mice brains were generated containing cells expressing varying combinations of input states (no input, antigen-input only, phosphatase (SEAP, shown by a purple triangle in cartoons) input only and dual input). After overnight incubation, mice were killed and the brains sliced into 10 μm thick sections. Only dual input gave rise to output (fluorescent cells are observed, bottom right) from the gated AND-Ab. In this way, a circulating pathogenic in vivo signal indirectly created a key input for the activation of the gated antibody relayed via endogenous cytokine. Nuclei staining by DAPI (blue). Scale bar, 50 μm. DAPI, 4′,6-diamidino-2-phenylindole.