HSF4 and neoplasm: These results demonstrate that IFP constructs that exceed the physiological extracellular length (CTM + 12EC, CTM + 39EC, and CTM + 41EC) induce CAR-independent T cell activation (Fig. 2g), proliferation (Fig. 2b) and tumour lysis (Fig. 2a) upon coculture with PD-L1+ Nalm-6 tumour cells in vitro.