ARHGEF1 and neoplasm: Moreover, the function of ARHGEF1 was not restricted to tumour-specific T cell responses, since OVA antigen-specific CD8+ T cells responding to infection with Listeria monocytogenes expressing OVA exhibited a less terminally differentiated phenotype with increased levels of the memory marker CD127 in Arhgef1-cKO compared with cWT mice26 (Extended Data Fig. 5a–c).