Figure 3. The divergent activation pathways of adaptive-like and innate-like γδ T cells.

The activation mechanisms of adaptive-like γδ T cells, so far, centre of Vδ1 mediated recognition of MHC-like molecules employing a heavy Vδ-dominance for cognate antigen ligation. Innate-like γδ T cells recognise bacterial lipid antigens (HMBPP & IPP) in a butyrophilin dependent manner and display a restricted Vγ gene pairing. Although the molecular basis remains unknown Vγ9⁺ and Vγ4⁺ TCR confer reactivity to BTN3A1 and BTNL3, respectively, thus implicating the γ-chain at the interface.