These results showed that precise molecular interaction with high specificity is involved in these receptor interactions. Similar results were observed in the γδ TCR-CD23 binding, where head-on interactions were observed between the two receptors. The binding site of the two receptors is shown in Figure , and the docked structure is shown in Figure . It is relevant to note that in the resting state, CD23 exists in a monomeric form, and in the presence of an external signal, it forms a dimer and results in signal transduction. We assume that the CAR T cell binds only to the monomeric form. The binding site is exposed in monomeric form; in the dimeric form, it gets hidden.