Figure 5.

TCCD analysis of a resting T cell. (a) All the components of the triggering apparatus of a T cell, i.e. MHC-peptide (HLA-DR), CD4 and CD45, give the same low value of association quotient (Q), a measure of the fraction of associated molecules, as the positive control monomeric protein, CD2. The dimer control, CD3, gives much higher levels of coincidence (each T-cell receptor contains two CD3 (epsilon) signalling subunits). The data are from James et al. [46]. (b) Cartoon of some of the likely stoichiometries of the triggering apparatus of the T cell, based on the TCCD experiments.