As a consequence, out of the three early HIV proteins, the model predicts that only an optimal epitope deriving from the Nef protein will be presented significantly early, around 12 hours post-infection, whilst the optimal epitopes from Rev and Tat do not appear on the cell surface in substantial amounts until after the optimal epitopes from the later proteins, Gag, Pol, Env, Vif, Vpr and Vpu, which appear at around 15–16 hours post infection (Fig. 4B). Here, TAT is linked to infection.