To further confirm the results of the ICS, the other sixty mice from the group vaccinated with pVAX1-Ub-M and thirty mice from the groups vaccinated with pVAX1 and PBS were tested by the IFN-γ ELISPOT assay at three different time points (as detailed in section 2.13). Data are expressed as the number of IFN-γ-secreting cells per two hundred thousand splenocytes. Peptide-specific IFN-γ ELISPOT responses were considered to be positive if the response (minus media background) was ≥ 3fold above the media response and ≥ 50 spot-forming cells (SFC)/2 × 10 5 splenocytes were registered.