The ability of IVTT products to stimulate an antigen-specific T cell response in vitro was evaluated in the P. yoelii CSP model. Splenocytes from mice (n = 5/group) immunized with VR2516 PyCSP plasmid DNA or VR1020 control plasmid were stimulated in vitro with unpurified rPyCSP IVTT; rPyCSP IVTT associated to Polybeads or ProteinG beads; rPyCSP IVTT purified using NI-NTA resin, MagneHis Ni-particles, or anti-HIS; or synthetic peptides representing defined T cell epitopes from PyCSP. Antigen-specific cytokine production was assayed using IFN-c ELISpot or CBA assays.