In vivo stimulation of PyCSP antigen-specific T cell response using IVTT products We next evaluated the capacity of unpurified and purified IVTT products to boost PyCSP primed immune responses in vivo. Mice (n = 5/group) were primed with VR2516 PyCSP plasmid DNA and then boosted in vivo with unpurified rPyCSP IVTT, PyCSP IVTT associated to Polybeads or ProteinG beads, or PyCSP IVTT purified using NI-NTA resin or MagneHis Niparticles, all adjuvanted with Alum. Splenocytes were stimulated in vitro with A20 target cells transfected with VR2516 PyCSP DNA or A20 cells pulsed with PyCSP synthetic peptides. Antigen-specific cytokine production was assayed using IFN-c ELISpot or CBA assays.