Fig. 4.

Activated CD8⁺ T cells can exchange antigen specificity in vitro by TCR transfer. FACS-purified WT OT-I, Prf^−/− OT-I and LCMV P14 CD8⁺ TCR transgenic T lymphocytes were cultured with cognate peptide-pulsed primary dendritic cells for 5 or 3 days and then mixed (Prf^−/− OT-I and LCMV P14) and cultured for another 2 days (Fig. S2). (A) CTL activity of unsorted splenocytes against SIINFEKL-pulsed targets. (B) CTL activity of FACS-sorted cells against SIINFEKL-pulsed targets. (C) CTL activity of FACS-sorted cells against KAVYNFATM (gp33 peptide)-pulsed targets. (D) The dual specificity of sorted CD8⁺ T cells was established by using K^b-SIINFEKL or K^b-KAVYNFATM tetramers to block killing in a ⁵¹chromium release assay at a 100:1 effector/target cell ratio.