FIG. 6.

Epitope-positive CD8 T cells are activated. (A) Splenocytes from uninfected and infected mice were surface stained with CD44 and CD62L at 6, 10, 17, and 42 dpi. Representative stains are shown for each time point for the total CD8 T-cell population and for one of the epitope-positive populations (H-2K^b/KSLTYYKL). (B) In vitro stimulation of splenocytes from MHV-68-infected mice with no peptide (−), phorbol ester (phorbol myristate acetate [PMA]) and ionomycin, selected MHV-68 epitopes (the early KSLTYYKL/H-2K^b epitope, the late TSINFVKI/H-2K^b epitope, the early SAIENYETF/H-2D^b epitope, and the late AGPHNDMEI/H-2D^b epitope), or the known H-2K^b binding peptide SIINFEKL (SII) or known H-2D^b binding peptide ASNENMDAM (ASN) demonstrates that CD8 T cells produce IFN-γ in an epitope-specific fashion. The data shown are representative of independent experiments. APC, allophycocyanin; FITC, fluorescein isothiocyanate.