Figure 3.

Enumeration of peptide-specific CD8⁺ T cells in the BAL during acute and recrudescent infection by staining with tetrameric major histocompatibility complex class I/peptide complexes. The results show one representative experiment from the data illustrated in Table 1. No significant staining (<0.2%) was observed either with the MHV-68 tetramers by using lymphocytes from naive mice, or with H-2D^b-ASNENMETM (influenza virus epitope) or H-2K^b-FAPGNYPAL (Sendai virus epitope) tetramers (19) using the MHV-68-immune lymphocytes. The identity of the tetramer-positive CD8⁺ cells as T cells was further confirmed by staining with CD3, T cell receptor beta chain, and Thy-1 (data not shown).