FIG. 3.

(A) Lysis of C. pneumoniae-infected target cells by CTL line 8482 in a 10-h ⁵¹Cr release assay. The CTL line was stimulated with splenocytes of a mouse immunized with Omp2-derived peptide 8482. BALB/3T3 target cells were infected in vitro with C. pneumoniae and labeled with ⁵¹Cr. Uninfected control cells were treated similarly without addition of C. pneumoniae. An E/T cell ratio of 10 was used. (B) The TNF-α production of CTL line 8482 in the presence of infected BALB/3T3 cells was significantly higher than the background level or the response to uninfected target cells. We stimulated 3 × 10⁵ CTLs with the same number of infected target cells (E/T cell ratio of 1) on 24-well plate for 48 h, after which the supernatants were collected and analyzed by ELISA. BD, below detection limit.