Fig. 3.

CD4⁺ and CD8⁺ T cells are required simultaneously for the harmful effect induced by FCA-OMP-2 immunization. B6 (a), RAG-1^−/− [31] (b); CD4^−/−/CD8^−/− [33] (c); CD8^−/−[30] (D); and CD4^−/− [29] (e) mice (eight to 16 individuals per group) were immunized with FCA-OMP-2 or FCA as described in legend to Fig. 1. Fourteen days after the last immunization mice were infected with C. pneumoniae. Mice were sacrificed 14 days after challenge and individual IFU determined in lung homogenates. The mean log₁₀ IFU per lung ± s.e.m. are depicted. Cumulative data from two independent experiments are shown. Differences versus FCA-treated and infected mice are significant (P < 0·05, Student's t-test).