FIG. 3.

Proliferative response and IFN-γ production induced by recombinant CyaA are greatly increased by the insertion of two or three copies of the LCMV epitope. BALB/c mice were injected i.p. with 10 μg of recombinant CyaA in PBS carrying, as indicated, no copies (CyaA-wt), one copy, two copies, three copies, or four copies of the LCMV epitope. Seven days later, spleen cells were stimulated in vitro with the LCMV peptide. Four days later, stimulated splenocytes were monitored for the proliferative response (A), and the supernatants were tested for cytokine content (B). Results are expressed as mean [³H]thymidine incorporation or as the mean concentration of cytokines released in the supernatant from triplicate wells and are representative of five experiments. Standard deviations were always <10% of the maximum response.