Figure 5. A Sialidase-based Acne Vaccine Suppresses Induction of the Pro-inflammatory Cytokine MIP-2 by P. acnes.

(A) A tissue chamber (a) (internal and external diameters, 1.5 and 3 mm, respectively, length, 1 cm; internal volume, 80 µl) was implanted subcutaneously in the abdomen of sialidase- or GFP-immunized mice. The tissue chamber consisted of closed ploytetrafluoroethylene Teflon cylinders with 12 regularly spaced 0.1 mm holes. Bar: 1 cm. H&E staining of the cross-section of an implanted tissue chamber showed that the chamber was completely encapsulated by fibrotic tissue 7-days after implantation (b). Bar: 1.0 mm. P. acnes (10⁷ CFU, 20 µl) was injected and trapped in this encapsulated tissue chamber. (B) Tissue chamber fluid containing MIP-2 was drawn by pecutaneous aspiration before (open bar) and three days after (solid bar) P. acnes injection. Measurement of MIP-2 was carried out by sandwich ELISA that used the Quantikine M mouse MIP-2 set (R&D System, Minneapolis, MN). Vaccination with sialidase markedly suppressed the P. acnes-induced increase in MIP-2. Error bars represented mean±SE of five separate experiments (*P<0.005 by Student's t-test).