Fig. 5. Coinjection of Lpp and live S. aureus worsens the skin damage and increases the bacterial burden in local skin.

The skin lesion size (mm²) (A), and frequency of skin abscess formation (B) in NMRI mice (n = 15/group) up to 3 days after subcutaneous (s.c.) skin coinjection with 20 μl of Staphylococcus aureus (S. aureus) SA113Δlgt mutant strain (2.4 × 10⁶ colony-forming units [CFU]/site) with either phosphate-buffered saline (PBS) or purified S. aureus lipoprotein, denoted as Lpl1(+sp) (5 µg/site). Bacterial counts (n = 15/group) (C) and the levels of D macrophage inflammatory protein-2 (MIP-2), E keratinocyte chemoattractant (KC), F monocyte chemoattractant protein 1 (MCP-1), and G myeloperoxidase (MPO) (n = 4–5/group) in the supernatant of skin biopsy homogenates of the mice 3 days after s.c. skin infection of SA113Δlgt mutant strain (2.4 × 10⁶ CFU/site) with either PBS or Lpl1(+sp) (5 µg/site). Data from three independent experiments with similar results were pooled (A–C). Samples from one representative experiment were used (D–G). The skin lesion size (mm²) development in NMRI mice (n = 5/group) up to 3 days (H) and bacterial counts (I), the levels of MIP-2 (J), KC (K), MCP-1 (L), and MPO (M) in the supernatant of skin biopsy homogenates of the mice 3 days after s.c. skin infection of SA113Δlgt mutant strain (2.4 × 10⁶ CFU/site) with either PBS or Lpl1(−sp) (5 µg/site). Statistical evaluations were performed using the Fisher’s exact test (B), Mann–Whitney U test, with data expressed as the mean ± standard error of the mean (A, H), or presented as scatterplot with line indicating median value (C–G, I–M). *P < 0.05; **P < 0.01; ns = not significant.