Fig 8. Commensal presence promotes IL-1ß release during infection.

A. Differential presence of IL-1ß transcripts in the conjunctival tissues of GF and SPF SW mice. Quantitative RT-PCR for IL-1ß and IL-1α transcripts were carried out using conjunctival tissues from GF and SPF mice. GF conjunctival tissues have significantly lower levels of IL-1ß transcripts when compared to SPF-derived tissues. Data were pooled from two independent experiments and plotted as median values with range. The circles represent individual mice. p-values by Student’s t-test. Bonferroni correction for multiple comparisons p = 0.025.B. IL-1β protein levels in the corneal tissues of infected GF and SPF mice with P. aeruginosa 6294. Groups of GF (n = 5) and SPF-SW (n = 5) mice were infected with 1×10⁷ CFU P. aeruginosa 6294 onto eyes. Infected GF mice mount significantly less IL-1ß when compared to SPF mice. Data were pooled from two experiments. p-values by Student’s t-test. C. IL-1ß levels measured by ELISA in the corneal tissues of either mice treated topically with gentamycin or control mice infected with P. aeruginosa PA01. Topical gentamycin treatment significantly reduced the levels of IL-1ß released during infection. Data were median values with range. p-values by Student’s t-test. D. Neutralization of IL-1ß increased corneal bacterial burden in the resistant SPF SW mice (n = 6) when compared to the control mice (n = 6). p-values by Student’s t-test. Data are pooled from two performed experiments.