Figure 2

Presence of intact IL-1Ra in serum after intra-colonic administration of IL-1Ra-producing B. subtilis. Left: Human IL-1Ra in colon washings and in serum of rats receiving a single intra-colonic instillation of 3 × 10⁸ live cells of B. subtilis pSM214 (β-lactamase control) or pSM539 (producing IL-1Ra). The presence of IL-1Ra was assessed by Western blotting on samples of colon washings (upper panel) and serum (lower panel) taken at different time points. Samples at time 0 were from animals receiving pSM539 immediately before sampling. Results at time 0 from rats treated with pSM214 and untreated rats were also negative (data not shown). An aliquot of standard human recombinant IL-1Ra (7–14 ng) was included as reference in each gel. Right: Presence of human IL-1Ra in serum of rabbits receiving an intra-colonic instillation of 2 × 10⁹ live cells of B. subtilis pSM539 (producing IL-1Ra; ●) or pSM214 (β-lactamase control;○). IL-1Ra concentration was assessed by ELISA. Data are the mean ± SEM of values from 3 rabbits/group in one representative experiment. Overlapping results were obtained with sera of rats after intra-colonic administration of recombinant B. subtilis, and by BIAcore analysis of human IL-1Ra presence in rat and rabbit serum samples (data not shown). Statistical significance: pSM539 vs. pSM214 p < 0.01 at every time.