Fig 2.

TNF-α production and shedding of TNFR1 in response to protein A. RAW 264.7 cells were stimulated for the times indicated with wild-type S. aureus or a protein A-deficient mutant (spa mutant) (A and B), L. lactis expressing protein A (L. lactis SpA) or L. lactis containing a control vector (L. lactis CV) (C and D), E. coli (E), Pseudomonas aeruginosa (PAO-1) (F), or medium alone (unstimulated [U]), and the induction of TNF-α (A and C) and sTNFR1 (B, D, E, and F) was determined by ELISA. Data are means and standard deviations of cumulative data from three independent experiments (n, 3 for each experiment). Asterisks indicate significant differences (*, P < 0.05; **, P < 0.01) by Student's t test.