Fig. 1.

Adjuvant-induced ATP release in mouse muscles and the effect of apyrase. (A–D) Representative images taken 3 min after intramuscular injection of adjuvants (right hind limb; asterisk) or PBS (left hind limb) in BALB/c mice together with the mixture luciferase-luciferin that reports on ATP changes. (E–H) Corresponding quantitative analyses of chemiluminescence emission over time (number of photons per second in the region of interest). (A and E) MF59 (40% vol/vol), (B and F) CaPi (50 μg), (C and G) IFA (40% vol/vol), (D and H) alum (100 μg), and (I and J) ATP release from ex vivo mouse muscles injected with MF59. Mouse tibialis anterior (I) and quadriceps (J) muscles were exposed and injected with MF59 (40% vol/vol), continuous lines; the dotted line refers to the injection of the same volume of PBS. Muscles were rapidly removed and suspended in oxygenated buffer at 37 °C. ATP released into buffer was quantified at the given times, using the luciferin-luciferase assay and a known ATP standard. (K) Representative image taken 3 min after intramuscular injection of MF59 + apyrase (10 U; asterisk) or MF59 alone (contralateral muscle). (L) Corresponding quantitative analysis over time. Data show mean values + SD from at least four independent experiments. Unpaired, two-tailed Student’s t test (T): *P < 0.05, **P < 0.01, ***P < 0.001.