a, Flow-cytometry exosome quantification from nt shRNA control and ADAM10 KD A549 cells; n = 3. b, Cell death, measured by LDH release, of A549 cells treated with α-toxin only, pretreated with HKSA or CpG DNA and α-toxin (‘induced’), or pre-exposed to HKSA or CpG DNA followed by PBS wash and then α-toxin treatment (‘induced; washed’); n = 5. c, Representative flow-cytometry histograms of CCR5 on CD81-positive, CD63-positive and CD9-positive exosomes isolated from mouse BMDMs. d, Exogenous exosome-transfer protocol. In step 1, donor mice are pre-exposed to HKSA i.v. to induce exosome production. In step 2, exosomes from donor mice are injected intraperitoneally (i.p.) on day −1, day 0 and day +1 following lethal i.v. injection of S. aureus. e, Survival of wild-type mice infected i.v. with a lethal dose of 5 × 107 CFU of S. aureus (USA300) that were mock-treated (n = 10) or injected i.p. with exosomes from Atg16l1HM mice (n = 8). f, Endogenous exosome-protection protocol. Mice are i.v. injected with HKSA to induce exosome production. Four hours later, mice are infected with a lethal dose of S. aureus (2.5–5 × 107). g, h, Western blot analysis of α-toxin oligomerization in total BAL or in exosome fraction in BAL of mice pre-exposed to HKSA or PBS intranasally (i.n.), representative of four independent experiments. i, j, Quantification of α-toxin monomer (i) and heptamer (j) in BAL and exosome fraction following pre-exposure; n = 4. k, Ratio of α-toxin heptamer in exosome fraction to total α-toxin signal in BAL; n = 4. Measurements were taken from distinct samples and graphs show means ± s.e.m. a, i–k, Two-tailed, unpaired t-test with Welch’s correction. b, One-way ANOVA with Dunnet’s post-test compared with α-toxin only or ‘induced’ controls. e, log-rank Mantel–Cox test. Source Data