Fig. 5

Influenza mediates C3 release from platelets through TLR7. a C3 in plasma from healthy donors (n = 14) and influenza-infected patients (n = 18). The graphs represent the average ± SD; significance was assessed by Mann–Whitney U test, *p < 0.0001. b C3 release from human platelets that express TLR7 (assessed by qPCR) had been isolated from healthy donors and mixed with influenza strain WSN/33 at a proportion of 1 pfu to 100 platelets (n = 4, 3F, 1M); p < 0.0001, F = 27.49, df = 3. c C3 release from human platelets that do not express TLR7 (assessed by qPCR) treated as in (b). Graph is representative of n = 3 different blood draws; p = 0.2813, F = 1.833, df = 3. d C3 release from human platelets from the same donors as in (b) treated with the TLR7 agonist loxoribine 1 mM in the presence or absence of TLR7 inhibitor IRS661; p = 0.0086, F = 7.989, df = 3. b–d Data in graphs are represented as average ± SD; significance was assessed using ANOVA followed by Bonferroni multiple comparison test and star symbol (*) indicates p < 0.05. Source data for (a–d) are provided as a Source Data file. e Confocal images of permeabilized isolated platelets from influenza-infected patient stained for flu-FITC; TLR7-APC; lysosomal marker CD63-BV421. f Confocal images of isolated healthy human platelets incubated with WSN/33 for 30 min (1 pfu to 10 platelets) and stained as in (e). e, f Representative images of platelets from n = 4 (2M, 2F) different donors are shown