The early peritoneal M-MDSC response is specific of mesotheliomagenic CNT. Proportion of (a) monocytic CD11b/cint and His48hi Myeloid Derived Suppressor Cells (M-MDSC) and (b) inflammatory CD11b/cint and His48int neutrophils in the peritoneal lavages performed on saline-, CNT-7- (2 mg), crocidolite asbestos- (Asb, 2 mg), DQ12 silica- (SiO2, 2 mg) or LPS- (E. coli, 5 μg) treated Wistar rats 1 day after ip injection. SiO2 and LPS are not mesotheliomagenic. c Proportion of peritoneal M-MDSC after ip injection of 2 mg CNT-7, short CNT-7 or asbestos at day 1. Each bar represents mean ± SEM of 4–5 observations. The results were statistically analyzed using the Dunnett’s Multiple Comparison test. * = p < 0.05, ** = p < 0.01, *** = p < 0.001 indicate a statistically significant difference with saline-treated rats (Ctl). d Proportion of peritoneal M-MDSC in the peritoneal cavity of rats after carcinogenic CNT-7 or non-carcinogenic CNT-M or CNT-T treatment (2 mg) at days 7, 15 and 30. The results were statistically analyzed using the Dunnett’s Multiple Comparison test. * = p < 0.05, ** = p < 0.01, *** = p < 0.001 indicate a statistically significant difference between saline-treated (day 0) and CNT-7-treated animals. ## = p < 0.01 indicates a statistically significant difference between saline-treated (day 0) and CNT-T-treated animals. $$ = p < 0.01 indicates a statistically significant difference between saline-treated (day 0) and CNT-M-treated animals