Fig. 2: Ingress into M. marinum granulomas protects M. abscessus from innate immunity.

A Schematic illustrating embryo superinfection experimental set up. Abbreviation: Days post secondary infection (dpsi). B Still images extracted 900 minutes apart from Supplementary Movie 1. Site of M. abscessus (purple) injection is into Tg(kdrl:egfp)-positive vasculature (green) below primary M. marinum granuloma (yellow). Scale bars indicate 100 μm. C Quantification of secondary M. abscessus burden in 3 dpsi embryos infected with primary M. marinum. Naive n = 32, primary M. marinum n = 40, two-sided T test. D Quantification of secondary M. abscessus burden in 3 dpsi embryos infected with primary M. marinum grouped by quartile of M. abscessus found within M. marinum granulomas. Q1 and Q4 n = 10, Q2 and Q3 n = 11, one-way ANOVA. E Correlation of the percentage of secondary M. abscessus found within M. marinum granulomas (Percentage colonization) with total body secondary M. abscessus burden (M. abscessus fluorescent pixel count) in 3 dpsi embryos, n = 42, R squared value calculated by linear regression. F Quantification of secondary M. abscessus burden in 3 dpsi embryos infected with primary M. marinum, M. abscessus was delivered by co-injection with clodronate microsomes. PBS n = 21, clodronate n = 25, one-way ANOVA. G Quantification of fold change in M. abscessus burden during treatment with 10 μM clarithromycin from 2 dpsi to 4 dpsi. Naive (DMSO) n = 14, Naive (Clarithromycin) n = 18, Primary M. marinum (DMSO) n = 21, Primary M. marinum (Clarithromycin) n = 19, one-way ANOVA. Data are presented as mean values +/- SD.