Microbial and autoantibody immunogenic repertoires in TIF1? autoantibody positive dermatomyositis

Spyridon Megremis; Thomas Walker; Xiaotong He; James O'Sullivan; William E.R. Ollier; Hector Chinoy; Neil Pendleton; Antony Payton; Lynne Hampson; Ian Hampson; Janine Lamb

We retrieved 13,385,371 distinct expressed AA epitopes that represent the epitope signatures present within the DM and HC Ig pools (Fig. S1A ). Associated NGS read frequencies reflected the epitope enrichment process achieved during biopanning, and Fig. S1B & C confirms that the 10-σ-99 NGS filter optimally controlled biopanning-induced sequencing noise to successfully provide 15,522 DMassociated and 4,817 HC-associated unique epitope sequences. Preferential enrichment for epitopes of length 11 and 12 AAs (Fig. S1D ) confirmed genuine biopanning capture and is concordant with published peptide epitope ranges of 4 to 12 AAs (Buus et al., 2012; Hopp and Woods, 1981) . Minimum epitope lengths of 9AA applied with the 10-σ-99 NGS filter (above) proved optimal for annotation ( Fig. S1E ) using the unique sequence epitope sets of 15,522 for DM and 4,817 for HC individuals (Fig. S1F ). Ig repertoire sequence overlap determined that only 0.65% of DM epitope set were present in healthy controls (fold-change (FC) values of >=5x to 546x abundance vs HC individuals) while 6.44% of healthy epitope set was retained in the DM group (FC values of >=5.3x to 1240x vs DM) (Fig. S1F) .