“…Participants Sera were obtained from individuals with newonset type 1 diabetes, and from islet autoantibody-negative participants in the TeenDiab cohort of prospectively followed first-degree relatives of individuals with type 1 diabetes [5,6] Tetraspanin 7 fragment and mutant proteins The truncated C1 (amino acid [AA] 1-16), C1-TM1 (AA 1-40), C1-TM1-E1-TM2 (AA 1-75), C1-TM1-E1 (AA 1-56), TM1-E1-TM2-C2 (AA 17-86), E1-TM1-C2 (AA 41-86), C2 (AA 76-86), TM2-C2-TM3-E2 (AA 57-213), C2-TM3-E2 (AA 76-213), TM3-E2-TM4-C3 (AA 87-249), E2-TM4-C3 (AA 113-249), TM4-C3 (AA 214-249) and C3 (AA 235-249) tetraspanin 7 fragments NH 2 -terminally fused to NanoLuc were constructed by PCR amplification from full-length tetraspanin 7 [7] and cloning into pCMV6-AC-IRES-GFP-Puro (Origene, Rockville, MD, USA) containing NanoLuc. Mutations at the C3 residues of the NanoLuc-TM3-E2-TM4-C3 construct were introduced using QuickChange Site-directed Mutagenesis (Agilent, Santa Clara, CA, USA).…”