title: Novel monoclonal antibodies GMab-r1 and LMab-1 specifically recognize IDH1-R132G and IDH1-R132L mutations.
abstract: Isocitrate dehydrogenase 1 (IDH1) catalyzes the oxidative carboxylation of isocitrate to α-ketoglutarate in cytosol. IDH1 mutations, which are specific to a single codon in the conserved and functionally important Arginine 132 (R132), result in the ability of the enzyme to catalyze the reduced NADP-dependent reduction of α-ketoglutarate to onco-metabolite R(-)-2-hydroxyglutarate (2-HG). IDH1 mutations, which are early and frequent genetic alterations that occur in gliomas, cartilaginous tumors, and leukemias. We previously established two monoclonal antibodies (MAbs) that are specific for IDH1 mutations: clone HMab-1 against IDH1-R132H and clone SMab-1 against IDH1-R132S. However, specific MAbs against IDH1-R132G or IDH1-R132L have not been reported. To establish IDH1-R132G-specific or IDH1-R132L-specific MAbs, we immunized rats with each mutation-containing IDH1 peptides, and IDH1-R132G-specific or IDH1-R132L-specific MAbs were screened in ELISA. Established MAb GMab-r1 reacted with the IDH1-R132G peptide, but not with IDH1-wild type (WT) in ELISA. In contrast, LMab-1 reacted with the IDH1-R132L peptide, but not with IDH1-WT. Western blot analysis also showed that GMab-r1 and LMab-1 reacted with the IDH1-R132G and IDH1-R132L recombinant proteins, respectively, but not with IDH1-WT or other IDH1 mutants, indicating that GMab-r1 and LMab-1 are IDH1-mutation-specific. Furthermore, GMab-r1 and LMab-1 specifically stained the IDH1-R132G- and IDH1-R132L-expressing cells in immunocytochemistry, respectively. This is the first report to establish anti-IDH1-R132G-specific or IDH1-R132L-specific MAbs, which could be useful in the diagnosis of mutation-bearing tumors.
authors.affiliation: Regional Innovation Strategy Support Program, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.
authors.forename: Mika Kato
authors.initials: MK
authors.lastname: Kaneko
authors.forename: Yuta
authors.initials: Y
authors.lastname: Tsujimoto
authors.forename: Yasukazu
authors.initials: Y
authors.lastname: Hozumi
authors.forename: Kaoru
authors.initials: K
authors.lastname: Goto
authors.forename: Yukinari
authors.initials: Y
authors.lastname: Kato
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000918:Antibody Specificity / Q000276:immunology; D016466:CHO Cells; D002460:Cell Line; D003412:Cricetulus; D007521:Isocitrate Dehydrogenase / Q000235:genetics* / Q000276:immunology*; D009154:Mutation / Q000235:genetics / Q000276:immunology; D051381:Rats; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D011994:Recombinant Proteins; D007521:Isocitrate Dehydrogenase; C543588:IDH1 protein, human