Isocitrate dehydrogenase 1/2 (IDH1/2) mutations have been detected in
gliomas, cartilaginous
tumors, and
leukemias. IDH1/2 mutations are early and frequent genetic alterations, are specific to a single
codon in the conserved and functionally important
Arginine 132 (R132) in IDH1 and
Arginine 172 (R172) in IDH2. We previously established several
monoclonal antibodies (mAbs), which are specific for IDH1 mutations: clones IMab-1 or HMab-1 against IDH1-R132H or clone SMab-1 against IDH1-R132S. However, specific mAbs against IDH2 mutations have not been reported. To establish IDH2-mutation-specific mAbs, we immunized mice or rats with each mutation-containing IDH2
peptides including IDH2-R172K and IDH2-R172M. After cell fusion, IDH2 mutation-specific mAbs were screened in
Enzyme-Linked
Immunosorbent Assay (ELISA). Established mAbs KMab-1 and MMab-1 reacted with the IDH2-R172K and IDH2-R172M
peptides, respectively, but not with IDH2-wild type (WT) in ELISA. Western-blot analysis also showed that KMab-1 and MMab-1 reacted with the IDH2-R172K and IDH2-R172M
recombinant proteins, respectively, not with IDH2-WT or other IDH2 mutants, indicating that KMab-1 and MMab-1 are IDH2-mutation-specific. Furthermore, MMab-1 specifically stained the IDH2-R172M-expressing cells in immunocytochemistry, but did not
stain IDH2-WT and other IDH2-mutation-containing cells. In immunohistochemical analysis, MMab-1 specifically stained IDH2-R172M-expressing
glioma. This is the first report to establish anti-IDH2-mutation-specific mAbs, which could be useful in diagnosis of mutation-bearing
tumors.