MONOCLONAL ANTIBODIES IN IMMUNODIAGNOSIS AND IMMUNOTHERAPY
Volume 32, Number 6, 2013ª Mary Ann Liebert, Inc.
DOI: 10.1089/mab.2013.0050

Original Articles

Multi-Specific Monoclonal Antibody MsMab-2 Recognizes
IDH1-R132L and IDH2-R172M Mutations
Satoshi Ogasawara,* Mika Kato Kaneko,* Yuta Tsujimoto,* Xing Liu, and Yukinari Kato

Mutations of isocitrate dehydrogenase 1/2 (IDH1/2) produce oncometabolite R(-)-2-hydroxyglutarate in several
tumors. Arginine 132 (R132) of IDH1 and arginine 172 (R172) of IDH2 are functionally important residues.
Although MsMab-1 monoclonal antibody (MAb), which is multi-specific for mutated IDH1/2, has been established, MsMab-1 does not react with all IDH1/2 mutations. Herein, we immunized rats with IDH1-R132L
peptide, and screened IDH1-R132L-reactive/IDH1-wild-type non-reactive MAbs in enzyme-linked immunosorbent assay. Unexpectedly, the newly established MsMab-2 MAb recognized not only IDH1-R132L but also
IDH2-R172M in Western blot analyses, neither of which was detected by MsMab-1. Taken together, the combination of MsMab-1 and MsMab-2 could be useful in diagnosis of mutated IDH1/2-bearing tumors.

IntroductionIsocitrate dehydrogenase 1/2 (IDH1/2) catalyzes theoxidative carboxylation of isocitrate to a-ketoglutarate.(1)In contrast, somatic mutations of IDH1/2 were found toconvert a-ketoglutarate to oncometabolite R(-)-2-hydroxyglutarate (2-HG). Most changes by far are heterozygous. A
recent report describes two gliomas that lost the wild-type
IDH1 allele but retained the mutant IDH1 following tumor
progression from anaplastic astrocytoma to glioblastoma.(2)The intratumoral 2-HG level was 14-fold lower in the glioblastomas lacking wild-type IDH1 compared with glioblastomas of heterozygous IDH1 mutations, indicating that bothwild-type and mutant IDH1 alleles are necessary for 2-HG
production in glioma cells. It is noteworthy that the expression of mitochondrial IDH2 mutations led to robust 2-HG
production in a manner that is independent of wild-type
mitochondrial IDH function.(3) Another report demonstrated
that 2-HG can inhibit histone demethylation and that inhibition of histone demethylation can be sufficient to block the
differentiation of non-transformed cells.(4) Turcan and colleagues also showed that IDH1 mutation is sufficient to establish the glioma hypermethylator phenotype.(5) Taken
together, the blockade of 2-HG production by inhibiting thefunctional mutated IDH1/2 is thought to be an ideal molecular targeting therapy against gliomas and leukemias.(6,7)
The IDH1 mutations are remarkably specific to a single codon
in the conserved and functionally important arginine 132 residue(R132).(8) In contrast, the IDH2 mutations are specific to a single
codon in arginine 172 residue (R172). IDH2 mutations of leukemias were discovered subsequently in arginine 140 residue(R140), which is found more frequently than R172.(9) In gliomas,

IDH1 mutations were reported as IDH1-R132H (664/716,
92.7%), IDH1-R132C (29/716, 4.2%), IDH1-R132S (11/716,
1.5%), IDH1-R132G (10/716, 1.4%), and IDH1-R132L (2/716,
0.2%).(10) In contrast, IDH2 mutations were reported as IDH2R172K (20/31, 64.5%), IDH2-R172M (6/31, 19.3%), and IDH2R172W (5/31, 16.2%) in gliomas. To date, we have establishedseveral mono-specific monoclonal antibodies (MAbs) against
IDH1/2 mutations.(11–17) A recent report has described a multispecific anti-mutated IDH1/2 monoclonal antibody, MsMab-1,
which is useful for diagnosis of IDH1/2 mutation-bearing gliomas.(18,19) Herein, we report another multi-specific MAb, MsMab2, which can react with MsMab-1-negative IDH1/2 mutations.
Materials and Methods
Cell lines
Chinese hamster ovary (CHO)-K1 and Sp2/0-Ag14 wereobtained from the American Type Culture Collection (ATCC,
Manassas, VA) and was cultured at 37C in a humidified atmosphere of 5% CO2 and 95% air in RPMI 1640 medium,including 2 mM L-glutamine (Nacalai Tesque, Kyoto, Japan)
supplemented with 10% heat-inactivated fetal bovine serum(FBS, Life Technologies, Carlsbad, CA).
Hybridoma production
MsMab-2 was produced using rat medial iliac lymph node
methods.(18) The institutional animal committee approved
our study. Briefly, WKY/Izm rats ( Japan SLC Inc., Shizuoka,
Japan) were immunized by injecting 170 mg of synthetic peptides of CGGVKPIIIGLHAYGDQYRA (IDH1-R132L), conjugated with KLH together with Freund’s complete adjuvant

Department of Regional Innovation, Tohoku University Graduate School of Medicine, Aoba-ku, Sendai, Miyagi, Japan.
*These authors contributed equally to this work.

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(FCA, Sigma-Aldrich, St. Louis, MO) into the footpad. The
lymphocytes were fused with mouse myeloma Sp2/0-Ag14
cells using polyethylene glycol (PEG). The culture supernatants were screened using ELISA for binding to the IDH1R132L and IDH1-WT peptides, conjugated with BSA.
Enzyme-linked immunosorbent assay
Synthetic peptides or recombinant proteins were immobilized on Nunc Maxisorp 96-well immunoplates (Thermo
Fisher Scientific, Waltham, MA) at 1 mg/mL for 30 min. Synthetic peptides are as follows: GGVKPIIIGRHAYGDQYRA(IDH1-WT), GGVKPIIIGHHAYGDQYRA (IDH1-R132H),GGVKPIIIGCHAYGDQYRA (IDH1-R132C), GGVKPIIIGSHAYGDQYRA (IDH1-R132S), GGVKPIIIGGHAYGDQYRA(IDH1-R132G), GGVKPIIIGLHAYGDQYRA (IDH1-R132L),
and GGVKPIIIGVHAYGDQYRA (IDH1-R132V). After
blocking with SuperBlock T20 Blocking Buffer (Thermo Fisher
Scientific), the plates were incubated with culture supernatantor purified MAbs (1 mg/mL) with subsequent 1:1000 diluted
peroxidase-conjugated anti-rat IgG or anti-mouse IgG (Dako,
Glostrup, Denmark). The enzymatic reaction was conductedwith 1-Step Ultra TMB-ELISA (Thermo Fisher Scientific). The
optical density was measured at 655 nm using an iMark microplate reader (Bio-Rad Laboratories, Philadelphia, PA). These
reactions were performed with a volume of 50 mL at 37C.
Plasmid preparation
Human IDH1 cDNA (GenBank accession no. AF113917)
and human IDH2 cDNA (accession no. NM_002168) encoding
a full-length open-reading frame (ORF) were obtained using
PCR with a human lung cDNA library (Cosmobio Co., Tokyo,
Japan) and cDNA derived from the U373 glioblastoma
cell line as template, respectively. The primer set for IDH1
was: EcoRI-IDH1-F1, 5¢-cacgaattcATGTCCAAAAAAATCA
GTGG-3¢ and SalI-IDH1-R1, 5¢-gtggtcgacTTAAAGTTTGGCCTGAGCTA-3¢; and for IDH2: EcoRI-IDH2.F1, 5¢-ccgaattc
gggATGGCCGGCTACCTGCGGG-3¢
and
SalI-IDH2wterR1359, 5¢-gccgtcgacCTACTGCCTGCCCAGGGCTCT-3¢.
The amplified cDNA was subcloned into a pcDNA3.1/V5His-TOPO vector (Life Technologies). Substitution of the arginine 132 (R132) to appropriate amino acid codons in IDH1
or arginine 172 (R172) to appropriate amino acid codons in
IDH2 was done using the QuikChange Lightning site-directed mutagenesis kit (Agilent Technologies, Santa Clara,
CA). The full-length IDH1 was subcloned into an expression
vector, pMAL-c2 (New England Biolabs, Beverly, MA), via
EcoRI and SalI restriction sites. The full-length IDH2 and eachmutated ORF were amplified using the primer set EcoRIIDH2.F1 and IDH2woterR1356-XhoI, 5¢-taactcgagcgCTGCC
TGCCCAGGGCTCTG-3¢. These PCR products were digested
with EcoRI and XhoI restriction enzymes and were subcloned
into pcDNA3 vector (Life Technologies) together with thenucleotide sequence (ctcgagTGGCGTTGCCATGCCAGGTGCCGAAGATGATGTGGTGTAAtctaga), which encodes 12
amino acids, GVAMPGAEDDVV (PA tag).(13,16,18,19)
Protein expression using bacteria cells
and mammalian cells
Competent Escherichia coli TOP-10 cells (Life Technologies)
were transformed with the plasmid pMAL-IDH1-WT, pMAL-

OGASAWARA ET AL.
IDH1-R132H, pMAL-IDH1-R132C, pMAL-IDH1-R132S,
pMAL-IDH1-R132G, pMAL-IDH1-R132L, or pMAL-IDH1R132V. Then they were cultured overnight at 37C in LB
medium (Life Technologies) containing 100 mg/mL ampicillin(Sigma-Aldrich). Cell pellets were resuspended in phosphatebuffered saline (PBS) with 1% Triton X-100 with 50 mg/mL
aprotinin (Sigma-Aldrich). After sonication using Branson
Advanced Sonifier (Branson Ultrasonics, Danbury, CT), thecrude extracts were collected by centrifugation (9000 g, 30 min,4C). The supernatants were loaded onto amylose resin (NewEngland Biolabs). The loaded resins were washed extensively with column buffer (20 mM Tris-HCl [pH 7.4], 200 mM
NaCl, 1 mM EDTA). The fusion proteins were eluted by column buffer with 10 mM maltose. Then CHO cells were transfected with appropriate amounts of plasmids (pcDNA3.1/
IDH1-WT, pcDNA3.1/IDH1-R132H, pcDNA3.1/IDH1-R132C,
pcDNA3.1/IDH1-R132S, pcDNA3.1/IDH1-R132G, pcDNA3.1/
IDH1-R132L, pcDNA3.1/IDH1-R132V, pcDNA3/IDH2-R172K,
pcDNA3/IDH2-R172M, pcDNA3/IDH2-R172W, pcDNA3/
IDH2-R172G, pcDNA3/IDH2-R172S) using Lipofectamine LTX(Life Technologies) according to the manufacturer’s instructions.
The expression level of IDH1/2 was confirmed using Western
blot analysis.
Western blot analyses
Cultured cell pellets were lysed with PBS with 1% TritonX100 for 30 min on ice. The lysate supernatants were centrifuged for 15 min at 15,000 rpm to remove cellular debris. Cell
lysates were prepared for Western blot analyses by boiling in
SDS sample buffer (Nacalai Tesque). They were electrophoresed on 5–20% polyacrylamide gels (Wako Pure Chemical Industries). The separated proteins were transferred to a
PVDF membrane (EMD Millipore, Billerica, MA). After
blocking with 4% skim milk in PBS with 0.05% Tween-20 for
15 min, the membrane was incubated with 1 mg/mL of primary antibodies for 30 min. Then the membrane was incubated with peroxidase-conjugated secondary antibodies(1:1000 diluted; Dako) for 15 min and developed with ImmunoStar LD Chemiluminescence Reagent (Wako Pure
Chemical Industries) using Sayaca-Imager (DRC Co., Tokyo,
Japan).
Results and Discussion
Production of an IDH1-R132L-specificmonoclonal antibody
We previously established several mono-specific anti-mutated IDH1/2 MAbs: HMab-1 against IDH1-R132H, SMab-1
against IDH1-R132S, GMab-r1 against IDH1-R132G, KMab-1
against IDH2-R172K, MMab-1 against IDH2-R172M, andWMab-1 against IDH2-R172W.(11–17) Recently we reported amulti-specific MAb MsMab-1 that recognizes IDH1-R132H,
IDH1-R132S, IDH1-R132G, and IDH2-R172M, but not IDH1/
2 wild type of mammalian cells in Western blot analyses.(18)
Furthermore, MsMab-1 is very useful in immunohistochemistry against mutated IDH1/2-possessing gliomas. However,MAbs against other IDH1/2 mutations, including IDH1R132L, are still necessary to cover all IDH1/2 mutations in
immunohistochemistry. Here, we immunized rats with synthetic peptides of IDH1-R132L and screened IDH1-R132Lreactive/IDH1 wild-type non-reactive MAbs using ELISA.

MULTI-SPECIFIC MAb MsMab-2 AGAINST IDH1/2 MUTATIONS
After limiting dilution, clone MsMab-2 (rat IgG2a, kappa)
against IDH1-R132L was established.
Specificity of multi-specific MAbs against IDH1
peptides and proteins in ELISA
The specificity of MsMab-2 and MsMab-1 was investigatedby ELISA using synthetic IDH1 peptides (IDH1-WT, IDH1R132H, IDH1-R132C, IDH1-R132S, IDH1-R132G, IDH1R132L, IDH1-R132V) or purified IDH1 proteins expressed in
Escherichia coli. As depicted in Figure 1A, MsMab-2 strongly
reacted with IDH1-R132L peptide, moderately with IDH1R132S, IDH1-R132G, and IDH1-R132V peptides, and very
weakly with IDH1-R132H peptide. In contrast, MsMab-2
weakly recognized IDH1-R132S, IDH1-R132G, and IDH1R132L recombinant proteins. Compatible with previous
reports, MsMab-1 strongly recognized IDH1-R132H, IDH1R132S, and IDH1-R132G peptides and weakly with IDH1R132C and IDH1-R132L peptides (Fig. 1B). Recombinant
proteins of IDH1-R132S and IDH1-R132G were detected
strongly by MsMab-1, although the reaction against IDH1R132H was slightly better compared with wild-type IDH1.
When the concentration of coated IDH1-WT peptide or protein was increased or the concentration of MsMab-1 MAb was

FIG. 1. Reactivity of multi-specific antibodies against IDH1
peptides and proteins by ELISA. Synthetic peptides or purified proteins of IDH1 wild type (WT) and mutants (R132H,
R132C, R132S, R132G, R132L, R132V) expressed in E. coli
were immobilized, followed by MsMab-2 (A) and MsMab-1(B). Data are representative of mean – S.D. of triplicates.

379

increased in ELISA, the reactivity of MsMab-1 against IDH1WT was also augmented (data not shown), demonstratingthat the concentration of MsMab-1 MAb is very critical in
immunohistochemistry to detect only IDH1/2 mutations.
These results indicate that MsMab-2 is a multi-specific MAb
against several IDH1 mutations, although MsMab-2 wasproduced by immunizing IDH1-R132L peptide.
Specificity of anti-mutated IDH MAbs in Western
blot analyses
To further determine the specificity of MsMab-2 against
IDH1/2 mutations, IDH1/2-WTs and IDH1/2 mutants(IDH1-R132H, IDH1-R132C, IDH1-R132S, IDH1-R132G,
IDH1-R132L, IDH1-R132V, IDH2-R172K, IDH2-R172M,
IDH2-R172W, IDH2-R172G, IDH2-R172S) were transiently
expressed in CHO cells and were Western blotted using
MsMab-2 and other anti-IDH1/2 MAbs. As shown in Figure
2, MsMab-2 recognized not only IDH1-R132L protein but also
IDH2-R172M protein. Unexpectedly, the reactivity of MsMab2 against IDH2-R172M was much stronger than that against
IDH1-R132L. In contrast, MsMab-1 strongly reacted with
IDH1-R132S, IDH1-R132G, IDH2-R172G, and IDH2-R172S;
moderately with IDH1-R132H; and weakly with IDH2R172M, indicating that MsMab-2 epitope is totally different
from MsMab-1 epitope. Recombinant human IDH1 and endogenous hamster IDH1 proteins were detected by RcMab-1
MAb. In contrast, only IDH2-WT and IDH2-R172K wererecognized by KrMab-3. These results indicate that only one

FIG. 2. Western blot analyses by anti-IDH1/2 MAbs
against wild-type and mutated IDH1/2 proteins. Total celllysate from CHO cells expressing IDH1 (lane 1, IDH1-WT;
lane 2, IDH1-R132H; lane 3, IDH1-R132C; lane 4, IDH1R132S, lane 5, IDH1-R132G; lane 6, IDH1-R132L; lane 7,
IDH1-R132V) and IDH2 (lane 8, IDH2-WT; lane 9, IDH2R172K; lane 10, IDH2-R172M; lane 11, IDH2-R172W; lane 12,
IDH2-R172G; lane 13, IDH2-R172S) were electrophoresed
under reducing conditions using 5–20% gels and wereWestern blotted with MsMab-2, MsMab-1, RcMab-1, KrMab3, anti-V5 tag, and anti-PA tag. RcMab-1 detected two bands,
including recombinant human IDH1 (arrowhead) and endogenous hamster IDH1 (arrow).

380
mutation at codon R132 of IDH1 or R172 of IDH2 makes
conformational variation of IDH1/2 proteins.
In conclusion, the newly established MsMab-2 is a multispecific MAb that recognizes IDH1-R132L and IDH2-R172M
of mammalian cells. The combination of MsMab-2 andMsMab-1 covers more than 95% of IDH1 mutations, which
could be extremely useful for diagnosis and biological evaluation of IDH1/2 mutation-bearing tumors. Unfortunately,
we could not obtain an IDH1-R132L or IDH2-R172Mpossessing specimen in this study; therefore, we could notshow clearly the usefulness of MsMab-2 in immunohistochemistry. Nevertheless, MsMab-2 is believed to be useful inimmunohistochemistry because MsMab-2 is able to react
strongly with recombinant proteins expressed in mammaliancells (Fig. 2). The combination of multi-specific MAbs withpreviously established anti-mutated IDH2 mono-specific
MAbs (KMab-1 and WMab-1) covers almost all IDH2 mutations, and could increase the diagnostic rate of IDH1/2 mutation-bearing tumors.
Acknowledgments
We thank Takuro Nakamura and Noriko Saidoh for their
excellent technical assistance. This work was supported inpart by the Platform for Drug Discovery, Informatics, andStructural Life Science (Y.K., M.K.K., S.O.), by Regional Innovation Strategy Support Program (Y.K.), by KAKENHI(25462242): Grant-in-Aid for Scientific Research (C) (Y.K.)
from the Ministry of Education, Culture, Sports, Science andTechnology of Japan, by Office for Women Researchers of
Tohoku University (M.K.K.), and by Intelligent Cosmos
Academic Foundation (Y.K.).
Author Disclosure Statement
The authors have no financial interests to disclose.
References
1. Dang L, White DW, Gross S, Bennett BD, Bittinger MA,
Driggers EM, Fantin VR, Jang HG, Jin S, Keenan MC, Marks
KM, Prins RM, Ward PS, Yen KE, Liau LM, Rabinowitz JD,
Cantley LC, Thompson CB, Vander Heiden MG, and Su SM:
Cancer-associated IDH1 mutations produce 2-hydroxyglutarate. Nature 2009;462:739–744.
2. Jin G, Reitman ZJ, Duncan CG, Spasojevic I, Gooden DM,
Rasheed BA, Yang R, Lopez GY, He Y, McLendon RE,
Bigner DD, and Yan H: Disruption of wild-type IDH1 suppresses D-2-hydroxyglutarate production in IDH1-mutatedgliomas. Cancer Res 2013;73:496–501.
3. Ward PS, Lu C, Cross JR, Abdel-Wahab O, Levine RL,
Schwartz GK, and Thompson CB: The potential for isocitrate
dehydrogenase mutations to produce 2-hydroxyglutarate
depends on allele specificity and subcellular compartmentalization. J Biol Chem 2013;288:3804–3815.
4. Lu C, Ward PS, Kapoor GS, Rohle D, Turcan S, AbdelWahab O, Edwards CR, Khanin R, Figueroa ME, Melnick A,
Wellen KE, O’Rourke DM, Berger SL, Chan TA, Levine RL,
Mellinghoff IK, and Thompson CB: IDH mutation impairs
histone demethylation and results in a block to cell differentiation. Nature 2012;483:474–478.
5. Turcan S, Rohle D, Goenka A, Walsh LA, Fang F, Yilmaz E,
Campos C, Fabius AW, Lu C, Ward PS, Thompson CB,
Kaufman A, Guryanova O, Levine R, Heguy A, Viale A,

OGASAWARA ET AL.
Morris LG, Huse JT, Mellinghoff IK, and Chan TA: IDH1
mutation is sufficient to establish the glioma hypermethylator phenotype. Nature 2012;483:479–483.
6. Rohle D, Popovici-Muller J, Palaskas N, Turcan S, Grommes
C, Campos C, Tsoi J, Clark O, Oldrini B, Komisopoulou E,
Kunii K, Pedraza A, Schalm S, Silverman L, Miller A, Wang
F, Yang H, Chen Y, Kernytsky A, Rosenblum MK, Liu W,
Biller SA, Su SM, Brennan CW, Chan TA, Graeber TG, Yen
KE, and Mellinghoff IK: An inhibitor of mutant IDH1 delays
growth and promotes differentiation of glioma cells. Science
2013;340:626–630.
7. Wang F, Travins J, DeLaBarre B, Penard-Lacronique V,
Schalm S, Hansen E, Straley K, Kernytsky A, Liu W, Gliser
C, Yang H, Gross S, Artin E, Saada V, Mylonas E, Quivoron
C, Popovici-Muller J, Saunders JO, Salituro FG, Yan S,
Murray S, Wei W, Gao Y, Dang L, Dorsch M, Agresta
S, Schenkein DP, Biller SA, Su SM, de Botton S, and Yen KE:
Targeted inhibition of mutant IDH2 in leukemia cells induces cellular differentiation. Science 2013;340:622–626.
8. Yan H, Parsons DW, Jin G, McLendon R, Rasheed BA, Yuan
W, Kos I, Batinic-Haberle I, Jones S, Riggins GJ, Friedman H,Friedman A, Reardon D, Herndon J, Kinzler KW, Velculescu
VE, Vogelstein B, and Bigner DD: IDH1 and IDH2 mutationsin gliomas. N Engl J Med 2009;360:765–773.
9. Paschka P, Schlenk RF, Gaidzik VI, Habdank M, Kronke J,
Bullinger L, Spath D, Kayser S, Zucknick M, Gotze K, Horst
HA, Germing U, Dohner H, and Dohner K: IDH1 and IDH2
mutations are frequent genetic alterations in acute myeloid
leukemia and confer adverse prognosis in cytogeneticallynormal acute myeloid leukemia with NPM1 mutation
without FLT3 internal tandem duplication. J Clin Oncol
2010;28:3636–3643.
10. Hartmann C, Meyer J, Balss J, Capper D, Mueller W,
Christians A, Felsberg J, Wolter M, Mawrin C, Wick W,
Weller M, Herold-Mende C, Unterberg A, Jeuken JW, Wesseling P, Reifenberger G, and von Deimling A: Type andfrequency of IDH1 and IDH2 mutations are related to astrocytic and oligodendroglial differentiation and age: a study of
1,010 diffuse gliomas. Acta Neuropathol 2009;118:469–474.
11. Kato Y, Jin G, Kuan CT, McLendon RE, Yan H, and Bigner
DD: A monoclonal antibody IMab-1 specifically recognizes
IDH1R132H, the most common glioma-derived mutation.
Biochem Biophys Res Commun 2009;390:547–551.
12. Kato Y, Natsume A, and Kaneko MK: A novel monoclonal antibody GMab-m1 specifically recognizes IDH1R132G mutation. Biochem Biophys Res Commun 2013;432:
564–567.
13. Kato Y, and Kaneko MK: Generation of a novel monoclonal
antibody WMab-1 specific for IDH2-R172W mutation. Biochem Biophys Res Commun 2013;433:374–378.
14. Kaneko MK, Tsujimoto Y, Hozumi Y, Goto K, and Kato Y:
Novel monoclonal antibodies GMab-r1 and LMab-1 specifically recognize IDH1-R132G and IDH1-R132L mutations.
Monoclon Antib Immunodiagn Immunother 2013;32:224–228.
15. Kaneko MK, Tian W, Takano S, Suzuki H, Sawa Y, Hozumi
Y, Goto K, Yamazaki K, Kitanaka C, and Kato Y: Establishment of a novel monoclonal antibody SMab-1 specific for
IDH1-R132S mutation. Biochem Biophys Res Commun 2011;
406:608–613.
16. Kaneko MK, Morita S, Tsujimoto Y, Yanagiya R, Nasu K,
Sasaki H, Hozumi Y, Goto K, Natsume A, Watanabe M,
Kumabe T, Takano S, and Kato Y: Establishment of novel
monoclonal antibodies KMab-1 and MMab-1 specific for IDH2
mutations. Biochem Biophys Res Commun 2013;432:40–45.

MULTI-SPECIFIC MAb MsMab-2 AGAINST IDH1/2 MUTATIONS
17. Takano S, Kato Y, Yamamoto T, Kaneko MK, Ishikawa E,
Tsujimoto Y, Matsuda M, Nakai K, Yanagiya R, Morita S,
Tsuboi K, and Matsumura A: Immunohistochemical detection of IDH1 mutation, p53, and internexin as prognostic
factors of glial tumors. J Neurooncol 2012;108:361–373.
18. Kaneko M, Ogasawara S, and Kato Y: Establishment of anovel multi-specific monoclonal antibody MsMab-1 recognizing both IDH1 and IDH2 mutations. Tohoku J Exp Med
2013;230:103–109.
19. Liu X, Kato Y, Kaneko MK, Sugawara M, Ogasawara S,
Tsujimoto Y, Naganuma Y, Yamakawa M, Tsuchiya T, andTakagi M: Isocitrate dehydrogenase 2 mutation is a frequent
event in osteosarcoma detected by a multi-specific monoclonal antibody MsMab-1. Cancer Med in press: DOI:
10.1002/cam4.149.

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Address correspondence to:
Dr. Yukinari Kato
Department of Regional Innovation
Tohoku University Graduate School of Medicine
2-1 Seiryo-machi
Aoba-ku, Sendai
Miyagi 980-8575
JapanE-mail: yukinari-k@bea.hi-ho.ne.jp
yukinarikato@med.tohoku.ac.jp
Received: July 9, 2013
Accepted: July 29, 2013