reported that analysis of glycopeptides by MALDI-TOF may overestimate low abundant truncated oligosaccharides due to in-source frag-mentation of the abundant oligosaccharide struc-tures.Therefore,for recombinant monoclonal antibody characterization,parallel rigorous con-trols are very important.
Characterization and a thorough understand-ing of the heterogeneity of monoclonal antibodies can be very challenging.However,the informa-tion is invaluable to understanding structure and stability of the molecule in order to engineer better molecules with good efficacy and safety. ACKNOWLEDGMENTS
The authors would like to thank Lyman G.Armes for critical review of the manuscript,and Czeslaw H.Radziejewski,Gary J.Welch and Peter Moesta for their support.
REFERENCES
1.Askonas BA.1961.A study on globulin formation
by plasma-cell neoplasm(5563)transplantable in mice.Biochem J79:33–43.
2.Awdeh ZL,Askonas BA,Williamson AR.1967.The
homogeneous-gamma-G-immunoglobulin produced by mouse plasmacytoma5563and its subsequent heterogeneity in serum.Biochem J102:548–553.
3.Awdeh ZL,Williamson AR,Askonas BA.1969.
Heavy and light chains of a homogeneous immu-noglobulin-G.FEBS Lett5:275–278.
4.Awdeh ZL,Williamson AR,Askonas BA.1970.One
cell-one immunoglobulin.Origin of limited hetero-geneity of myeloma proteins.Biochem J116:241–248.
tner L,Albert L,Marshall T,Gambie M.
1980.Michroheterogeneity of serum myeloma immunoglobulins revealed by a technique of high resolution two-dimensional electrophoresis.Elec-trophoresis1:82–89.
6.Tracy RP,Currie RM,Kyle RA,Young DS.1982.
Two-dimensional gel electrophoresis of serum spe-cimens from patients with monoclonal gammopa-thies.Clin Chem28:900–907.
7.Jungbauer A,Tauer C,Wenisch E,Uhl K,Brunner
J,Purtscher M,Steindl F,Buchacher A.1990.
Isolation of isoproteins from monoclonal antibo-dies and recombinant proteins by chromatofocus-ing.J Chromatogr512:157–163.
8.Goldfarb MF.1992.Two-dimensional electro-
phoretic analysis of immunoglobulin patterns in monoclonal gammopathies.Electrophoresis13: 440–444.
9.Kaltenbrunner O,Tauer C,Brunner J,Jungbauer
A.1993.Isoprotein analysis by ion-exchange chro-
matography using a linear pH gradient combined with a salt gradient.J Chromatogr639:41–49. 10.Tissot JD,Hochstrasser DF,Spertini F,Schifferli
JA,Schneider P.1993.Pattern variations of poly-clonal and monoclonal immunoglobulins of differ-ent isotypes analyzed by high-resolution two-dimensional electrophoresis.Electrophoresis14: 227–234.
11.Ackermann M,Marx U,Jager V.1995.Influence of
cell-and Media-derived factors on the integrity of a human monoclonal antibody after secretion into serum-free cell culture supernatants.Biotechnol Bioeng45:97–106.
12.Takeo K,Suzuno R,Tanaka T,Nakamura K.1989.
Complete separation of anti-hapten antibodies by two-dimensional affinity electrophoresis.Electro-phoresis10:813–818.
13.Takeo K,Tanaka T,Nakamura K,Suzuno R.1989.
Studies on the heterogeneity of anti-hapten anti-bodies by means of two-dimensional affinity elec-trophoresis.Electrophoresis10:818–824.
14.Hamilton G.Robert RBC,Rodkey LS,1987.Qual-
ity control of murine monoclonal antibodies using isoelectric focusing affinity immunoblot analysis.
Hybridoma6:205–217.
15.Jungbauer A,Unterluggauer F,Uhl K,Buchacher
A,Steindl F,Pettauer D,Wenisch E.1988.Scaleup of monoclonal antibody purification using radial streaming ion exchange chromatography.Biotech-nol Bioeng32:326–333.
16.Sticherling M,Schroder JM,Christophers E.
1989.Production and characterization of monoclo-nal antibodies against the novel neutrophil activating peptide NAP/IL-8.J Immunol143: 1628–1634.
pton BJ,Gerald JS,Lowe DA,Elander RP.
1989.Micro isoelectric point heterogeneity of a murine monoclonal antibody(L6)originating from cell cultivation conditions.Biotechnol Tech3:349–354.
18.Grebenau RC,Goldenberg DM,Chang CH,Koch
GA,Gold DV,Kunz A,Hansen HJ.1992.Micro-heterogeneity of a purified IgG1due to asymmetric Fab glycosylation.Mol Immunol29:751–758. 19.Nakamura K,Mimura Y,Takeo K.1993.Immune
response to a hapten offluorescein isothiocyanate in a single mouse analyzed by two-dimensional affinity electrophoresis.Electrophoresis14:81–
87.
20.Nakamura K,Mimura Y,Tanaka T,Fujikura Y,
Takeo K.1993.Affinity maturation of anti-hapten antibodies in a single mouse analyzed by two-dimensional affinity electrophoresis.Electrophor-esis14:1338–1340.
21.Jiskoot W,Beuvery EC,de Koning AA,Herron JN,
Crommelin DJ.1990.Analytical approaches to the
DOI10.1002/jps JOURNAL OF PHARMACEUTICAL SCIENCES,VOL.97,NO.7,JULY2008
HETEROGENEITY OF MONOCLONAL ANTIBODIES2437