Advances in Bioscience and Biotechnology, 2013, 4, 18-23 ABB http://dx.doi.org/10.4236/abb.2013.49A003 Published Online September 2013 (http://www.scirp.org/journal/abb/) Carbohydrate-associated epitope-based anti-cancer drugs and vaccines* Gregory Lee1,2, Cheng-Yuan Huang2, Song-Nan Chow3, Chin-Hsiang Chien4 1UBC Center for Reproductive Health, University of British Columbia, Vancouver, Canada 2Vancouver BioTech Ltd., Vancouver, Canada 3Department of Obstetrics/Gynecology, National Taiwan University Hospital, Taipei, Chinese Taipei 4Institute of Biochemistry and Molecular Biology, National Yang Ming University, Taipei, Chinese Taipei Email: cyglee@yahoo.com Received 27 June 2013; revised 28 July 2013; accepted 15 August 2013 Copyright © 2013 Gregory Lee et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. ABSTRACT RP215 is one of the three thousand monoclonal anti- bodies (Mabs) which were generated against the OC- 3-VGH ovarian cancer cell line. RP215 was shown to react with a carbohydrate-associated epitope located specifically on glycoproteins, known as CA215, from cancer cells. Further molecular analysis by matrix adsorption laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) revealed that CA215 consists mainly of immunoglobulin super-fa- mily (IgSF) proteins, including immunoglobulins, T- cell receptors, and cell adhesion molecules, as well as several other unrelated proteins. Peptide mappings and glycoanalysis were performed with CA215 and revealed high-mannose and complex bisecting struc- tures with terminal sialic acid in N-glycans. As many as ten O-glycans, which are structurally similar to those of mucins, were also identified. In addition, two additional O-linked glycans were exclusively detected in cancerous immunoglobulins but not in normal B cell-derived immunoglobulins. Immunizations of mice with purified CA215 resulted in the predominant generation of RP215-related Mabs, indicating the immunodominance of this carbohydrate-associated epitope. Anti-idiotype (anti-id) Mabs of RP215, which were generated in the rat, were shown to contain the internal images of the carbohydrate-associated epi- tope. Following immunizations of these anti-id Mabs in mice, the resulting anti-anti-id (Ab3) responses in mice were found to be immuno logically similar to that of RP215. Judging from these observations, anti-id Mabs, which carry the internal image of the RP215- specific epitope, may be suitable candidates for anti- cancer vaccine development in humans. Keywords: Anti-Cancer Drugs; Anti-Cancer Vaccines; Anti-Idiotype; CA215; Carbohydrate-Associated Epitope; Immunodominance; RP215 1. INTRODUCTION Among the monoclonal antibodies (Mabs) which were generated against the OC-3-VGH ovarian cancer cell line, RP215 was shown to react with a carbohydrate-associ- ated epitope detected in cancerous glycoproteins, known as CA215. CA215 consists mainly of immunoglobulin superfamily (IgSF) proteins, including antigen receptors such as immunoglobulins, T-cell receptors, and several other related molecules, as well as unrelated mucins [1]. During the last decade, efforts have been made to char- acterize RP215 Mab and its cognate antigen, CA215. Cancerous immunoglobulins are the predominant mole- cules among CA215 that are recognized by RP215 through this specific carbohydrate-associated epitope [2]. Several experimental observations led us to conclude that the RP215-specific epitope in CA215 is carbohy- drate-associated. For example, a significant loss of RP- 215 epitope activity was observed when CA215 was treated with mild sodium periodate solution (10 - 100 mM) at neutral pH, extreme heat (e.g. 100˚C for 5 min), culturing of cancer cells in serum-free medium, or incu- bation at extreme pH (≤ 2.0 or ≥12.0) [2-4]. This is in contrast to normal human immunoglobulin G (IgG), of which the immunoactivity remained stable under the above conditions [2-4]. The ability of cancer cells to express immunoglobulins has been known for decades [5]. These cancerous im- munoglobulins have been found to be essential for the growth/proliferation of cancer cells [4,6]. With RP215 as the unique immunoprobe, numerous biological and im- munological studies were performed to explore the mechanisms of the action of cancerous immunoglobulins. *Conflict of interest: Gregory Lee is a co-founder of Vancouver Bio- Tech Ltd. OPEN ACCESS
G. Lee et al. / Advances in Bioscience and Biotechnology 4 (2013) 18-23 19 A significant progress has been made regarding our cur- rent understanding of cancer cell-expressed immu- noglobulins and their potential roles [7]. By means of terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) apoptosis assays, it was clearly dem- onstrated that RP215 or antibodies against immunog- lobulins or T-cell receptors, induced apoptosis in all studied cultured cancer cells, irrespective of their tissue origins [8]. By immunohistochemical studies, immu- noglobulins with the RP215 epitope can be readily de- tected on the surface of cancer cells [9]. Consequently, complement-dependent cytotoxicity (CDC) reactions can also be induced by antibodies against a variety of differ- ent classes or subclasses of immunoglobulins, including IgG, immunoglobulin M (IgM), immunoglobulin A (IgA), λ light chain or κ light chain [4,8]. CDC reactions can also be induced similarly with RP215 [8,9]. This led us to suggest the possibility that both RP215 and anti-anti- gen receptor antibodies are involved in affecting similar gene regulation patterns within cancer cells. This was indeed the case when gene regulation studies were per- formed with more than a dozen selected genes which are essential for the growth and proliferation of cancer cells. Excellent correlations were obtained between the gene regulation patterns of these selected genes and treatment with RP215 or anti-antigen receptors [7]. Furthermore, both RP215 and anti-antigen receptors exhibited simi- larly strong influences on the gene expressions of toll- like receptors [7, 10]. In particular, additional gene regu- lation studies revealed that genes of selected toll-like receptors, TLR-2, TLR-3, TLR-4, and TLR-9, were sig- nificantly affected by RP215 and antibodies against anti- gen receptors [7]. Since toll-like receptors are key com- ponents of cellular innate immunity, this observation strongly suggests the involvement of cancerous immu- noglobulins or antigen receptors in the innate immune system of cancer cells [7,10]. Peptide mapping and glycoanalysis of purified CA215 were performed in an attempt to elucidate the molecular structure of the carbohydrate-associated epitope recog- nized by RP215 [1] and are highlighted in this review. In addition, the immunological nature of RP215-specific epi- tope was also investigated through studies of more anti- CA215 Mabs and anti-idiotype (anti-id) Mabs against RP215. The possibility of using carbohydrate epitope- based anti-cancer vaccines was evaluated based on these experimental observations [11]. 2. BIOCHEMICAL AND IMMUNOLOGICAL NATURE OF THE CARBOHYDRATE-ASSOCIATED EPITOPE 2.1. Structural Analysis of Carbohydrate Epitope Recognized by RP215 Efforts were made to identify and elucidate the structures of the RP215-specific carbohydrate-associated epitope. These included structural analysis of the N-linked and O-linked oligosaccharides in CA215 [1]. Initially, the shed media from two cultured cancer cell-lines, OC-3- VGH (ovarian) and C-33A (cervical), were collected se- parately and purified for CA215 by RP215-affinity chro- matography. To obtain affinity-purified cancerous IgG (designated as CA215-D), affinity-purified CA215 was further subjected to purification by anti-human IgG af- finity chromatography (designated as CA215-D). The af- finity-purified CA215 samples were desalted and clean- ed of borate, permethylated, and analyzed either by nano spray ionization-linear ion trap mass spectrometry (NSI- LTQ/MSn) or by matrix-assisted laser desorption/ ioni- zation time-of-flight mass spectrometry (MALDI-TOF MS). N-linked glycan profiling revealed unusually high mannose structures, as well as terminal N-glycolylnu- eraminic acids, both of which do not appear in normal human IgG [12]. On the other hand, several cancer-asso- ciated mucin-type O-glycans were found in CA215, in- cluding core 1 to 3 based structures such as sialyl-T, sia- lyl-Tn, and di-sialyl-T antigens, and Lewis antigens such as Lea, Leb, Lex, SLex, and Ley. The potential pathways for the synthesis of the carbohydrate-associated epitope recognized by RP215 have been elucidated by the studies of glycosyl-transferases which are involved in O-glycan synthesis (Gao. Y. and Brockhausen, I., personal com- munication). Results of the comparative profiles of per- methylated O-linked glycans from five different CA215 samples are presented in Table 1. From the structural analysis of O-linked oligosaccharides identified for CA- 215, it can be demonstrated that cancerous IgG (CA215D) can be attached with two different distinct O-linked oli- gosaccharides: GalNAc1 Gal1 NeuAc1 and GalNAc1 Gal1 NeuAc2. These two O-linked oligosaccharides are unique to cancerous IgG, but absent in normal human IgG [12]. It remains to be elucidated to see if these two O-linked oligosaccharides are structurally linked to the RP215- specific carbohydrate-associated epitope. Following further analysis with glycosylation site pep- tide mapping, the potential N-glycosylation and O-gly- cosylation sites along the peptides sequences were iden- tified by Protein BLAST service. Among the ten glyco- peptides which were detected from CA215, eight were shown to be homologous to the Fab and/or Fc fragments of human immunoglobulin heavy chains. All the analyti- cal results of the ten glycopeptides are summarized in Table 2. These experimental analyses strongly suggested that immunoglobulin heavy chains are the predominant molecular species in CA215 [1,2]. In addition, the RP215- specific epitope activity of CA215 was found to be pH-dependent. At pH 12, deglycosylation of CA215 may esult in loss of RP215 epitope activity. r Copyright © 2013 SciRes. OPEN ACCESS
G. Lee et al. / Advances in Bioscience and Biotechnology 4 (2013) 18-23 Copyright © 2013 SciRes. 20 Table 1. Comparative profiles of permethylated O-linked glycans of human IgG and five different CA215 samples. Observed Mass Proposed Sample ID m/z [M + Na]+ structure Structure CA215 (lots: A, B, and C)a 534 GalNAc1Gal1 CA215 (lots: A and B) 708 GalNAc1Gal1Fuc1 CA215 (lots: A, B, D, C, E, and F)b896 GalNAc1Gal1NeuAc1 CA215 (lots: C, E, and F) 926 GalNAc1Gal1NeuGc1 CA215C 940c GalNAc1GlcNAc1NeuAc1 CA215(lots: A, B, and C) 1140 GalNAc1GlcNAc1Gal1NeuAc1 CA215 (lots: C, D, E, and F) 1257 GalNAc1Gal1NeuAc2 CA215 (lots: C, E, and F) 1317 GalNAc1Gal1NeuGc2 CA215 (lots: A, B, C, E, and F) 1345 GalNAc1GlcNAc1Gal2NeuAc1 CA215 (lots: C, E, and F) 1375 GalNAc1GlcNAc1Gal2NeuGc1 aCA215 lots A, B and C were from OC-3-VGH ovarian cancer cells (CA215-OC-3) lots A and B were obtained through acid elution, whereas lots C, D, E and F were obtained through elution with 3M urea. bLot CA215D was obtained by an additional purification of urea-eluted CA215 (S15K-100425) with goat anti-human. IgG affinity column followed by the same analysis (CA215D is designated as affinity-purified cancerous IgG). CA215 lots E and F were from C-33A cervical cancer cells (CA215-C33A). cDetected by MALDI-TOF MS method but not found by NSI-MS method. dN-acetylgalactosamine (□), N-acetylglucosamine (■), Fucose (▲), Galactose (●), N-acetylneuraminic acid (♦) and N-glycolylneuraminic acid (♦). [Obtained from reference #1 with per- mission]. Table 2. N-linked and O-linked glycosylation site mappings of CA215. Fc refers to the constant region of the immunoglobulins. Fab represents the variable region of the immunoglobulins. Lot CA215C (urea-eluted) was used for this analysis. The source protein BLAST service was: http://blast.ncbi.nlm.nih.gov/Blast.cgi. Accession number Peptide detecteda Peptide sequence homology of proteins (%) I. CAC12842.1 1. EEQFNSTFR Immunoglobulin heavy chain (Fc) (100%) II. CAA04843.1 2. EEQFNSTYR Immunoglobulin heavy chain (Fc) (100%) III. AAB60643.2 3. LSVPTSEWQR Cathepsin S (100%) IV. AAK68690.1 4. FTCLATNDAGDSSK Hemicentin (100%) Titin (100%) Palladin isoform 4 (92%) LRN4 (78%) (IgSF proteins) V. AAD38158.1 5. DTLMISR Immunoglobulin heavy chain (Fc) (100%) VI. AAC39746.2 6. GYLPEPVTVTWNSGTLTNGVR Immunoglobulin heavy chain (Fab) (90%) VII. AAN76042.1 7. SVSLTCMINGFYPSDISVEWEK Immunoglobulin heavy chain (Fc) (90%) VIII. CAJ75462.1 8. QSSGLYSLSSVVSVTSSSQPVTCNV Immunoglobulin heavy chain (Fab and Fc) (100%) IX. ABY48864.2 9. VYTMGPPREELSSR Immunoglobulin heavy chain (Fc) (98%) IgA variable region (89%) IgM (98%) X. NP_001139647.1 10. TFPSVR Zinc finger protein 414 isoform I (100%) Forkhead box protein C2 (100%) Immunoglobulin heavy chain variable region (83%) a ; Bold letters indicate glycosylation sites [Obtained from reference #1 with permission]. OPEN ACCESS
G. Lee et al. / Advances in Bioscience and Biotechnology 4 (2013) 18-23 21 2.2. Molecular and Immuno-Characteristics of Cancerous Immunoglobulins The molecular and immunological nature of cancerous immunoglobulins was further investigated initially through reverse transcription polymerase chain reaction (RT-PCR) to determine the primary structures of cancerous IgG and IgA at the DNA and protein levels. In the constant re- gions of the heavy chains, the IgG and IgA detected in cancer cells were identical to those of normal human B cells with homology greater than 98% [2,13]. Studies were conducted to investigate if the glycosylations in cancerous immunoglobulins have any alterations in their biochemical and immunological properties as compared to those of normal human IgG. As stated previously, cancerous IgG was isolated by two-step affinity chroma- tography from the OC-3-VGH ovarian cancer cell line. Unexpectedly, the isolated cancerous IgG (CA215D in Table 1) exhibits extremely low immunoactivity when compared to that of normal human IgG. Apparently, the aberrant glycosylations have altered the tertiary structure of the cancerous IgG and subsequently its immunological properties [3]. 2.3. Immunodominance of RP215-Specific Epitope in CA215 Attempts were made to generate additional Mabs against affinity-purified CA215. Some of the epitopes recogni- zed by the new Mabs were conformational, while others were linear, similar to that recognized by RP215. When compared with Mabs against CA215, the amino acid sequence homology to RP215’s Fab regions ranged from 100% to 65% for the five generated Mabs which were designated as RCA-10, RCA-100, RCA-104, RCA-110 and RCA-111, respectively [14]. Unexpectedly, all of the five generated Mabs were shown to recognize epitopes similar or identical to the RP215-specific epitope. All of the generated RCA Mabs and RP215 were shown to induce apoptosis and CDC of cancer cells in culture [14]. These Mabs were categorized into three distinct groups according to their sequence homology and epitope spe- cificity. All of these Mabs could be paired with RP215 in a typical sandwich enzyme immunoassay [14]. These ex- perimental observations strongly suggest the immunodo- minance of the RP215-specific carbohydrate-associated epitope. The immunological basis of the immunodomi- nance of RP215-specific “sugar” epitope remains to be explained. It also remains to be demonstrated if differen- tial anti-cancer efficacy exists among the three distinct groups of these biosimilar anti-CA215 Mabs. Due to the existence of the immunodominance of the RP215-asso- ciated carbohydrate epitope, we are encouraged to use these RP215 unique epitope(s) or glycolpeptide com- ponents for the development of anti-cancer vaccines or antibody-based anti-cancer drugs in humans [14]. 2.4. Anti-Idiotype Monoclonal Antibodies against RP215 as Anti-Cancer Vaccines RP215 was shown to inhibit the growth of a variety of cancer cells in vitro and in vivo [9,11]. Anti-idiotype (anti-id) Mabs against RP215 were generated in the rat and characterized for future development of epitope- specific anti-cancer vaccines in humans. These rat anti-id Mabs were generated by using F(ab’)2 fragments of RP215 as the immunogen. Anti-id Mabs were then util- ized for subsequent immunizations in mice to induce anti-anti-id (Ab3) antibody responses. By using TUNEL apoptosis assay, both RP215 and Ab3 were shown to induce apoptosis in cultured cancer cells [4, 7-9,11,13]. Ab3 and RP215 were shown to react similarly with can- cer cells from cell lines of different human tissue origins by immunohistochemical staining assay and by Western blot assay [15]. Results of this study suggest that anti-id Mabs bear the properties of the internal image of RP215-specific car- bohydrate-associated epitope [11]. Ab3 immune respon- ses can be induced upon immunization of rat anti-id Mab in mice. Ab3 were shown to have immunological proper- ties similar to that of RP215 in terms of the efficacy to induce apoptosis to cancer cells. Therefore, anti-id Mabs against RP215 could be a good candidate for the devel- opment of anti-cancer vaccines in the future [11]. 3. DISCUSSION When RP215 Mab was initially generated against the OC-3-VGH ovarian cancer cell extract in 1987, it was initially used as for diagnostic applications to monitor serum levels of CA215, a pan cancer biomarker among cancer patients [16,17]. It was later shown that the epi- tope recognized by RP215 was carbohydrate-associated and reacts with CA215, which consists mainly of IgSF proteins. Cancerous immunoglobulins are widespread among all cancer cells and have been demonstrated to be essential for the growth/proliferation of cancer cells [4,8,11]. Therefore, RP215 may become a unique probe to target surface bound immunoglobulins and serve as antibody-based anti-cancer drugs for therapeutic applica- tions [11]. In this review, efforts were made to summa- rize the characteristics of this carbohydrate-associated “sugar” epitope recognized by RP215 Mab, through pep- tide mappings and glycoanalysis, demonstration of im- munodominance, and generation of anti-id Mabs against RP215 [1,11]. The progress of this research is briefly described in this review for the potential development of “sugar” epitope-based anti-cancer vaccines. With RP215 and anti-human IgG as the affinity ligands in two-step immunoaffinity chromatography, cancerous IgG was Copyright © 2013 SciRes. OPEN ACCESS
G. Lee et al. / Advances in Bioscience and Biotechnology 4 (2013) 18-23 22 purified from the shed media of two separate cancer cell lines, OC-3-VGH (ovary) and C33A (cervix). Two O- linked oligosaccharides were identified from the purified cancerous IgG, but were absent in normal human IgG [1,12]. It was assumed that these O-linked oligosaccha- rides may be related to the RP215-specific carbohydra- te-associated epitope in cancerous IgG. However, this assumption can be verified only when the primary struc- ture of the carbohydrate moiety is completely elucidated [1]. The immunodominance of the RP215-specific carbo- hydrate-associated epitope is an interesting phenomenon [14,18]. When mixtures of purified CA215 glycoproteins, each of which carries the RP215-specific epitope, were used as immunogen to generate Mabs, all the recovered clones were found to secrete Mabs recognizing epitope(s) similar to that of RP215 [14]. This observation indicates the immunodominance of the RP215-specific “sugar” epitope, which may have potential application in future cancer vaccine development [14,18]. Attempts were made to demonstrate the generations of rat generated anti-id Mabs against RP215 for cancer vac- cine development [11]. Following generations of mono- clonal anti-id antibodies in the rat, anti-id antibodies can be mass-produced and serve as the immunogen in ani- mals or humans to induce Ab3 responses. Experimental evidence has indicated that Ab3 antiserum is similar to RP215 in recognizing the RP215-specific epitope of CA215, with the anti-cancer efficacy demonstrated in our studies, such as through induced apoptosis assays [4,11]. Therefore, monoclonal anti-id antibodies can serve as the immunogen for anti-cancer vaccinations to induce Ab3 responses in humans for the therapeutic applications of human cancer [11]. Cancer treatment with anti-id anti- bodies through active immunizations in vaccinations has been reported previously for leukemia, but with limited efficacy [19]. Vaccination can elicit strong and specific humoral responses to relevant tumor associated antigens, but clinical implications of these results remain fully elucidated. Judging from numerous on-going preclinical studies, the RP215-specific carbohydrate-associated epi- tope in cancerous immunoglobulins appears to be a suit- able candidate for cancer vaccine development [8,11]. Furthermore, the carbohydrate-associated epitope-based anti-cancer vaccines can potentially target cancer cells of many tissue origins in humans [11]. 4. CONCLUSION There is no doubt that cancerous immunoglobulins play an important role in the growth/proliferation of cancer cells. The carbohydrate-associated epitope(s) on CA215 exhibit their universal expression in different cancer cell lines and the unique characteristic of immunodominance. The experimental results also suggested the concept of developing a vaccine based on either a humanized RP215 Mab or its internal image (anti-id Mab). More effort is still required to elucidate the structures of the carbohy- drate-associated epitope on CA215. These updated ex- perimental observations should advance our current un- derstanding in cancer immunology and provide a novel strategy for the development of cancer vaccines. 5. ACKNOWLEDGEMENTS This work was supported in parts by NRC-IRAP program (#794354) of Canada. Proof readings and preparations of this manuscript by summer research student, Suefay Liu of McGill University, are acknowledged. REFERENCES [1] Lee, G. and Azadi, P. (2012) Peptide mapping and gly- coanalysis of cancer cell—expressed glycoproteins CA215 recognized by RP215 monoclonal antibody. Journal of Carbohydrate Chemistry, 31, 10-30. doi:10.1080/07328303.2011.626544 [2] Lee, G., Laflamme E., Chien, C.-H. and Ting, H.H. (2008) Molecular identity of a pan cancer marker, CA215. Can- cer Biology and Therapy, 7, 2007-2014. http://www.landesbioscience.com/journals/cbt/article/698 4/ doi:10.4161/cbt.7.12.6984 [3] Lee, G., Cheung, A.P., Li, B., Ge, B. and Chow, P.-M. (2012) Molecular and immuno-characteristics of immu- noglobulin-like glycoproteins in cancer cell-expressed biomarker, CA215. Immunological Investigations, 41, 429-446. http://informahealthcare.com/doi/abs/10.3109/08820139. 2012.661007 doi:10.3109/08820139.2012.661007 [4] Lee, G. and Ge, B. (2010) Inhibition of in vitro tumor cell growth by RP215 monoclonal antibody and antibodies raised against its anti-idiotype antibodies. Cancer Immu- nology, Immunotherapy, 59, 1347-1356. doi:10.1007/s00262-010-0864-7 [5] Kimoto, Y. (1998) Expression of heavy-chain constant region of immunoglobulin and T-cell receptor gene tran- scripts in human non-hematopoietic tumor cell lines. Genes, Chromosomes and Cancer, 22, 83-86. doi:10.1002/(SICI)1098-2264(1998)22:1<83::AID-GCC1 2>3.0.CO;2-O [6] Qiu, X., Zhu, X., Zhang, L., Mao, Y., Zhang, J., Hao, P., et al. (2003) Human epithelial cancers secrete immu- noglobulin G with unidentified specificity to promote growth and survival of tumor cells. Cancer Research, 63, 6488-6495. http://cancerres.aacrjournals.org/content/63/19/6488.abstr act [7] Tang, Y., Zhang, H. and Lee, G. (2013) Similar gene regulation patterns for growth inhibition of cancer cells by RP215 or anti-antigen receptors. Journal of Cancer Science and Therapy, 5, 200-208. doi:10.4172/1948-5956.1000207 [8] Lee, G., Cheung, A., Ge, B., Zhu, M., Giolma, B., Li, B., et al. (2012) CA215 and GnRH receptor as targets for Copyright © 2013 SciRes. OPEN ACCESS
G. Lee et al. / Advances in Bioscience and Biotechnology 4 (2013) 18-23 Copyright © 2013 SciRes. 23 OPEN ACCESS cancer therapy. Cancer Immunology, Immunotherapy, 61, 1805-1817. [9] Lee, G., Zhu, M., Ge, B. and Potzold, S. (2012) Wide- spread expressions of immunoglobulin superfamily pro- teins in cancer cells. Cancer Immunology, Immunother- apy, 61, 89-99. doi:10.1007/s00262-011-1088-1 [10] Lee, G. and Liu, S. (2013) Roles of cancerous antigen receptors and CA215 in the innate immunity of cancer cells. Current Immunology Reviews, In press. [11] Lee, G., Cheung A.P., Ge B., Zhu M., Li, P.P., Hsu, E., et al. (2010) Monoclonal anti-idiotype antibodies against carbohydrate-associate epitope for anti-cancer vaccine de- velopment. Journal of Vaccines and Vaccination, 1, 1-7. [12] Arnold, J.N., Wormald, M.R., Sim, R.B., Rudd, P.M. and Dwek, R.A. (2007) The impact of glycosylation on the biological function and structure of human immuno- globulins. Annual Review of Immunology, 25, 21-50. doi:10.1146/annurev.immunol.25.022106.141702 [13] Lee, G. and Ge, B. (2009) Cancer cell expressions of immunoglobulin heavy chains with unique carbohy- drate-associated biomarker. Cancer Biomarkers, 5, 177- 188. [14] Lee, G., Zhu, M., Ge, B., Cheung, A.P., Chien, C.-H., Chow, S.-N., et al. (2012) Carbohydrate-associated im- munodominant epitope(s) of CA215. Immunological In- vestigations, 41, 317-336. http://informahealthcare.com/doi/abs/10.3109/08820139. 2011.633141 doi:10.3109/08820139.2011.633141 [15] Lee, G., Ge, B., Huang, T.-K., Zheng, G., Duan, J. and Wang, I.H.Y. (2009) Positive identification of CA215 pan cancer biomarker from serum specimens of cancer patients. Cancer Biomarkers, 6, 111-117. http://dx.doi.org/10.3233/CBM-2009-0134 [16] Lee, C.Y., Chen, K.W., Sheu, F.S., Tsang, A., Chao, K.C. and Ng, H.T. (1992) Studies of a tumor-associated anti- gen, COX-1, recognized by a monoclonal antibody. Can- cer Immunology, Immunotherapy, 35, 19-26. doi:10.1007/BF01741050 [17] Lee, G. (2009) Cancer cell-expressed immunoglobulins: CA215 as a pan cancer marker and its diagnostic applica- tions. Cancer Biomarkers, 5, 137-142. [18] Wilson, E.H. and Hunter, C.A. (2008) Immunodomi- nance and recognition of intracellular pathogens. Journal of Infectious Diseases, 198, 1579-1581. http://jid.oxfordjournals.org/content/198/11/1579.short doi:10.1086/593020 [19] Zhao, X., Singh, S., Pardoux, C., Zhao, J., His, E.D., Abo, A., et al. (2010) Targeting C-type lectin-like molecule-1 for antibody-mediated immunotherapy in acute myeloid leukemia. Haematologica, 95, 71-78. doi:10.3324/haematol.2009.009811
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