Human monoclonal antibodies to sialyl-Lewisa (CA19.9) with potent CDC, ADCC, and antitumor activity Journal Article


Authors: Sawada, R.; Sun, S. M.; Wu, X.; Hong, F.; Ragupathi, G.; Livingston, P. O.; Scholz, W. W.
Article Title: Human monoclonal antibodies to sialyl-Lewisa (CA19.9) with potent CDC, ADCC, and antitumor activity
Abstract: Purpose: The carbohydrate antigen sialyl-Lewisa (sLe a), also known as CA19.9, is widely expressed on epithelial tumors of the gastrointestinal tract and breast and on small-cell lung cancers. Since over-expression of sLea appears to be a key event in invasion and metastasis of many tumors and results in susceptibility to antibody-mediated lysis, sLea is an attractive molecular target for tumor therapy. Experimental Design: We generated and characterized fully human monoclonal antibodies (mAb) from blood lymphocytes from individuals immunized with a sLea-KLH vaccine. Results: Several mAbs were selected based on ELISA and FACS including two mAbs with high affinity for sLea (5B1 and 7E3, binding affinities 0.14 and 0.04 nmol/L, respectively) and further characterized. Both antibodies were specific for Neu5Acα2-3Galβ1- 3(Fucα1-4)GlcNAcβ as determined by glycan array analysis. Complement-dependent cytotoxicity against DMS-79 cells was higher (EC 50 0.1 μg/mL vs. 1.7 μg/mL) for r7E3 (IgM) than for r5B1 (IgG1). In addition, r5B1 antibodies showed high level of antibody-dependent cell-mediated cytotoxicity activity on DMS-79 cells with human NK cells or peripheral blood mononuclear cells. To evaluate in vivo efficacy, the antibodies were tested in a xenograft model with Colo205 tumor cells engrafted into SCID (severe combined immunodeficient mice) mice. Treatment during the first 21 days with four doses of r5B1 (100 mg per dose) doubled the median survival time to 207 days, and three of five animals survived with six doses. Conclusion: On the basis of the potential of sLea as a target for immune attack and their affinity, specificity, and effector functions, 5B1and 7E3may have clinical utility. ©2011 AACR.
Keywords: cancer survival; controlled study; unclassified drug; human cell; drug efficacy; nonhuman; antineoplastic agent; mouse; animal experiment; animal model; in vivo study; antineoplastic activity; tumor xenograft; drug synthesis; monoclonal antibody; survival time; antibody specificity; tumor; antigen binding; lymphocyte; immunoglobulin g1 antibody; scid mouse; peripheral blood mononuclear cell; antibody affinity; antibody dependent cellular cytotoxicity; complement dependent cytotoxicity; tumor engraftment; immunoglobulin m antibody; glycan; monoclonal antibody ca19.9; n acetylglucosamine; sialyl lewis x antigen
Journal Title: Clinical Cancer Research
Volume: 17
Issue: 5
ISSN: 1078-0432
Publisher: American Association for Cancer Research  
Date Published: 2011-03-01
Start Page: 1024
End Page: 1032
Language: English
DOI: 10.1158/1078-0432.ccr-10-2640
PROVIDER: scopus
PMCID: PMC3074602
PUBMED: 21343375
DOI/URL:
Notes: --- - "Export Date: 23 June 2011" - "CODEN: CCREF" - "Source: Scopus"
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MSK Authors
  1. Feng Hong
    10 Hong
  2. Govindaswami Ragupathi
    144 Ragupathi
  3. Xiaohong Wu
    6 Wu