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Humanised IgG1 antibody variants targeting membrane-bound carcinoembryonic antigen by antibody-dependent cellular cytotoxicity and phagocytosis.
- Source :
- British Journal of Cancer; 11/17/2009, Vol. 101 Issue 10, p1758-1768, 11p, 1 Chart, 7 Graphs
- Publication Year :
- 2009
-
Abstract
- <bold>Background: </bold>The effect of glycoengineering a membrane specific anti-carcinoembryonic antigen (CEA) (this paper uses the original term CEA for the formally designated CEACAM5) antibody (PR1A3) on its ability to enhance killing of colorectal cancer (CRC) cell lines by human immune effector cells was assessed. In vivo efficacy of the antibody was also tested.<bold>Methods: </bold>The antibody was modified using EBNA cells cotransfected with beta-1,4-N-acetylglucosaminyltransferase III and the humanised hPR1A3 antibody genes.<bold>Results: </bold>The resulting alteration of the Fc segment glycosylation pattern enhances the antibody's binding affinity to the FcgammaRIIIa receptor on human immune effector cells but does not alter the antibody's binding capacity. Antibody-dependent cellular cytotoxicity (ADCC) is inhibited in the presence of anti-FcgammaRIII blocking antibodies. This glycovariant of hPR1A3 enhances ADCC 10-fold relative to the parent unmodified antibody using either unfractionated peripheral blood mononuclear or natural killer (NK) cells and CEA-positive CRC cells as targets. NK cells are far more potent in eliciting ADCC than either freshly isolated monocytes or granulocytes. Flow cytometry and automated fluorescent microscopy have been used to show that both versions of hPR1A3 can induce antibody-dependent cellular phagocytosis (ADCP) by monocyte-derived macrophages. However, the glycovariant antibody did not mediate enhanced ADCP. This may be explained by the relatively low expression of FcgammaRIIIa on cultured macrophages. In vivo studies show the efficacy of glycoengineered humanised IgG1 PR1A3 in significantly improving survival in a CRC metastatic murine model.<bold>Conclusion: </bold>The greatly enhanced in vitro ADCC activity of the glycoengineered version of hPR1A3 is likely to be clinically beneficial. [ABSTRACT FROM AUTHOR]
- Subjects :
- CARCINOEMBRYONIC antigen
PHAGOCYTOSIS
COLON cancer
GLYCOSYLATION
FLUORESCENCE microscopy
MACROPHAGES
GRANULOCYTE antigens
FLOW cytometry
RESEARCH
IMMUNOGLOBULINS
ANIMAL experimentation
RESEARCH methodology
MONOCLONAL antibodies
KILLER cells
CELL receptors
MEDICAL cooperation
EVALUATION research
COLORECTAL cancer
COMPARATIVE studies
GENETIC engineering
IMMUNITY
TUMOR antigens
CELL lines
GENETIC techniques
MICE
Subjects
Details
- Language :
- English
- ISSN :
- 00070920
- Volume :
- 101
- Issue :
- 10
- Database :
- Complementary Index
- Journal :
- British Journal of Cancer
- Publication Type :
- Academic Journal
- Accession number :
- 45092422
- Full Text :
- https://doi.org/10.1038/sj.bjc.6605355