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Effect of a single amino acid mutation on the activating and immunosuppressive properties of a "humanized" OKT3 monoclonal antibody.
- Source :
-
Journal of immunology (Baltimore, Md. : 1950) [J Immunol] 1992 Jun 01; Vol. 148 (11), pp. 3461-8. - Publication Year :
- 1992
-
Abstract
- The binding specificity of the murine OKT3 has been transferred into a human antibody framework to reduce its immunogenicity. This "humanized" anti-CD3 mAb (gOKT3-5) was previously shown to retain, in vitro, all the properties of native OKT3, including T cell activation, which has been correlated, in vivo, with the severe side effects observed in transplant recipients after the first administration of the mAb. T cell activation is thought to be triggered by the cross-linking mediated by the antibodies between T cells and Fc receptor-bearing cells. In this study, we introduced a single amino acid mutation from a leucine to a glutamic acid at position 235 in the Fc receptor binding segment of the gOKT3-5 mAb to produce Glu-235 mAb. This mutation generated a 100-fold decrease in the affinity of the antibody for the Fc receptor on U937 cells, without affecting Ag binding. In parallel, we observed a marked reduction in the T cell activation triggered by the mAb (proliferation, cell surface expression of early activation markers including Leu 23 and IL-2R, and release of TNF-alpha, IFN-gamma, and granulocyte macrophage-CSF). In contrast, the mutated mAb retained suppressive properties similar to the gOKT3-5 mAb, as assessed by significant modulation of the T cell receptor complex and suppression of Ag-specific CTL activity. We conclude that this anti-CD3 mAb bearing a single amino acid mutation in its Fc portion retains important immunosuppressive properties, while exhibiting significantly less T cell activation than OKT3 in vitro. This drug might achieve potent immunosuppression while minimizing acute toxicity in vivo and thus be useful in transplantation as well as in autoimmune diseases.
- Subjects :
- Amino Acid Sequence
Animals
Antibody Affinity
Antigens, Differentiation metabolism
Binding Sites, Antibody
CD3 Complex
Granulocyte-Macrophage Colony-Stimulating Factor biosynthesis
Humans
Immunosuppression Therapy
In Vitro Techniques
Interferon-gamma biosynthesis
Lymphocyte Activation
Mice
Molecular Sequence Data
Muromonab-CD3 metabolism
Receptors, Fc metabolism
Receptors, IgG
Recombinant Fusion Proteins
T-Lymphocytes, Cytotoxic immunology
Tumor Cells, Cultured
Tumor Necrosis Factor-alpha biosynthesis
Antigens, Differentiation, T-Lymphocyte immunology
Muromonab-CD3 chemistry
Receptors, Antigen, T-Cell immunology
Subjects
Details
- Language :
- English
- ISSN :
- 0022-1767
- Volume :
- 148
- Issue :
- 11
- Database :
- MEDLINE
- Journal :
- Journal of immunology (Baltimore, Md. : 1950)
- Publication Type :
- Academic Journal
- Accession number :
- 1534096