Related Experiment Video
Updated: Aug 11, 2026
04:32
A Uniform Shear Assay for Human Platelet and Cell Surface Receptors via Cone-plate Viscometry
Published on: June 5, 2019
A humanized antibody specific for the platelet integrin gpIIb/IIIa
Journal of Immunology (Baltimore, Md. : 1950)
|March 15, 1994
Summary
Humanizing the C4G1 antibody for treating thrombosis maintained its binding affinity and ability to inhibit platelet aggregation. This engineered antibody and its fragments show promise for antithrombotic therapies.
Area of Science:
- Immunology
- Biochemistry
- Pharmacology
Background:
- The C4G1 murine monoclonal antibody targets the platelet glycoprotein IIb/IIIa (gpIIb/IIIa) integrin.
- This integrin plays a crucial role in platelet aggregation and thrombosis.
- Humanization of antibodies is a key strategy for developing therapeutic agents with reduced immunogenicity.
Purpose of the Study:
- To humanize the C4G1 murine monoclonal antibody for potential therapeutic applications in thrombosis-related disorders.
- To assess the binding affinity and functional activity of the humanized antibody and its fragments.
- To develop genetic constructs for producing Fab and F(ab')2 fragments of the humanized C4G1 antibody.
Main Methods:
- Cloning and sequencing of variable regions from C4G1 hybridoma light and heavy chains.
- Construction of humanized C4G1 antibody (IgG1 isotype) using complementarity-determining regions from C4G1 and human framework/constant regions.
- Utilizing a computer model to optimize the human framework sequence for homology.
- Development of genetic constructs for producing Fab and F(ab')2 fragments.
Main Results:
- Humanized C4G1 IgG1, Fab, and F(ab')2 fragments demonstrated equivalent binding affinities to the murine antibody.
- No loss of binding affinity was observed during the humanization process.
- The humanized antibody and its fragments effectively inhibited platelet aggregation in vitro.
- Inhibition of fibrinogen binding to gpIIb/IIIa was also observed in vitro.
Conclusions:
- The humanization process successfully retained the binding affinity and functional activity of the C4G1 antibody.
- Humanized C4G1 antibody and its fragments are viable candidates for antithrombotic therapies.
- These findings support the potential clinical utility of humanized C4G1 for managing thrombosis.
Related Concept Videos
01:10Integrins
Animal and protozoan cells do not have cell walls to help maintain shape and provide structural stability. Instead, these eukaryotic cells secrete a sticky mass of carbohydrates and proteins into the spaces between adjacent cells. This network of proteins and molecules is called an extracellular matrix or ECM.
Some ECM proteins assemble into a basement membrane to which the remaining components adhere. Proteoglycans typically form the bulk of the ECM while fibrous proteins, like collagen,...
Some ECM proteins assemble into a basement membrane to which the remaining components adhere. Proteoglycans typically form the bulk of the ECM while fibrous proteins, like collagen,...
01:15Activation of Integrins
Integrins bind ligands and transmit information from outside the cell to inside or vice-versa through an "outside-in signaling" or "inside-out signaling."
In "outside-in signaling," external factors in the extracellular space bind to exposed ligand binding sites on integrins. This causes the inactive protein to undergo a conformational change to become active. Integrins are often clustered on the cell membrane. Repetitive and regularly spaced ligand binding events provide an effective stimulus.
In "outside-in signaling," external factors in the extracellular space bind to exposed ligand binding sites on integrins. This causes the inactive protein to undergo a conformational change to become active. Integrins are often clustered on the cell membrane. Repetitive and regularly spaced ligand binding events provide an effective stimulus.
01:17Intracellular Signaling Affects Focal Adhesions
Integrins act both as extracellular input receivers and as intracellular processing activators. As their name suggests, integrins are entirely integrated into the membrane structure. Their hydrophobic membrane-spanning regions interact with the phospholipid bilayer's hydrophobic region. These membrane receptors provide extracellular attachment sites for effectors like hormones and growth factors. They activate intracellular response cascades when their effectors are bound and active.
Some...
Some...