Genetic engineering antibody technology

Genetic engineering antibody technology

Because the hybridoma monoclonal antibody is a heterologous protein, it is easy to produce anti-mouse antibodies when applied to humans. Genetically engineered antibodies use genetic engineering techniques to transform the existing excellent mouse monoclonal antibody genes. Minimize the mouse-derived components in the antibody and retain the specificity of the original antibody to create a new type of antibody.

1. Humanized antibodies

Humanized antibodies mainly refer to murine monoclonal antibodies that have been re-expressed by gene cloning and DNA recombination technology. Most of their amino acid sequences are replaced by human sequences, which basically retains the affinity and specificity of the parental murine monoclonal antibodies and decreases Because of its heterogeneity, it is beneficial to the human body.

1. Human-mouse chimeric antibody

This antibody is an antibody prepared by connecting human IgG C region and mouse IgV region through genetic engineering technology and introducing it into cells for expression.

2. Surface modification of antibodies to humanize the Fv surface.

2. Small molecule antibody

This is a molecular fragment with small molecular weight and antigen binding function, including Fab, Fv, single chain antibody, single region antibody, etc.

Such an antibody has a small molecular weight, can be expressed in prokaryotic cells such as E. coli, and has strong penetration in the human body, which is beneficial to the treatment of diseases.

3. Antibody fusion protein

Fusion of antibody molecule fragments with other proteins can produce fusion proteins with diverse biological functions, such as:

1. Antibody fusion protein containing Fv segment: Fv is linked with certain toxins, enzymes, and cytokine genes. Through the guidance of these antibodies, its biologically active substances can be directed to specific parts of target cells, so-called "biological missiles".

2. Chimeric receptors: ScFv is fused with certain cell membrane protein molecules to form a fusion protein that can be expressed on the cell surface and is called a chimeric receptor. Because its mediated killing effect is not restricted by MHC, it is adoptive It has potential application value in immunotherapy.

3. Fc-containing antibody fusion protein: CD4 molecular extracellular membrane is fused with Fc and expressed by eukaryotic cells. This fusion protein can compete with HIV to block the infection of sensitive cells by HIV; it can also mediate ADCC and CDC, which can pass through the placenta.

4. Bispecific antibodies

Two small molecule antibodies with different bispecificities are linked together to obtain bispecific antibodies.

Bispecific antibodies can bind two antigens at the same time, so they can mediate the binding of the label to the target antigen or localize certain effectors to the target cells. In immunological detection, the operation steps can be simplified and the quality of the test can be improved. The mediated drug killing effect can be used for the treatment of tumors and the like.

5. Antibody library technology

Antibody library technology refers to gene cloning technology that clones a full set of antibody heavy and light chain variable region genes, recombines into a plasmid expression vector, directly expresses functional antibody molecule fragments through E. coli, and finally selects specific variable region genes , Existing combination antibody library technology and bacterial antibody library technology.