iQ Biosciences

In the final part of our series on bi-specific antibodies, we’ll discuss some of the assays that are used to test the specificity, functionality, and safety of bi-specific antibodies. How are bi-specific antibodies tested for antigen specificity? As described in our previous blogs, bi-specific antibodies have the capability to recognize two different antigens due to the presence of two different antigen recognition domains.  To ensure that each arm has specificity for the correct antigen, binding assays are performed with a cell line that expresses the antigen recognized by one arm of the bi-specific antibody.  Typically, flow cytometry is used as [...]

How were bi-specific antibodies initially created? Each individual bivalent, monospecific antibody is composed of two identical heavy chains and two identical light chains, in which a single heavy chain combines with a light chain to create an individual target antigen recognition site.  Since there are two antigen binding sites per antibody, two heavy-light chain pairs combine and form a bivalent, monospecific antibody.  When producing these antibodies, only one heavy chain and its corresponding light chain is expressed by the cells because there is only one specific target antigen for the antibody. In contrast, bi-specific antibodies are created by expressing two [...]

What is a bi-specific antibody? Bi-specific antibodies are a class of engineered antibodies developed for various oncology indications and autoimmune diseases.  Typically, the antigen recognition domains on the tips of the F(ab)2 fragment of a standard antibody are identical and bind the same antigen.  In contrast, bi-specific antibodies have different antigen recognition domains on each of those tips and each tip will thus bind a different antigen. With advances in genetic and protein engineering and recombinant protein expression, different types of bi-specific antibodies can be produced.  While there are a variety of bi-specific antibodies that are found in at least [...]