Glossary of Terms


A substance or compound often used during antibody production to increase the immune response.


The term affinity refers to the attractive force between substances or particles that cause them to enter into and remain in chemical combination. It is often used to describe the binding or interaction of antibody and antigen.

Affinity Purification

A technique used in antibody purification to yield highly specific antibodies, it involves columns containing the antigen to which it was raised.


A protein produced by our body in response to the presence of an antigen or hapten. There are 5 classes of antibodies (IgG, IgM, IgE, IgA, IgD). The antibody binds to and neutralises the antigen.


An antigen is any foreign substance e.g. protein, bacteria or virus that stimulates the immune response and the production of antibody's when introduced to the body.


Bovine Serum Albumin

Capture Antibody

Capture antibodies are used to coat each well of a micro titre plate for use in sandwich ELISAs. The antibody is specific to the antigen of interest and will therefore bind "capture" it when the solution is added to the wells.

Carrier Free

Carrier proteins e.g. BSA are sometimes added to recombinant proteins for stability. All Randox recombinant proteins are supplied in a carrier free format.


A substance capable of converting into a pigment or dye in the presence of enzyme tagged antibodies.


The term conjugate refers to an antibody that is chemically bound to either a fluorochrome or chromogen allowing visual detection of the antibody.

Cross Reactivity

Cross reactivity refers to the unspecific binding of an antibody to similar epitopes on an antigen or protein.


A small region present on the surface of antigens where an antibody binds during the immune response.


A molecular label that is conjugated to antibody and emits fluorescent light allowing antibody detection.


A small molecule that induces the immune response and the production of antibodies only when bound to a larger protein or antigenic molecule.


Horseradish peroxidase is an enzyme with 4 lysine residues allowing conjugation to a labelled molecule. HRP is often used in conjugates to determine the presence of a molecular target e.g. an antibody conjugated to HRP can be used to detect a small amount of a particular protein in a western blot.


In 1975 Kohler and Milstein developed a technology to fuse immortal heteromyleoma cells with lymphocytes, using poly ethylglycol (PEG) to break down cell membranes and allow mixing of the genetic material from both cells. The resulting cell type is called a hybridoma which takes on the characteristics of both cell types creating an immortal cell with the ability to produce antibodies. As the new cell line hybridoma is a product of the fusion of one heteromyeloma cell with one B-cell, the culture only ever produces one specific monoclonal antibody.


Any substance capable of inducing an immune response when introduced to the body can be described as an immunogen.


The immunoglobulins are a class of proteins that function as antibodies. There are 5 subclasses; IgG, IgM, IgE, IgA and IgD.


A short sequence of amino acids.

Primary Antibody

Primary antibodies directly bind to the antigen of interest.


A protein is a chain of amino acids encoded by DNA and folded to produce a three-dimensional structure.

Recombinant Protein

A protein derived from recombinant DNA. Recombinant proteins are expressed in various living systems e.g. yeast, mammalian cells and bacteria. Recombinant DNA is inserted into a plasmid and then transformed into one of these systems, allowing the expression of recombinant proteins, such as antibodies, antigens, hormones and enzymes.

Secondary antibody

A conjugated or labelled antibody that binds to the antigen bound primary antibody


How specific a particular antibody is binding to a precise antigen or epitope


The concentration of a solution as determined by titration