Antibody Production

More Information

Antibodies bind specifically to target molecules. Because of the binding specificity, antibodies have been widely used in life science research, and more recently in the areas of medical and diagnostic applications. Antibodies are produced by taking advantage of biological defense mechanisms of living organisms and are generated in animals.

Antibodies are produced by B cells, which are immune cells, when foreign substances such as pathogens enter the body. Antibodies bind specifically to foreign substances that act as antigens and contribute to the response to eliminate them.

Antibodies are produced by repeated injections of an antigen as an immunogen into animals such as mice, hamsters, rabbits, donkeys, and goats. Some antigens, however, may not easily induce antibody production, and an appropriate method of immunization should be selected depending on the antigen.

Promoting Immune Response with Adjuvants

For immunogens with weak antigenicity, use of adjuvants that increase the ability of macrophages to capture antigens is effective. Mixing the adjuvant with the immunogen enhances antibody response and increases the efficiency of antibody production. The mechanisms are nonspecific stimulation of immune response and facilitated precipitation and sequestration of the injected materials.

There are two types of adjuvants, called complete and incomplete Freund's adjuvants. Complete Freund's adjuvant is used for the initial injection, and incomplete Freund's adjuvant is used for subsequent injections. While Freund's adjuvant is highly effective, it contains mycobacteria (dead bacteria) and may be toxic to the host animals.

Aluminum hydroxide solution is also widely used as an alternative to Freund's adjuvant in such situations. Aluminum hydroxide is not as effective as complete Freund's adjuvant, but it can reduce the toxicity.

What Are Carrier Proteins?

Carrier proteins are used when small molecules, such as drugs, are used as antigens to produce antibodies. Carrier proteins are used for antibody production with haptens, which do not elicit an immune response due to their insufficient size or simple structure. When combined with a carrier protein, the size and complexity of the immunogen increase, and an immune response is generated. Bovine serum albumin is widely used as a carrier protein.