Monospecific antibodies are antibodies whose specificity to

antigen In immunology, an antigen (Ag) is a molecule or molecular structure or any foreign particulate matter or a pollen grain that can bind to a specific antibody or T-cell receptor. The presence of antigens in the body may trigger an immune respons ...

s is singular (''mono-'' + ''specific'') in any of several ways: antibodies that all have affinity for the same

; antibodies that are specific to one antigen or one

epitope An epitope, also known as antigenic determinant, is the part of an antigen that is recognized by the immune system, specifically by antibodies, B cells, or T cells. The epitope is the specific piece of the antigen to which an antibody binds. The p ...

; or antibodies specific to one type of

cell Cell most often refers to: * Cell (biology), the functional basic unit of life Cell may also refer to: Locations * Monastic cell, a small room, hut, or cave in which a religious recluse lives, alternatively the small precursor of a monastery ...

or tissue. Monoclonal antibodies are monospecific, but monospecific antibodies may also be produced by other means than producing them from a common germ cell. Regarding antibodies, ''monospecific'' and ''monovalent'' overlap in meaning; both can indicate specificity to one antigen, one

, or one cell type (including one

microorganism A microorganism, or microbe,, ''mikros'', "small") and ''organism'' from the el, ὀργανισμός, ''organismós'', "organism"). It is usually written as a single word but is sometimes hyphenated (''micro-organism''), especially in olde ...

species). However, antibodies that are monospecific to a certain tissue, or all monospecific to the same tissue because clones, can be polyvalent in their epitope binding.

Production

Hybridoma cell

Monoclonal antibodies are typically made by fusing the spleen cells from a mouse that has been immunized with the desired antigen with myeloma cells. However, recent advances have allowed the use of rabbit B-cells.

PrEST

Another way of producing monospecific antibodies are by PrESTs. A PrEST (protein epitope signature tag) is a type of recombinantly produced human protein fragment. They are inserted into an animal, e.g. rabbit, which produces antibodies against the fragment. These antibodies are monospecific against the human protein.

Cautions

Recent research has led to the discovery that unstable hinged monospecific antibodies may engage in a process leading to a decrease in their apparent avidity/affinity. This process, termed Fab arm exchange, has led to theories about the dissemination of viral infections in patients given monospecific IgG4 therapeutic antibodies. Evidence is suggestive that this process is linked to the dissemination of PML in patients given Tysabri for MS. Following dosing unpredictability still reigns and mutations in the hinge of the antibody which may prevent Fab-arm exchange in-vivo should be considered when designing therapeutic antibodies.

References

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Production

Hybridoma cell

PrEST

Cautions

References

See also