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Antiserum (Pl. Antisera)

Definition

Blood serum from an animal (typically a rabbit) that has been immunised against the proteins of another species. It contains antibodies that react specifically with proteins from the immunising species.

Source
Blood serum from an immunised animal, typically rabbit
Contains
Antibodies specific to the immunising species' proteins
Forensic use
Species-of-origin identification via precipitin testing
Plural form
Antisera

Common questions

How does an antiserum panel identify the species a bloodstain came from?+

A stain extract is tested against a panel of antisera each raised against a different species, and a positive precipitin reaction only occurs with the antiserum matching the stain's species of origin, so the pattern of reactions across the panel identifies the source.

Can an antiserum give a false positive against an unrelated species?+

Weak cross-reactivity can occur between closely related species because their serum proteins share some structural similarity, which is why validated antisera are checked for specificity against a range of species before use and results are interpreted alongside the reaction strength.

Related terms

Double Immunodiffusion (Ouchterlony)
A gel diffusion method in which both antigen and antibody diffuse toward each other from separate wells in agar. Precipitin bands form...
Precipitin Arc / Line
The visible band of precipitate in an Ouchterlony plate where diffusing antigen and diffusing antibody meet. Its shape and relationship to adjacent...
Precipitin Test
A serological method in which an antiserum specific to one species' proteins is mixed with an extract of an unknown specimen. Formation...
Ring Precipitin Test
A tube-based precipitin assay in which the antiserum is carefully underloaded beneath the sample; a ring of precipitate at the interface indicates...
Spur Formation
In Ouchterlony, a spur is formed when one arc curves beyond another due to an excess of a cross-reacting but non-identical antigen....

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