What does antiserum mean?
Antiserum is blood serum that contains antibodies directed against a particular pathogen or toxin. Because these antibodies are harvested from immunized animals or recovered human donors rather than produced by the recipient's own immune system, antiserum provides what physicians call passive immunity — immediate but temporary protection. It has long played a critical role in treating diseases such as tetanus, diphtheria, and rabies, where rapid neutralization of a toxin or virus can be lifesaving, and specific forms such as antivenom counter snake and scorpion envenomation. Antisera are also valuable diagnostic reagents in laboratories, where they identify unknown bacteria and viruses by binding to them in characteristic ways. The term belongs chiefly to medical and scientific discourse; in plural form it appears as 'antisera'. Historically momentous, antiserum therapy earned Emil von Behring the first Nobel Prize in Physiology or Medicine in 1901 and remains a foundational concept in immunology.
nounA blood serum containing antibodies against a specific pathogen or toxin, used to confer passive immunity or to diagnose infection.
- Blood serum containing specific antibodies, administered to provide passive immunity against a disease or toxin.
- Serum used in laboratory diagnostics to detect the presence of pathogens or antigens.
"The patient was given tetanus antiserum immediately after the deep puncture wound."
"Doctors administered rabies antiserum around the wound site as part of post-exposure treatment."
"The lab used a reference antiserum to confirm the identity of the bacterial isolate."
The plural 'antisera' is standard in scientific and medical writing when referring to multiple antiserum preparations.
"The panel tested several antisera against the new viral strain."
Emil von Behring won the very first Nobel Prize in Physiology or Medicine in 1901 for developing diphtheria antiserum — a therapy that saved thousands of children's lives.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of antiserum
The word antiserum combines the Greek-derived prefix 'anti-', meaning 'against', with 'serum', from Latin serum, meaning 'whey' — the watery fluid that separates from curdled milk, later applied to the clear fluid portion of blood. The compound arose in late nineteenth-century medical literature as immunologists began using antibody-rich sera therapeutically. Its cognates include other 'anti-' compounds of the same era, such as antibody and antigen, which together formed the vocabulary of the new science of immunology.
Related word forms
How antiserum is actually used
Antiserum is a technical term used mainly in medicine, immunology, and veterinary contexts; it is rarely encountered in casual conversation. In scientific writing it often appears in the plural form 'antisera' when referring to multiple preparations.
Easily confused with antiserum
An antibody is a single immune protein, whereas antiserum is the whole blood serum containing a mixture of such antibodies.
A vaccine stimulates the body to produce its own antibodies, while antiserum supplies ready-made antibodies directly.
Antivenom is a specific type of antiserum raised against snake or other venoms, not a separate general category.