antigenic drift

antigenic drift

Etymology: Gk, anti, against, genein, to produce; AS, drifan, drift

a gradual relatively minor change in the antigenicity of a virus, periodically producing a mutant antigen requiring new antibodies and vaccines to combat its effects. Compare antigenic shift.

---

antigenic drift (an´tējen´ik),

n the ability of viruses to alter their genetic makeup, thereby creating mutant antigens and bypassing the antibody barrier of the host.

---

antigenic

having the properties of an antigen.

---

antigenic competition

the immune response to an antigen may be reduced if an unrelated antigen is administered simultaneously or shortly before. These may be between different molecules (intermolecular) or different determinants on the same molecule (intramolecular).

antigenic drift

point mutations in genes resulting in antigenic change. See also orthomyxoviridae.

antigenic mimicry

similarities between sequences found in microbial proteins and host proteins which may result in cross-reacting immune responses and autoimmune disease.

antigenic shift

genetic reassortment between two subtypes of a viral species resulting in a new subtype with completely different antigenicity. See also orthomyxoviridae.

---

drift

chance variation; in genetics, the random changes in gene frequencies in a population.

---

antigenic drift

see antigenic drift.

drift lambing

a strategy in which ewes which have lambed are periodically removed from a flock of lambing ewes by moving the unlambed ewes on to the next paddock or field.