antigenic shift


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Related to antigenic shift: Antigenic drift

shift

 [shift]
a change or deviation.
antigenic shift a sudden, major change in the antigenicity of a virus, seen especially in influenza viruses, resulting from the recombination of the genomes of two different strains; it is associated with pandemics because hosts do not have immunity to the new strain. See also antigenic drift.
chloride shift the exchange of chloride and carbonate between the plasma and the erythrocytes that takes place when the blood gives up oxygen and receives carbon dioxide. It serves to maintain ionic equilibrium between the cell and surrounding fluid.
mediastinal shift a shifting to one side of the tissues and organs of the mediastinum; see also mediastinal shift.
shift to the left
1. a change in the blood picture, with a preponderance of young neutrophils.
2. an increased oxygen affinity of hemoglobin.
shift to the right
1. a preponderance of older neutrophils in the blood picture.
2. a decreased oxygen affinity of hemoglobin.
weight shift
1. the frequent movement of a paralyzed or partially paralyzed patient to redistribute the patient's weight and prevent impairment of circulation, which leads to pressure sores. One variation is the wheelchair pressure release.
2. relocation of a patient's center of mass in order to allow movement; see also gait.

an·ti·gen·ic shift

mutation, that is, sudden change in molecular structure of RNA/DNA in microorganisms, especially viruses, which produces new strains; hosts previously exposed to other strains have little or no acquired immunity to the new strain; antigenic shift is believed to be the explanation for the occurrence of new strains of influenza virus, which occur by recombination or genetic reassortment of two different viral strains in a given host, and is associated with large-scale epidemics.

antigenic shift

a sudden, major change in the antigenicity of a virus, seen especially in influenza viruses, resulting from the recombination of the genomes of two different strains; it is associated with pandemics because hosts do not have immunity to the new strain. Compare antigenic drift.

an·ti·gen·ic shift

(an'ti-jen'ik shift)
Mutation, i.e., sudden change in molecular structure of RNA/DNA in microorganisms, especially viruses, which produces new strains of the microorganism; hosts previously exposed to other strains have little or no acquired immunity to the new strain.

antigenic shift

major changes in surface ANTIGENS caused by the reassortment of GENES between different INFLUENZA VIRUSES. This may involve the mixing of genes from influenza viruses of humans and of animals, such as pigs or ducks. Typically this phenomenon results in a sudden change, approximately every 10 to 15 years, in the predominant type of influenza virus, causing PANDEMICS in humans.

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.

shift

a change or deviation.

antigenic shift
see antigenic shift.
chloride shift
see chloride shift.
shift to the left
an alteration in the distribution of leukocytes in the peripheral blood in which there is an increase in the numbers of immature neutrophils, primarily band forms but metamyelocytes or more immature cells may also be present; usually in response to an infection.
Enlarge picture
Canine blood smear showing a shift to the left with a segmented neutrophil (left) with toxic vacuolation and a metamyelocyte (right) with two Döhle bodies. By permission from Willard MD, Tvedten H, Small Animal Clinical Diagnosis by Laboratory Methods, Saunders, 2003
shift red cell
shift to the right
an alteration in the distribution of leukocytes in the peripheral blood in which there is an increased number of mature neutrophils but no immature cells are present.
References in periodicals archive ?
After an interpandemic interval >35 years, any antigenic shift may again seriously affect young adults, including many pregnant women.
Issues addressed included the growing body of evidence linking the origin of antigenic shift to animal reservoirs of influenza viruses (24), the questionable validity of predictable patterns of pandemic periodicity, and the appropriate classification of the 1947 strain (25).
No precedent existed for defining a pandemic strain or distinguishing antigenic shift (a complete change) from antigenic drift (point mutations resulting in accumulated amino acid changes).
Surveillance of circulating viruses is increasing and flu vaccination has entered the mainstream, but epidemics are still frequent and strains arising from antigenic shift keep the next flu pandemic just around the corner.
Antigenic shifts are associated with the epidemics and pandemics of influenza A, whereas antigenic drifts are responsible for more localized outbreaks of varying extent.
Due to the segmented pattern of the influenza virus gene and the high rates of reassorment on its genome, the emergence of pandemic strains usually has been caused by animal- and human-type reassorment and the resultant antigenic shifts.
Major variations known as antigenic shifts are the cause of serious outbreaks and pandemics as the 1918, 1957, and 1968 worldwide outbreaks (4).
DNA polymorphism analysis of prn and ptxS1 has previously been used as a typing method for detecting antigenic shifts (2,3,8).
Our results suggest that ptxS1 is not a useful marker in outbreaks to detect antigenic shifts.
As described in our prior publication (4), vaccinia is a DNA virus with limited antigenic variability (8), and antigenic shifts are unlikely.
Therefore, a greater proportion of infected vaccinated persons may have had clinical symptoms because of antigenic shifts, which probably led to greater transmission of bacteria and thus a greater degree of infection in the population.