immunological tolerance

immunological tolerance

n.

Acquired specific failure of the immunological mechanism to respond to a given antigen, induced by exposure to the antigen.

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tolerance

the ability to endure without effect or injury.

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drug tolerance

1. decreased susceptibility to the effects of a drug due to its continued administration.

2. the maximum permissible level of a drug in or on animal feed or food at any particular time relative to slaughter.

high-dose tolerance

in immunology, that induced by the intravenous administration of high doses of aqueous proteins.

immunological tolerance

specific nonreactivity of the immune system to a particular antigen, which is capable under other conditions of inducing an immune response. There is, under normal circumstances, tolerance to self-antigens; identical (monozygotic) twins and dizygotic cattle or sheep twins where there has been placental fusion and exchange of bone marrow stem cells are also tolerant of each other's tissues. Allophenic mice, that is mice produced by fusion of blastocysts from different mice are also tolerant of both 'parents'. The administration of antigens either at high or low dose and infection with certain viruses during critical early stages of immunological development may also induce tolerance.

tolerance level

the concentration of a drug or chemical permitted by law to be present in human food.

tolerance limits

the numerical limits within which a previously identified proportion of values of a variable, or observations in a population, can be expected to occur.

low-dose tolerance

that induced by repeated administration of low doses of the antigen.

oral tolerance

that induced by oral administration of the antigen.

self-tolerance

the non-reactivity of the immune system to self-antigens.

tolerance test

see tolerance test.

zero tolerance

when no detectable amount of a chemical substance is permitted in human food.