Quellung reaction

Quellung reaction

The Quellung reaction is a biochemical reaction in which antibodies bind to the capsule of "Streptococcus pneumoniae" and thus allow it to be visualized under a microscope. If the reaction is positive, the capsule becomes opaque and appears to enlarge.

Quellung is the German word for "swelling" and describes the microscopic appearance of pneumococcal or other bacterial capsules after their polysaccharide antigen has combined with a specific antibody. The antibody usually comes from a bit of serum taken from an immunized laboratory animal. As a result of this combination, and precipitation of the large, complex molecule formed, the capsule appears to swell, because of increased surface tension, and its outlines become clearly demarcated.


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  • quellung reaction — noun the swelling of the capsule surrounding a microorganism after reaction with an antibody; the basis of certain tests for identifying microorganisms pneumococcus quellung • Syn: ↑quellung • Hypernyms: ↑organic process, ↑biological process …   Useful english dictionary

  • quellung reaction — a reaction in which antibodies against the bacterium Streptococcus pneumoniae combine with the bacterial capsule, which becomes swollen and visible to light microscopy. * * * [Ger. “swelling”] Neufeld r …   Medical dictionary

  • quellung reaction — a reaction in which antibodies against the bacterium Streptococcus pneumoniae combine with the bacterial capsule, which becomes swollen and visible to light microscopy …   The new mediacal dictionary

  • Quellung reaction — The increase in visibility or the swelling of the capsule of a microorganism in the presence of antibodies against capsular antigens …   Dictionary of microbiology

  • Quellung reaction — Swelling of the capsule surrounding a bacterium as a result of interaction with anticapsular antibody; consequently the capsule becomes more refractile and conspicuous …   Dictionary of molecular biology

  • quellung — noun the swelling of the capsule surrounding a microorganism after reaction with an antibody; the basis of certain tests for identifying microorganisms pneumococcus quellung • Syn: ↑quellung reaction • Hypernyms: ↑organic process, ↑biological… …   Useful english dictionary

  • Реакция Набухания (Quellung Reaction) — реакция, в ходе которой антитела к бактериям вида Streptococcus pneumoniae соединяются с антигенами капсул бактерий, которые набухают и становятся видимыми в обычный световой микроскоп. Источник: Медицинский словарь …   Медицинские термины

  • reaction — 1. The response of a muscle or other living tissue or organism to a stimulus. 2. The color change effected in litmus and certain other organic pigments by contact with substances such as acids or alkalies; also the property that such substances… …   Medical dictionary

  • quellung test — Neufeld reaction; see under reaction …   Medical dictionary

  • quellung — quel·lung kwel əŋ, kvel u̇ŋ n, often cap swelling of the capsule of a microorganism after reaction with antibody …   Medical dictionary

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