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opsonin Syllabification: op·so·nin
Pronunciation: /ˈäpsənən/

Definition of opsonin in English:


An antibody or other substance that binds to foreign microorganisms or cells, making them more susceptible to phagocytosis.
Example sentences
  • By some unknown process, Acupuncture raises levels of triglycerides, specific hormones, prostaglandins, white blood counts, gamma globulins, opsonins, and overall anti-body levels.
  • In all infants, the spleen provides important protection against invading bacteria; it is also a source of opsonins and fixed-tissue macrophages, as well as antibody production.
  • A mixture of opsonins adhere to the bacterium and facilitate ingestion by alveolar macrophages.


Pronunciation: /äpˈsänik/
Example sentences
  • How did opsonic antibodies enhance alveolar macrophage effectiveness?
  • One pool of GAS surface proteins induced antibodies that were both opsonic and potentially protective.
  • Moreover, Lancefield's studies in 1959 showed that type-specific opsonic antibodies can persist for 10-20 years after a GAS infection in humans.


Early 20th century: from Latin opsonare 'buy provisions' (from Greek opsōnein) + -in1.

Definition of opsonin in:
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