IgA

American

Immunology.

immunoglobulin A: a class of antibodies predominant in respiratory and alimentary tract secretions and in saliva and tears, functioning as the body's first line of defense against invading foreign substances especially by neutralizing viral antigens and by preventing the adherence of bacteria to mucous membrane surfaces.

Etymology

Origin of IgA

First recorded in 1960–65

Example Sentences

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IgA

They also suggest a possible link to IgA nephropathy, an autoimmune kidney disease.

From Science Daily ● Dec. 23, 2025

Absence or low levels of mucosal IgA is known to be associated with an increased risk of SARS-CoV-2 breakthrough infections.

From Science Daily ● Jan. 10, 2024

In September 2022, she and her colleagues reported that people who were infected early in the pandemic, before they were vaccinated, had detectable levels of SARS-CoV-2–specific antibodies of a type named IgA in their noses.

From Science Magazine ● Jan. 24, 2023

Gommerman is intrigued by the potential for IgA antibodies in the nose and saliva as well.

From Science Magazine ● Jan. 24, 2023

Secreted IgA is abundant in tears, saliva, breast milk, and in secretions of the gastrointestinal and respiratory tracts.

From Textbooks ● Jun. 9, 2022

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023