humoral immunity

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hu·mor·al im·mu·ni·ty

immunity associated with circulating antibodies, in contradistinction to cellular immunity. The inherent range of activity of antibody specificities is wide but proliferation of antigen-specific B cells occurs rapidly during infections leading to rapid increases in antibody titers with enhanced affinity for the inciting agent, and a more effective and directed response.
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humoral immunity

n.
Immunity involving the transformation of B-lymphocytes into plasma cells that produce and secrete antibodies to a specific antigen.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.

hu·mor·al im·mu·ni·ty

(hyū'mŏr-ăl i-myū'ni-tē)
Immunity associated with circulating antibodies, in contradistinction to cellular immunity.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012
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HUMORAL IMMUNITY

humoral immunity

The protective activities of antibodies against infection or reinfection by common organisms, e.g., streptococci and staphylococci. B lymphocytes with receptors to a specific antigen react when they encounter that antigen by producing plasma cells (which produce antigen-specific antibodies) and memory cells (which enable the body to produce these antibodies quickly in the event that the same antigen appears later). B-cell differentiation also is stimulated by interleukin-2 (IL-2) secreted by CD4+ T cells and foreign antigens processed by macrophages.

Antibodies produced by plasma B cells, found mainly in the blood, spleen, and lymph nodes, neutralize or destroy antigens in several ways. They kill organisms by activating the complement system; neutralize viruses and toxins released by bacteria; coat the antigen (opsonization) or form an antigen-antibody complex to stimulate phagocytosis; promote antigen clumping (agglutination); and prevent the antigen from adhering to host cells.

Synonym: B-cell–mediated immunity See: illustration; cell-mediated immunity; immunoglobulin
See also: immunity
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