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Immune System

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Immune System

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Immune System

Basics

The immune system’s defenses are orchestrated by a complex array of circulating cells known as lymphocytes and monocytes, collectively referred to as white blood cells. The term “cyte” denotes cells. There are two primary classes of lymphocytes: T cells and B cells. Both originate in the bone marrow, but T cells migrate to mature in the thymus (hence the “T”), while B cells mature in the bone marrow.

T Cells

  • Function: T cells are responsible for cell-mediated immunity.
  • Process:
    • When an infectious agent invades the body, it is recognized by a type of monocyte called a macrophage.
    • The macrophage presents the foreign particle to a T helper cell, triggering an alarm.
    • T cells proliferate in response, leading to the activation and proliferation of cytotoxic killer cells, which attack and destroy the infectious agent.
  • Impact of AIDS: The T-cell component is notably affected by the AIDS virus.

B Cells

  • Function: B cells are involved in antibody-mediated immunity.
  • Process:
    • After the macrophage–T helper cell collaboration, T helper cells stimulate B-cell proliferation.
    • B cells differentiate and generate antibodies, large proteins that recognize and bind to specific features of the invading infectious agent, typically a distinctive surface protein.
    • This specificity is crucial, as the antibody’s shape conforms perfectly to the invader’s feature, akin to a lock and key fit.
    • Antibodies immobilize the infectious agent and target it for destruction.

Allergies

  • Description: An allergy occurs when the immune system mistakenly identifies a harmless substance, such as peanuts, shellfish, or pollen, as dangerous and mounts a defense.

Immune Response

  • Generalized Response: Occurs at the initial site of pathogen entry, such as the skin or mucosal tissues like the mouth or nose.
  • Saliva: Contains antibodies that generically attack microbes, coating mucosal surfaces like antiseptic paint.

Long-term Immunity

  • Repeated Exposure: Once a specific defense is established, repeated exposure to the same pathogen enhances targeted defenses.

see also

Tags: science medicine
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Source

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Created: 01-09-22 11:32