Alterations in Immune Function Flashcards

Vocabulary flashcards covering types of hypersensitivity, chemical mediators, pharmacology, and autoimmunity based on lecture notes.

Hypersensitivity

An inappropriately triggered or excessive normal immune response to a harmless environmental molecule that produces undesirable effects on the body upon re-exposure.

Antigens

Foreign protein or carbohydrate molecules recognized by the immune system that trigger an immune response.

B-lymphocytes

Lymphocytes that produce specific antibodies or immunoglobulins that bind to antigens to neutralize or destroy them.

Cytotoxic T-cells (CD8)

T-lymphocytes possessing receptors that recognize specific antigens and exert toxic effects directly on specific target cells.

Helper T-cells (CD4)

T-lymphocytes that assist other immune cells, including stimulating B-cells to mature into antibody-producing plasma cells.

Type I Hypersensitivity

An immediate IgE-mediated reaction occurring within 15 to 20 minutes after initial sensitization, involving mast cell degranulation and histamine release.

Histamine

An intracellular chemical mediator dumped by mast cells during Type I hypersensitivity that triggers vasodilation, increased vascular permeability, bronchial constriction, and pruritus.

Type II Hypersensitivity

A cytotoxic or antibody-mediated reaction where IgG or IgM antibodies bind to cell surface antigens, resulting in direct cell lysis or phagocytosis.

Erythroblastosis Fetalis

A Type II hypersensitivity reaction in which maternal antibodies from an Rh-negative mother cross the placenta and attack red blood cells of an Rh-positive fetus.

Membrane Attack Complex

A cylindrical complex composed of C5b, C6, C7, C8, and C9 complement proteins that inserts into cell membranes, causing cell swelling and bursting.

Type III Hypersensitivity

An immune complex-mediated reaction where antigen-antibody (IgG and IgM) complexes deposit into blood vessel walls or tissues, activating complement and recruiting tissue-damaging neutrophils.

Type IV Hypersensitivity

A delayed, T-cell-mediated hypersensitivity reaction that does not involve antibodies and is mediated by CD8 cytotoxic T-cells, helper T-cells, haptens, and macrophages.

Haptens

Small, incomplete antigens that penetrate the skin and bind to body proteins to form complete antigens recognized by antigen-presenting cells.

Diphenhydramine

A first-generation H1 receptor antagonist administered PO, IM, or IV that produces sedation and treats allergic manifestations such as motion sickness, itching, and edema.

Epinephrine

An adrenergic agonist and sympathomimetic agent with both $\alpha$ and $\beta$ receptor actions used as the primary treatment for life-threatening anaphylaxis.

Central Tolerance

An immunological tolerance mechanism in which self-reactive T and B lymphocytes that recognize self-proteins are eliminated inside central lymphoid tissues and organs.

Peripheral Tolerance (Anergy)

An immunological mechanism where self-reactive lymphocytes that escape central tolerance are rendered functionally inactivated in peripheral tissues.

Antigenic Mimicry

A process in which bacterial or viral antigens structurally resemble self-antigens, causing the immune system to attack host tissues following an infection.