Natural Immunity, Phagocytosis, and Inflammation

Comprehensive vocabulary flashcards generated from lecture notes covering natural immunity cellular components, PRRs/PAMPs, acute-phase reactants, phagocytic mechanisms, and inflammation stages.

Neutrophil

The earliest and most numerous granulocyte cell type to respond to most infections, serving as the predominant white blood cell in acute inflammation.

Eosinophil

A granulocyte that neutralizes basophil and mast cell products, suppresses inflammatory reactions, and kills parasites using constituents like Major Basic Protein (MBP).

Basophil

A granulocyte containing histamine, heparin, and eosinophil chemotactic factor that participates in anaphylactic or immediate hypersensitivity reactions.

Histamine

A potent chemical mediator contained within basophil granules that drives type 1 or anaphylaxis hypersensitivity reactions.

Major Basic Protein (MBP)

An eosinophil granule component that is highly toxic to parasites but also causes non-selective tissue damage and inflammation.

Monocyte

A mononuclear leukocyte that participates in phagocytosis and antigen presentation, secretes cytokines, and migrates into tissues to become a macrophage.

Mast Cell

A tissue cell resembling a basophil that participates in hypersensitivity reactions by binding IgE antibodies.

Macrophage

A tissue cell that performs phagocytosis, antigen presentation, and cell mediator secretion to eliminate bacteria, tumor cells, and intracellular parasites; it is the predominant cell in chronic inflammation.

Dendritic Cell

The most potent phagocytic cell in tissues and the most effective antigen-presenting cell (APC).

Langerhans Cell

The specialized designation for dendritic cells found residing in the skin and mucous membranes.

Kupffer Cell

The specific anatomical term for macrophages located in the liver.

Microglial Cell

The specific anatomical term for macrophages located in the central nervous system (CNS) or brain.

Pathogen-Associated Molecular Patterns (PAMPs)

Molecular structures associated with groups of pathogens that are recognized by cells of the innate immune system.

Pattern Recognition Receptors (PRRs)

Innate immune system receptors that bind specifically to pathogen-associated molecular patterns (PAMPs).

Toll-Like Receptors (TLRs)

A set of transmembrane PRRs, originally discovered in Drosophila, highest in concentration on monocytes/macrophages and neutrophils, that recognize various microbial PAMPs.

TLR4

A cell surface Toll-Like Receptor that recognizes lipopolysaccharide, fusion proteins, and mannan from Gram-negative bacteria, respiratory syncytial virus, and fungi.

Acute-Phase Reactants (APRs)

Normal serum constituents produced primarily by hepatocytes that increase rapidly by at least 25 percent within 12 to 24 hours in response to tissue injury, infection, or trauma.

Interleukin 6 (IL-6)

The major cytokine responsible for inducing hepatocytes to produce acute-phase reactants (APRs).

Opsonization

The enhancement of phagocytosis achieved by coating foreign particles with serum proteins such as antibodies, complement C3b, or CRP.

C-Reactive Protein (CRP)

The best indicator of acute inflammation and a trace serum constituent that binds phosphocholine on microbial membranes to promote opsonization, complement activation, and agglutination.

Hs-CRP

High-sensitivity C-reactive protein test value used as a significant risk factor marker for myocardial infarction and ischemic stroke.

Serum Amyloid A (SAA)

An acute-phase reactant associated with HDL cholesterol that functions in removing cholesterol-filled macrophages at tissue injury sites and activating monocyte cytokine production.

Alpha 1 Antitrypsin

A general plasma inhibitor of leukocyte proteases (especially elastase) whose deficiency leads to premature emphysema and juvenile cirrhosis.

Ceruloplasmin

The principal copper-transporting protein in human plasma and an APR with enzymatic ferroxidase activity ($Fe^{2+}$ to $Fe^{3+}$) that is depleted in Wilson's disease.

Haptoglobin

An acute-phase reactant that binds irreversibly to free hemoglobin to protect against oxidative damage; its levels are decreased in intravascular hemolysis.

Chemotaxis

The process by which cells move in a directional manner toward an inflammatory or infectious site under stimulation by chemical substances called chemotaxins.

Respiratory Burst

An oxygen-dependent microbial killing process in phagocytes that reduces oxygen to generate reactive oxygen species (ROS) like superoxide anion, hydrogen peroxide, and hypochlorite ions.

Hydrogen Peroxide ($H_2O_2$)

The most potent and lethal bactericidal product formed during the respiratory burst pathway.

NADPH Oxidase

The enzyme central to microbial killing during respiratory burst, whose deficiency results in Chronic Granulomatous Disease (CGD).

Chronic Granulomatous Disease (CGD)

An inherited disorder marked by NADPH oxidase deficiency leading to impaired respiratory burst, impaired bacterial digestion, and recurring severe bacterial infections.

Defensins

Lytic enzymes released from lysosomal granules that cleave bacterial cell walls without requiring oxygen.

Lactoferrin

An iron-binding protein found in secretory fluids and PMN secondary granules that protects against bacterial growth by depriving microbes of essential iron.

Chemokines

Cytokines that create chemical gradients to direct the movement of leukocytes specifically toward sites of infection or inflammation.

Diapedesis

The process, also known as transmigration, by which leukocytes squeeze between or across endothelial cells of blood vessel walls into surrounding tissue.

Rubor

The first cardinal sign of inflammation representing redness, caused by small blood vessel dilation and localized hyperemia.

Calor

The cardinal sign of inflammation representing heat, caused by increased blood flow bringing core body temperature to the injured area.

Tumor

The cardinal sign of inflammation representing swelling (edema), caused by fluid accumulation outside blood vessels due to increased vascular permeability.

Dolor

The cardinal sign of inflammation representing pain, caused by tissue distortion from edema and chemical mediators such as bradykinin, serotonin, and prostaglandins.

Functio Laesa

The fifth cardinal sign of inflammation representing loss or diminished function, introduced by Rudolf Virchow.

Transthyretin

A negative acute-phase reactant (also known as prealbumin) named for its function in transporting thyroxine and retinol (vitamin A).