Innate Immunity Lecture Notes

Comprehensive vocabulary flashcards covering the characteristics, cells, processes, and clinical assessments associated with innate immunity as described in the lecture.

Innate Immunity

A division of the immune system that is present and active at birth, is not specific, and has no memory.

Adaptive Immunity

A division of the immune system that may be present at birth but is not active until later, is specific, and possesses memory.

Phagocytosis

The process by which one cell engulfs something else, such as an antigen, to destroy it.

Neutrophil

The most numerous white blood cell ($57 - 65\%$), also called a microphage or Polymorphonuclear cell (PMN) due to its multi-shaped nucleus.

Monocyte

The largest white blood cell (WBC) in the blood, referred to as a macrophage when in tissues.

Microglial cells

The name for macrophages when located in the Central Nervous System (CNS).

Kupffer Cell

The name for macrophages when located in the liver.

Mesangial cells

The name for macrophages when located in the kidney.

Cytokines

Biologically active molecules synthesized by cells, such as macrophages, to activate other cells.

Interleukin-6 ($IL-6$)

A macrophage-derived cytokine that stimulates liver cells to secrete C-reactive protein (CRP), which acts as an opsonin.

Interleukin-12 ($IL-12$)

A cytokine that activates natural killer (NK) cells to secrete gamma interferon ($IFNG$ or $IFN-\gamma$).

Diapedesis

The process by which white blood cells, such as neutrophils, exit the blood vessel through the walls and enter the tissues.

Pus

A substance made up of white blood cells (primarily neutrophils) that have died after defending the body from pathogens.

Opsonization

The process of coating a microorganism with substances called opsonins to enhance and facilitate phagocytosis.

Phagosome

A vacuole formed inside a phagocyte after it has engulfed a microorganism.

Phagolysosome

The structure created when a phagosome fuses with a lysosome, allowing digestive enzymes to kill the microorganism.

Chemotaxis

Movement of cells due to chemical signals; it is positive if the movement is toward the activator and negative if away.

Antigen Presenting Cells (APCs)

Cells like macrophages that endocytose antigens, degrade them, and display fragments on their surface to activate the adaptive immune system.

Natural Killer Cells (NK cells)

Cells that function against viral infections and tumors; they use $Fc\gamma R$ receptors to detect Immunoglobulin G ($IgG$).

Perforin

A substance released by NK cells that perforates (creates holes in) the target cell membrane.

ADCC

Antibody dependent cellular cytotoxicity; the mechanism by which NK cells kill target cells mediated by $IgG$ antibodies.

Eosinophil

Inflammatory cells activated in response to parasitic infections; they possess $FC\epsilon R$ receptors to detect $IgE$.

Major Basic Protein (MBP)

A substance released by eosinophils to kill parasites.

Histamine

A substance released by basophils and mast cells when they degranulate, often causing allergic reactions.

MMT

$3(4,4 dimethyl thiazoyl-2-yl) 2,5-diphenyltetrazolium bromide$; a dye used to determine if bacteria are still alive during testing.

Boyden chamber assay

An assessment used to determine if phagocytes are reacting and migrating toward a chemotaxin.

Nitroblue Tetrazolium

A clear yellow dye that turns blue when NADPH oxidase is activated; failure to change color is seen in Chronic Granulomatous Disease (CGD).