Immune System - Honors Biomedicine

Adaptive Immunity

Delayed (days to weeks). Specific - able to differentiate between self and non-self by way of surface antigens. Memory (develops after exposure to the specific pathogen). T-cells, B-cells, antibodies.

Antigen

Surface proteins on cells.

Antimicrobial Proteins

Proteins that inhibit harmful microbes by inhibiting growth, destruction of cells, promoting growth of comensal (good or friendly) bacteria.

Basophil

Granulocyte - large granules that stain dark blue. Release histamine (vasodilation-veins enlarge to allow increased blood flow and heparin prevents blood clots). Assist eosinophils with parasites and allergic response.

Chemical Barriers

Physical and chemical responses and barriers that prevent pathogens from entering the body. Ex. Skin, stomach acid, mucus, mucous membrane, pH.

Chemotaxis

Chemicals that stimulate movement. Ex. Cytokines, complement, macrophages.

Complement System

Proteins that enhance the body’s ability to fight infections. Removes dead/damaged cells and induces inflammation.

Cytokine

Small proteins produced by immune cells to act as messengers to regulate IR. There main functions are pro-inflammatory, anti-inflammatory, and interferons.

Dendritic Cell

Phagocytes. Concentrated in areas of skin, nose, lungs, and stomach. Antigen presenting cell to T-cell. Considered to be a link between innate and adaptive.

Defensins

Found on skin, neutrophils, and macrophages. Part of Anti Microbial Proteins.

Eosinophil

Phagocytic and red. Identify and destroy parasites and cancer cells. In areas where parasites are less of a health problem they are indicators of asthma and allergy symptoms.

Heparin

Prevents blood clots.

Histamine

They help enlarge veins and increase blood flow, and they are released by white blood cells.

Inflammation

Response that includes redness, pain, warmth, and swelling. Regulated by mast cells and cytokines.

Innate Immunity

The pathogen passed the barriers. Immediate response. Non-specific - doesn’t differentiate from self and non-self. Non-specific WBCs. Non-specific chemical signaling. No memory.

Interferons (IFNs)

Released by macrophages. Signal viral infection and call other WBC to assist. Interferes with viral replication. A function of cytokines.

Interleukins (ILs)

Released by macrophages and call other WBC to assist. Involved with pro-inflammatory and anti-inflammatory functions of cytokines.

Lysozyme

Enzyme that digests pathogens.

Macrophage

Found in organ tissues. Larger than neutrophils. Chief phagocyte - release interferons and interleukins to signal viral infections. When it comes across an antigen it presents on its cell surface to let adaptive cells to identify it - APC.

Mast Cell

Produced in bone marrow. Found in connective tissues and mucous membranes. Contain large granules that release histamines. Regulate inflammatory response, often associating with allergy and anaphylaxis.

Pathogen

Anything that causes an immune response.

Major Histacompatibility Complex (MCH)

The first complex binds to inhibitory receptors on Natural Killer and turns off killing function (recognized self cells). The second complex takes small proteins that have been digested and migrates them to the surface and displays them as a signal to be picked up by the Adaptive immune cells.

Pathogen-Associated Molecular Patterns (PAMPs)

Generic microbial protein parts present in many variations. Ex. Bacteria capsule pump, peptidoglycan, lipopolyssacharirde.

Pattern Recognition Receptors (PRRs)

Recognizes specific molecular structures on the surface of pathogens. Ex. TLR (toll-like receptors).

Mucous Membranes

Part of the barrier and chemical immune system. Helps prevent pathogens from entering mainly through the nose.

Natural Killer (NK) Cell

Used to combat tumor cells or virus-infected cells. They can attack and destroy potential threats without prior exposure to the pathogen. Releases cytokines that direct other WBC to attack. Looks for a specific protein that all self cells contain. Includes MCH1 (Major Histocompatibility Complex 1) which binds to inhibitory receptors and turns off the killing function.

Neutrophil

Kills bacteria and appears purple. Located in blood tissues. Large numbers released during infections. Phagocytes and contain large dense granulocytes. Dead WBC of this type make up the majority of puss.

Phagocyte

WBC involved in innate immune system. Surface covered in 1000’s of receptors; free floats in blood. Encounters pathogen and receptors bind to protein antigen. Pathogen engulfed and digested by enzymes like lysozyme. Small proteins that remain after being digested are migrated to the surface and displayed by MCH2. Many created by random mutations and are unique.

Phagocytosis

A cellular process where particles are ingested and digested.

Toll-Like Receptors (TLRs)

Membrane spanning and recognizes bacteria pathogen.

Vasodilation

Veins enlarge to allow increased blood flow.