Unit 3: 17.2

Question 1

Chemical mediators

Answer 1

Substances found in body fluids and tissues that inhibits microbes

Question 2

Sebum

Answer 2

Oil that is released from hair follicles onto skin

• endogenous mediator
• seals off pore of hair follicle and prevents bacteria from getting sweat glands and skin
• sebum acts as a food source to resident microbiota and turns sebum into oleic acid (exogenous) making a mildly acidic environment for pathogens

Question 3

Antimicrobial Peptides (AMPs)

Answer 3

Mediators with broad spectrum antimicrobial properties

Question 4

AMP: Bacteriocins

Answer 4

• Secreted by: resident microbiota
• body site: gastrointestinal tract
• inhibits: bacteria
• mode of action: disrupts membranes

Question 5

AMP: Cathelicidin

Answer 5

Secreted by: epithelial cells, macrophages

• Body site: skin
• inhibits: bacteria and fungi
• mode of action: disrupts membrane

Question 6

AMP: Defensins

Answer 6

• Secreted by: epithelial cells, macrophages, neutrophils
• Body site: throughout the body
• inhibits: fungi, bacteria and other viruses
• mode of action: disrupts membranes

Question 7

AMP: Dermicidin

Answer 7

• Secreted by: sweat glands
• body site: skin
• inhibits: bacteria and fungi
• mode of action: disrupts membranes integrity and ion channels

Question 8

AMP: Histatins

Answer 8

• Secreted by: salivary glands
• body site: Oral cavity
• inhibits: fungi
• mode of action: disrupts intracelular function

Question 9

Acute phase proteins

Answer 9

Made in the liver and secreted into blood in response to inflammatory molecules from the immune system

Question 10

Complement system

Answer 10

A group of plasma protein mediators that can act as defense and connects the adaptive immunity
-made of 30 proteins (C1 through C9)
that act as precursor proteins in blood
-innate non specific immunity

Question 11

Complement activation

Answer 11

When complement precursors become functional

-can be triggered by alternative, classical or lectin

Question 12

Alternate pathway

Answer 12

Is activated by complement protein C3

• hydrolysis makes C3a and C3b
• C3b is degraded by water in the blood if no microbes, when there are microbes C3b attaches to surface of microbe and recruit other proteins

Question 13

Classical pathway

Answer 13

More efficient way of activating complement cascade depend on production of antibodies

• a specific antibody must bind to the pathogen to form an antibody antigen complex
• C1 is activated and activates the rest of the complex

Question 14

Lectin pathway

Answer 14

Similar to classical pathway but is triggered by mannose binding lectin (acute phase protein) to carbohydrates in microbial surface
-like acute phase proteins, lectins are made by liver cells and are triggered by inflammatory signals

Question 15

All complement pathways do:

Answer 15

Opsonization, inflammation, chemotaxis, cytolysis

Question 16

Opsonization

Answer 16

Coating of a pathogen in a chemical substance that allows phagocytes cells to recognize engulf and destroy it more easily

Question 17

Membrane attack complex (MAC)

Answer 17

Made of complement proteins C6 through C9

-allows to polymerize into pores in the membranes of gram negative bacteria

Question 18

Cytokines

Answer 18

Soluble proteins that act as communication signals between cells

• autocrine
• paracrine
• endocrine

Question 19

Autocrine

Answer 19

Same cell secretes and receives cytokine signal (self stimulation by a cell)

Question 20

Paracrine

Answer 20

Cytokine signal secreted to a nearby cell

Question 21

Endocrine

Answer 21

Cytokine signal secrets to circulatory system travels to distant cells

Question 22

Three classes of cytokines?

Answer 22

1. Interleukins
2. Chemokines
3. Interferons

Question 23

Interleukins

Answer 23

Interleukins modulate almost every function of the immune system and stimulate cells unrelated to immune defenses

Question 24

Chemokines

Answer 24

Chemotactic factors that recruit leukocytes to sites of infection, tissue damage, and inflammation

Question 25

Interferons

Answer 25

Signaling molecules that are important for defense against viruses -type 1 inferons destroy RNA and stop protein synthesis

Question 26

Histamine

Answer 26

Mediates pro inflammatory events such as airway tightening and contraction of smooth muscle

Question 27

Leukotrines

Answer 27

Lipid based pro inflammatory mediators made from cell membrane of leukocytes and tissue cells -more potent and longer lasting than histamine