20 November: Complement Cascade

Question 1

How does the host “know” that a pathogen is present?

Answer 1

Pathogen-associated molecular patterns (PAMPs)

They basically say “look, you don’t belong here”

Question 2

What are some examples of PAMPs?

Answer 2

LPS, peptidoglycan, lipoteichoic acid, lipid A, flagellin, pilin, viral and bacterial nucleic acid

Question 3

What are PAMPs recognized by?

Answer 3

Pattern-recognition receptors, such as toll-like receptors (TLRs)

Question 4

Where are TLRs present?

Answer 4

On macrophages, dendritic cells, neutrophils, and endothelial cells

Question 5

Where are receptors located?

Answer 5

On the cytoplasmic membrane and the endoscope membrane (within a cell, such as the endoplasmic reticulum)

Question 6

Toxic respiratory burst

Answer 6

Destroys toxic forms of O2 (H2O2, S.O.)

Like oxyclean lol

Question 7

Inflammation

Answer 7

The general, nonspecific response to tissue damage resulting from a variety of causes, including abrasions, cuts, and pathogens

Question 8

What does inflammation cause within cells/

Answer 8

Gaps

Question 9

Signs and Symptoms of inflammation

Answer 9

• Redness in light-colored skin
• Localized heat
• Edema (swelling): usually w/ heat + redness
• Pain (ex. twisted ankle or infection)

Question 10

Complement

Answer 10

Series of proteins in blood (C1, C2, C3….)

Question 11

Classical pathway

Answer 11

Antibody-Microbe complex triggers complement cascade

Question 12

Alternative pathways

Answer 12

Pathogen surface binds to C3

Question 13

Lectin Pathways

Answer 13

Lectin-coated pathogen surface binds to C4 + C2

Question 14

What do all the pathways activate?

Answer 14

C3 convertase

Question 15

C3 convertase cuts C3 into what?

Answer 15

C3a and C3b, which have different functions

Question 16

C3a

Answer 16

Capillaries, triggers inflammation, brings phagocytes that destroy bacteria along with antimicrobial peptides, interferons, complement, iron-binding proteins

Question 17

C3b

Answer 17

Bind to bacteria, Opsonin

Question 18

Opsonin

Answer 18

Enhances phagocytosis

Question 19

Membrane Attack Complex (MAC)

Answer 19

C5b will land on bacteria + will bind to C6, C7, C8 + C9 and will form a circle in bacteria + ultimately make a hole

The cell will lyse then die. (apoptosis)

Question 20

Lymphatic System

Answer 20

Collects fluid from tissues + are filtered by lymph nodes + spleen

Question 21

Slow eaters

Answer 21

Macrophages + dendritic cells

Sloppy too (kill others around them)

Question 22

Filopodia

Answer 22

What dendritic cells have; basically it “reaches blindly into a bag and grabs random things”

Question 23

C3B

Answer 23

Activates C5 Convertase