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Question 1

Where do most microbes enter?

Answer 1

Mucosal surfaces, such as respiratory, gastrointestinal and urogenital tracts

Question 2

Tissue injury and disease is caused normally by the microbe and the toxins produced by it. True or false?

Answer 2

False. Most of the times, the problems of a disease are actually caused by the immune system going all scorched earth and fucking up everything

Question 3

If a bacteria reproduces outside of the blood (for example, in a connective tissue), then it is considered an intracellular bacteria. True or false?

Answer 3

False. Extracellular bacteria reproduce outside host cells, such as in the blood, connective tissue or tissue spaces like the lumen.

Question 4

What is the difference between an endotoxin and an exotoxin?

Answer 4

Endotoxins are bacterial cell wall components

Exotoxins are secretions by the bacteria

Question 5

What are the three main innate mechanisms of fighting extracellular bacteria?

Answer 5

The main mechanisms are complement activation, phagocytosis and the promotion of an inflammatory response

Question 6

Each innate compliment activation pathway leads to a different outcome. True or false?

Answer 6

False. They all converge to a production of C3b opsonin, C3a and C5a anaphylatoxins, and C5b-9 (Mac)

Question 7

What is the function of C3b opsonin?

Answer 7

It binds to the surface of microbes and facilitates pathogen phagocytosis

Question 8

C3b and C3a originate from the cleavage of a C3 molecule. True or false?

Answer 8

True

Question 9

C3a and C5b-9 induce vessel vasodilation during an inflammatory reaction. True or false?

Answer 9

False. It’s C3a and C5a

Question 10

What bioactive molecule produced from an innate complement activation induces direct lysis of pathogens during the resolution phase of inflammation?

Answer 10

It’s C5b-9 (Membrane attack complex)

Question 11

Both the classical pathway and lectin pathway require antibodies to begin. True or false?

Answer 11

False. Only the classical pathway needs it.

Question 12

In the lectin pathway, a mannose-binding lectin binds to the mannose expressed by host cells. True or false?

Answer 12

False. it binds to the mannose produced by microbes.

Question 13

Innate immunity to extracellular bacteria, the alternative pathway can be activated by the presence of a gram-positive bacterial cell wall component or a gram-negative bacteria wall component, such as a peptidoglycan or LPS respectively. True or false?

Answer 13

True

Question 14

For an inflammatory reaction, the leukocytes are recruited and activated by C___ and C___

Answer 14

C5a and C3a

Question 15

Macrophages cannot directly recognize bacteria, but neutrophils can. True or false?

Answer 15

False. Both of them can recognize them directly through mannose and scavenger receptors.

Question 16

How is an extracellular bacteria detected indirectly?

Answer 16

Via fc and complement receptors that detect opsonized bacteria

Question 17

When an extracellular bacteria gets phagocyted, the phagosome with the ingest microbe is “filled” with ROS, Nitrogen Species and enzymes to kill the bacteria. True or false?

Answer 17

False. First, the phagosome fuses with a lysosome (forming a phagolysosome) and THEN this compartment is filled with ROS, Nitrogen Species and enzymes to kill the bacteria.

Question 18

DCs and phagocytes start secreting pro-inflammatory cytokines which promote leukocyte infiltration into the sites of infection. These leukocytes then ingest and destroy the bacteria. True or false?

Answer 18

True

Question 19

leukocyte infiltration into sites of infection is what causes inflammation. True or false?

Answer 19

True

Question 20

ILC_ activated by ______ produced in response to microbes secrete _____, ______, and ______, which enhances epithelial function and recruitment of ____________

Answer 20

ILC3
cytokines
IL-17, IL-22 and GM-CSF
neutrophils

Question 21

To neutralize, opsonize/phagocyte and activate components, the innate immune system utilizes IgG, IgM, and IgA. True or false?

Answer 21

False. The ADAPTIVE immune system utilizes this.

Question 22

What is the function of CD4 helper T cells against extracellular bacteria?

Answer 22

They produce cytokines
Enhance phagocytic and microbicidal activity of macrophages and neutrophils
Stimulate antibody production
And MOST IMPORTANTLY:
Th17 responses: Recruiting neutrophils and monocytes to promote local inflammation

Question 23

A patient with defective Th17 is more susceptible to _________________

Answer 23

extracellular bacteria and fungi

Question 24

Hey, I thought the immune system was a good guy. How does it cause tissue damage to US?

Answer 24

Local production of reactive oxygen species and lysosomal enzymes

Question 25

What are the main septic shock contributing cytokines?

Answer 25

TNF, IL-6 and IL-1

Question 26

What is the problem with a superantigen?

Answer 26

They result in a normal antigen reaction but on steroids, which means WAY more T cells and WAY more cytokines being produced, which results in more tissue damage.

Question 27

One of the problems with superantigens is that they bind outside of the peptide-binding groove of the MHC II. True or false?

Answer 27

True

Question 28

How does a Rheumatic fever occur?

Answer 28

Through molecular mimicry, in which the antibodies designed against a certain protein cross react with proteins from the heart.

Question 29

How can bacteria "fight" or "avoid" the host immune system?

Answer 29

Through antigenic variation Inhibition of complement activation Resistance to phagocytosis Scavenging of reacting oxygen species

Question 30

What is a serotype?

Answer 30

Its a strain

Question 31

Neisseria is an interesting bacteria. Why?

Answer 31

Because it has different ways of evading the immune system. Such as: Changes in the surface antigens over time Decoy membrane "blobs"

Question 32

Bacteria can alter the host's metabolism to avoid the immune system. True or false?

Answer 32

True

Question 33

How does S. aureus avoid being killed by neutrophils?

Answer 33

It elicits a specific metabolic response that impairs their ability to kill the bacteria

Question 34

How does genetic variation of the immune system affect extracellular bacteria?

Answer 34

It affects molecules involved in innate recognition and humoral immunity

Question 35

A deficiency in a certain molecule can affect a specific type of bacteria, causing the infections by said bacteria to be more frequent, while keeping other bacteria roughly the same. True or false?

Answer 35

True