Topic 2

Question 1

What are the 3 main Innate immunity types?

Answer 1

barriers (epithelial cells), cellular defenses, chemical defenses.

Question 2

What types of Innate immunity barriers are there?

Answer 2

physical barrier prevents entry, low pH retards growth, epithel. cell mucous secretion traps microbs, cilia propel microbes out, body temp inhibits microbe growth, fever response inhibits growth, epithelial cells secrete anti-microbial compounds (lysozyme, defensins, type I interferon, etc.).

Question 3

What Innate internal barriers exist and where are they located?

Answer 3

cilia, mucous, stomach acid, normal flora, etc. found in lungs, hair follicle, gut, etc.

Question 4

What are some ways to break physical barriers?

Answer 4

surgery, gunshot, broken bone, catheter, burn, etc.

Question 5

How does Complement system activation occur and when?

Answer 5

Can be innate or adaptive, by circulating or membrane bound proteins. The enzymes are activated when a microbe binds.

Question 6

What is Chemotaxis?

Answer 6

Chemotaxis attracts macrophages and dendritic cells, and others innate immunity cells which leads to inflammation (C3A, a chemoattractant).

Question 7

What is Opsonization?

Answer 7

C3B is deposited on a microbe which makes it more detectable by macrophages

Question 8

What is Lysis?

Answer 8

Various proteins form membrane attack complex (MAC) on the microbe which opens its membrane leading to lysis (popping a balloon).

Question 9

What kinds of Cellular receptors for microbes are there? Where are they found? What are the results of a microbe binding a receptor in the innate system?

Answer 9

TLRs, mannose receptors, n-formyl methionyl, and scavenger receptors, Lectin. Found on macrophages, lymphocytes, dendritic cells, epithelial cells, endothelial cells. Different receptors are specific to different kinds of microbes.

Receptor=signal=nucleus=gene activation=interferon production, adaptive immunity stimulizatino, inflammation (quick), and cleavage of inactive proteins to start cascade.

Question 10

What are some basic Innate system characteristics

Answer 10

Does not recognize self

Not specific, always present, always constant

Acts the same way each time and acts quickly-inflammation and anti-viral (NK and Interferon)

Directed at structures of microbes necessary for survival or infectivity (thus microbes can’t mutate those aspects of themselves).

Question 11

Innate system differences from adaptive

Answer 11

Aimed at structures shared by classes of microbes, not specific microbes

Limited diversity in receptors

does not recognize self ever

Question 12

Basic characteristics of Neutrophils

Answer 12

PMNs, most abundant in blood, increase in number in response to cytokines. First responders of inflammatory cells. Predominant cells in pus. Kill microbes by phagocytosis and degranulation. Short life span. Important at clearing bacterial infections.

Question 13

What are the steps of Macrophage Differentiation

Answer 13

BM stem cell=blood monocyte=tissue macrophage=different names in different tissues

Question 14

what are the two kinds of Macrophage Activation and how are they different?

Answer 14

Classically activated (M1) are proinflammatory and eat bacteria and fungi

Alternatively activated (M2) are involved in wound repair and fibrosis and are anti-inflammatory.

Question 15

What are the steps in Macrophage Function

Answer 15

Bind microbe w/ lectin or scavenger receptors=ingest the phagosome=fuse with lysosome=destroy microbe with ROS, NO, and lysosymal enzymes.

Question 16

NK Cell Functions

Answer 16

Open pore in virus infected cell and secrete enzymes into it to kill it.

Produce cytokines to activate macrophages

Kill phagocytosed microbes.

Question 17

How is NK Activated? How do the NK receptors know to kill a host? How do NK cells interact with macrophages?

Answer 17

Can kill host cells directly.

macrophages secrete cytokine which urges NK cells to produce cytokine which activates macrophage to kill microbe.

When a virus enters a cell, it turns the inhibitory receptors (class I MHC) off. Thus when activating receptors are much more abundant than inhibitory receptors, upon binding, the NK cell will kill the host cell.

Question 18

What do Dendritic cells do? What types are there and how do they differ?

Answer 18

Phagocytose and kill microorganisms. Myeloid, lymphoid, and plasmacytoid dendritic cells all produce different cytokines/IFNs.

Question 19

Where are Mast cells located and what is their main function?

Answer 19

Present in most tissues near blood vessels, espeically near outside world.

Essential for inflammation. When activated, it releases granules and hormonal mediators into interstitium.

Eosinophils and basophils also help with inflammation

Question 20

What is the function of Type I IFN?

Answer 20

Cytokine which blocks viral replication. An infected cell sends type I IFN to a neighbor cell which activates its antiviral machinery making it harder to infect it.

Question 21

What are cytokines? What cells produce them? How do cytokines work in innate immunity? What can happen if they are overproduced?

Answer 21

Soluble signaling molecules, mostly interleukins produced by leukocytes.

Produced in small concentration, primarily by activated macrophages, and have autocrine and paracrine function.

Overproduction can lead to septic shock.

Question 22

Steps of innate immunity to Cellular and chemical response to physical barrier being compromised

Answer 22

Recognize pathogen (various receptors on macrophages and dendritic cells)=respond to pathogen (activate macrophage, release cytokines and chemokines so complement proteins enter from blood)=recruit cells to site (chemokines made, neutrophils/monocytes recruited)=resolve the immune response (pathogen gone, less stimulus, produce cytokines to reduce permeability, promote tissue repair).

Question 23

What are the steps of inflammation?

Answer 23

Macrophages recognize microbe, release cytokine IL-1 and TNF=Cytokines act on endothelium to express selectins=Selectins weakly bind PMNs and Monos which roll along the wall=Chemokines are produced which eventually leads to a more stable adhesion due to integrins=eventually the chemokines direct the cells through the wall to the site of infection=PECAM-1 helps with leukocyte diapedesis=integrins in EC matrix also help bring leukocytes to right site in tissue.

Question 24

Reason for Adaptive

Answer 24

Innate mechanisms overwhelmed or compromised, some microbes find ways to get passed it.