Innate and Adaptive Immunity

Question 1

When an infection occurs what is the pathway of immune response? how many hours into the infection does each occur?

Answer 1

1. 0-4 hours innate response (barriers and non specific effectors)
2. 4-96 hours is the induced innate response. Here pathogenic associated molecular patterns (PAMPS) are recognized and inflammation occurs.
3. Adaptive immune response occurs after 96 hours. This is B and T cell activation.

note not all 3 always occur. Depends on how far a infectious particle can survive.

Question 2

What are the three main portions of the innate immune response?

Answer 2

1. physical barriers such as the skin and mucosal tissue
2. chemical barriers such as stomach acid and lysozyme’s (kill bacteria non-specifically)
3. cellular response via PAMP’s

Question 3

What is the immune anatomical barrier?

Answer 3

skin
respiratory tract
GI tract
eyes, nose, mouth

note: lysozyme’s and defensins are considered apart of the anatomical barrier.

Question 4

what are sebaceous glands?

Answer 4

glands that secrete oil into hair glands which have innate immune function.

Question 5

What are toll like receptors and where are they found?

Answer 5

Toll like receptors are found on the surface of epithelial cells where they “taste” whats in the GI tract. They recognize PAMP’s. they are apart of innate immunity.

They can also be found on macrophages

Question 6

explain mucosal innate immunity?

Answer 6

• lysozyme’s chew up bacteria in mucous
• goblet cells make mucous
• toll like receptors test for PAMPS
• lamina propria contains other immune cells

Question 7

what are defensins?

Answer 7

both lysozyme’s and defensins are constitutively secreted by epithelial cells. Defensins are microbial peptides that kill bacteria and some viruses

Question 8

what is the main difference between gram positive and gram negative bacteria?

Answer 8

gram positive LACK an outer membrane and have a much larger peptidoglycan layer. Therefore lysozyme’s effect gram positive much more.

Question 9

what is LPS, where is it found?

Answer 9

it is a PAMP found on gram negative bacteria.

Question 10

How do defensins function as opposed to lysozyme’s? What pathogen are they most effective against?

Answer 10

Defensins are conserved peptides that are amphipathic. They work by entering the membrane of a bacteria or virus and creating a leaky pore.

• they are efficient against enveloped viruses.

Question 11

what type of immune response usually first occurs if a pathogen passes the anatomical barriers?

Answer 11

inflammation.

Question 12

explain the general steps of inflammation.

Answer 12

1. a macrophage in tissue recognizes a PAMP
2. this causes the macrophage to release cytokines and chemokines
3. vasodilation + increased permeability occurs and allows fluid and other immune cells to swell the tissue
4. redness, pain, and swelling observed

Question 13

What are the three main types of innate immune cells. What does each do briefly?

Answer 13

Neutrophils –> arrive the fastest and are efficient at early phagocytosis and killing ingested microbes

macrophages / monocytes –> they are responsible for phagocytosis and releasing cytokines which recruit other immune cells and stimulates inflammation.

NK cells –> kill infected cells via lysis.

Question 14

what is the difference between macrophages and monocytes?

Answer 14

macrophage –> found in tissue

monocyte –> found in circulation

they both express cell surface receptors (along with neutrophils) which recognize pathogens for phagocytosis.

Question 15

what is phagocytosis?

Answer 15

engulfment and internalization of materials such as microbes for their clearance and destruction.

Question 16

Explain

attachment 
ingestion 
fusion 
digestion
release

Answer 16

attachment: pathogen binds macrophage membrane
ingestion: membrane surrounds the pathogen
fusion: the phagosome fuses with a lysosome.
ingestion: lysosome peptides destroy the peptide.
release:

Question 17

What is opsonization?

Answer 17

this is a way to accelerate the phagocytic process. Here molecules bind and surround the pathogen. These are now “Surface” proteins that are recognized by surface receptors of the macrophage.

for example: antibodies can cover a microbe (in this case the antibodies are opsonins) and macrophage Fc receptors will bind the antibodies and eat the microbe.

Question 18

t or f, opsonins must be specific.

Answer 18

false, e.g. not all opsonins are antibodies

Question 19

how to NK cells work?

Answer 19

they bind to infected cells and release cytotoxic granules which creates perforations in the cell. This induces apoptosis.

Question 20

What are the soluble proteins and cells of innate and adaptive immunity?

Answer 20

innate
soluble proteins –> lysozyme’s, defensins, complement, cytokines
cells –> neutrophils, macrophages, NK cells

adaptive
soluble proteins –> antibodies
cells –> B and T cells

Question 21

true of false, innate and adaptive immune receptors are received in the germ line.

Answer 21

false, only innate are. The adaptive receptors are rearranged and therefore not identical.

Question 22

what are dendritic cells?

Answer 22

they are innate cells which act as a scaffold between the innate and adaptive immunity. They bring infectious material too lymph area’s and present it to T cells. The T cells differentiate into pathogen specific subsets.

Question 23

what are two innate processes that occur in conjunction with adaptive immunity?

Answer 23

opsonization –> antibodies coat microbe and macrophage eats it.

compliment system

also, some adaptive cells have toll like receptors which allows them to release cytokines upon binding

Question 24

Explain Adaptive immunity:

1. specificity
2. discrimination
3. diversity
4. self-limitation
5. memory

Answer 24

1. adaptive response is very pathogen specific. Distinct microbes elicit distinct T and B cells
2. Discrimination –> recognize self vs non-self
3. diversity –> T and B cells respond to a large variety of pathogens
4. self limitation –> ensures that once infection cleared our body goes to basal limits (unless autoimmune)
5. memory –> prevents reinfection

Question 25

true or false, innate immunity is inborn, unchanging, nonspecific.

Answer 25

true

Question 26

what is humoral response and what is cell-mediated response?

Answer 26

homoral –> B cell activation and production of antibodies

cell-mediated –> ABC’s and T cell activation