From Innate to Adaptive Immunity

Question 1

Define PRR:

Answer 1

Pattern-recognition receptor (PRR): proteins on the cell surface expressed by cells of innate immune system to identify pathogen-associated molecular patterns (PAMPs)

Question 2

Define PAMPs:

Answer 2

Pathogen-associated molecular pattern (PAMP): foreign molecular structures on pathogens (bacterial cell wall protein, bacterial dsRNA) that are recognized by PRRs in the innate immune system

Question 3

Define TLR:

Answer 3

Toll-like receptor (TLR): type of PRR, protein that recognize a foreign molecular structure that humans don’t have, there are a least 10 TLRs.

Question 4

What are examples of TLRs?

Answer 4

TLR4 bines lipopolysaccharide (part of bacterial cell wall), TLR2 bind peptidoglycan (bacterial).

Question 5

Define DAMP:

Answer 5

Damage-associated molecular pattern: stress or damage indicators expressed by body cells (paintball example from Cohen).

Question 6

Name some common foreign patterns recognized by TLR.

Answer 6

TLR1: lipopeptide (bacterial), TLR2: zymosan (fungal), TLR3: dsRNA (viral), TLR4: endotoxin=lipopolysaccharide, TLR5: flagellin (bacterial flagellum), TLR6: lipopeptide (mycoplasma), TLR7: ssRNA (influenza), TLR8: ssRNA (viral), TLR9: unmethylated CpG (herpes virus), TLR10: asthma connection

Question 7

Identify the final transcription factor that is most commonly activated in inflammation.

Answer 7

Bad bug makes endotoxin –> endotoxin binds to a variety of things and then ultimately recognized by TLR –> Signal cascade –> activates NF-KB –> inflammation

Question 8

The factors made by the PAMP-stimulated cell are called _______ and _______. As cells get damaged and stressed, they release certain of their internal molecules (the _______), and some _______ bind them, too, increasing the local inflammation.

Answer 8

• cytokines
• chemokines
• DAMPs
• TLRs

Question 9

What are chemokines?

Answer 9

(Greek -kinos, movement) are a family of small cytokines, or proteins secreted by cells. Their name is derived from their ability to induce directed chemotaxis in nearby responsive cells; they are chemotactic cytokines. When these are released, WBC head towards it because they like areas of high concentration, like they like pizza

Question 10

What are cytokines?

Answer 10

(Greek cyto-, cell; and -kinos, movement) are small cell-signaling protein molecules that are secreted numerous cells of the immune system and are a category of signaling molecules used extensively in intercellular communication. Cytokines can be classified as proteins, peptides, or glycoproteins; the term “cytokine” encompasses a large and diverse family of regulators produced throughout the body by cells of diverse embryological origin. Generally help inflammation.

Question 11

Describe the function of the innate immune response (4)

Answer 11

a. You are born with innate immunity, therefore it is very limited in its actions and NOT adaptive (can’t change with different threats).
b. It detects intruders via molecular motifs/chemical structures found in pathogens, for humans, such motifs would include components of bacterial cell walls (us eukaryotes don’t have cell walls, of course), and odd microbial nucleic acid patterns. This is achieved by pattern recognition receptors
c. The intruders have ventured too deep into our body’s structures and then innate immune system arranges for their inactivation, destruction and removal.
d. Most immune responses are innate, but if it becomes overwhelmed, then adaptive response kicks in. The innate response is required to activate the adaptive response

Question 12

Name and describe the cell that forms the bridge between innate and adaptive immunity.

Answer 12

a. Dendritic cells: phagocytic cells at the interfaces between the body and the world (skin, lung, mucous membranes—where bad stuff can enter). At wound site, immature DCs get activated by the cytokines and chemokines secreted from the innate immune response, and they take up anything they can including foreign molecules derived from invaders. Activated (mature) DCs leave the local wound area and travel in the lympatics to the nearest/first lymph node (known as the DRAINING lymph node). Here they “show” what they have eaten to lymphocytes (the present the antigen). In the lymph node, adaptive immune response develops with the presence of T cells, B cells, and DCs. Adaptive immune response CANNOT develop in the periphery

Question 13

Immature dendritic cells are

Answer 13

the best phagocyte ever

Question 14

mature dendritic cells are

Answer 14

the best antigen present cell ever