Oral Immunity & Host Defenses

Question 1

What does an accumulation of dental plaque induce?

Answer 1

inflammatory response in gums -> inflammation in pulp may lead to abscess & root canal
*dental diseases result from imbalance between oral commensal bacteria and immune responses

Question 2

What is the general concept of host defenses?

Answer 2

in oral cavity it consists of both mucosal and systemic immune systems

Question 3

What are the physical barriers in oral cavity?

Answer 3

epithelial cells with tight junctions, basement membrane below

Question 4

What is in saliva to help protect against microbes?

Answer 4

mucins, a & B defensins, protease inhibitors, lysozyme, lactoferrin, peroxidases

Question 5

What is the enamel pellicle?

Answer 5

protects teeth from demineralization & friction, however contributes to plaque formation, made of mucins, secretory IgA and other proteins

Question 6

In MALT, what does secretory IgA in saliva do?

Answer 6

neutralize toxins & pathogens, binds pathogen and transported through lamina propria by M cells to induce an immune response

Question 7

In MALT, what is homing?

Answer 7

activated lymphocytes enter circulatory system -> enter infected mucosa

Question 8

What is the Systemic Immune System of Oral Immunity composed of?

Answer 8

leukocytes in pulp and gingival crevice, lymph

Question 9

How is the inflammatory response induced when caries approach pulp?

Answer 9

neutrophils enter pulp from blood -> B cells migrate into pulp -> inflammation helps prevent damage to pulp -> abscess or lesion forms

Question 10

What is the importance of the gingival crevice?

Answer 10

it is the major site where leukocytes enter saliva (in gingival crevicular fluid)

Question 11

How does gingival crevicular fluid function in response to plaque?

Answer 11

after leukocytes from MALT, is part of systemic system so it mixes with the mucosal system (saliva), increases flow and changes composition, increase leukocytes within gingival sulcus (especially neutrophils)

Question 12

How can pathogens be classified?

Answer 12

where infection occurs

Question 13

Recovery and resistance requires what type of immunity?

Answer 13

acquired, although responses may differ

Question 14

Can a wrong immune response be lethal?

Answer 14

yes, especially T cell response

Question 15

Where are extracellular pathogens found?

Answer 15

within body fluids or attached to epithelial cells

Question 16

Where are intracellular pathogens found?

Answer 16

cytoplasm or vesicles

Question 17

What are the four types of pathogens?

Answer 17

bacteria, fungi, virus, parasite

Question 18

What are the defenses against bacteria?

Answer 18

neutralizing antibodies prevent attachment, opsonization of pathogen, classical complement pathway, neutralizing antibodies against bacterial toxins, activation of macrophages by Th1 CD4+ T cells, cytotoxic CD8+ T Cells kill infected cells

Question 19

What type of pathogens are viruses?

Answer 19

extracellular before infecting, then intracellular

Question 20

How are virus infections categorized?

Answer 20

acute infection, latent with reactivation, chronic

Question 21

What is the defense against acute virus infection?

Answer 21

viruses eliminated, cell mediated immunity is important for recovery, antibody stops virus from spreading and may render host resistant to reinfection

Question 22

What is the defense against latent virus infections with reactivation?

Answer 22

virus persists in latency, cell mediated immunity clears infected cells, as well as antibodies prevent spreading when reactivation does occur

Question 23

What is the defense against chronic virus infections?

Answer 23

virus not eliminated nor latency, disease may be limited by immune response

Question 24

What are the categories of fungal infections?

Answer 24

cutaneous, systemic

Question 25

What is the defense against fungi (mycoses) both cutaneous and systemic?

Answer 25

cutaneous: neutrophils & macrophages control infection
systemic: antibodies & cell-mediated responses are important

Question 26

What is characteristic of parasitic infections?

Answer 26

usually chronic, protozoa may be extra or intracellular, have complex life cycles

Question 27

What is the defense against protozoa parasites?

Answer 27

antibody defenses are most effective against extracellular, cell-mediated for intracellular

Question 28

What is important to kill parasitic flatworms and nematodes?

Answer 28

eosinophils

Question 29

What are prions and how are they defended?

Answer 29

protein misfolds cause brain disease, little or no immune response because converted prions are self proteins