Innate defenses of mucosal surfaces

Question 1

what are the 3 main defenses of mucosal surfaces

Answer 1

1 - innate immunity
2 - adaptive immunity
3 - nonspecific barrier defenses

Question 2

how are gram-negative mucosal pathogens transmited ?

Answer 2

SEVEN F’s

feces, food, fluids, fingers, flies, fomites, fornication

Question 3

what gram negative bacteria can cause disease at small innoculum size ?

Answer 3

Shigella dysenteriae

Question 4

what gram negative group needs a larger inoculum size to cause disease

Answer 4

salmonella

Question 5

what are some of the natural barrier defenses (anatomical and physiological) of the GI tract

Answer 5

acidity changes (stomach vs. intestine)
motility of fluids (peristalsis)
mucous layer and glycocalyx
tight junctions

Question 6

why are there more bacteria found in the large intestine compared to the small intestine

Answer 6

the motility of fluids is slower in large intestine, thus easier for bacteria to attach to

Question 7

why are humans not ALWAYS infected with gram negative bacteria

Answer 7

Cuz there are many good gram negative bacteria in body, and those microbes take up potential attachment sites before bad bacteria

Question 8

what is a lysozyme and how does it work ?

Answer 8

secretory antimicrobial compound that cleave beta 1,4 bonds

-kills murein (which makes peptidoglycan) so essentially kills gram positive bacteria

Question 9

what is a lactoferrin and what does it do

Answer 9

secretory antimicrobial compound that sequesters iron (so bacteria cant use to make virulence factors)

Question 10

what is cathelicidin and what does it do

Answer 10

secretory antimicrobial compound that disrupts both gram + and - bacterial membranes and then lyses them

Question 11

what are defensins and what are the 2 types

Answer 11

secretory antimicrobial compounds that target microbe immune systems

• alpha-made by immune cells
• beta - made by epithelial cells

Question 12

what are the 3 strategies that pathogenic bacteria use to overcome innate barrier defenses

Answer 12

• acid resistance (to get them through stomach)
• fimbriae/pili (allow for attachment and not washed off)
• bacterial structures to combat antimicrobial compounds

Question 13

once a pathogenic bacteria gets across the hosts mucous membrane, what is the next and most important line of defense

Answer 13

macrophages which recognize, engulf, and kill

Question 14

how do macrophages detect when foreign pathogenic bacteria have entered the cell

Answer 14

have pathogen recognize receptors that recognize PAMP’s

Question 15

what are PAMP’s

Answer 15

pathogen associated molecular patterns (on bacteria)

Question 16

what specific pathogen recognition receptor recognizes LPS (type of PAMP’s) in gram negative bacteria, and is the main receptor for defense vs. gram negative bacteria

Answer 16

TLR4

Question 17

once macrophages are activated, what else do they signal

Answer 17

signal cytokines which signal other immune cells

Question 18

what is the negative side of macrophages signalling the cytokine inflammatory response

Answer 18

cytokines can disrupt tight junctions of epithelial cells making it easier for microbes to penetrate mucosal layer

Question 19

what are siderophores and who do they help

Answer 19

they sequester iron for the bacteria in low iron environments
-combats lactoferrin antimicrobial compound

Question 20

some bacteria develop capsules once they are inside the cell, what would this help avoid ?

Answer 20

phagocytosis

Question 21

the adaptive immune response of the human body is generated where ?

Answer 21

in the lymph nodes

-densest clusters of lymph nodes are located near mucosal membranes