Mar26 M2-Infection and immunity

Question 1

things that influence the symptoms of a disease with inflammation

Answer 1

• immune system impaired
• infant (not same symptoms as adults)
• being on a statin

Question 2

biologic drugs used in many diseases: what they do

Answer 2

immune system modifiers

Question 3

statins effect on the immune system

Answer 3

• compromise the immune system

- compromise macrophages (supposed to cause plaque rupture). ats not stopped but plaque rupture stopped

Question 4

fever, malaise, was in quinolone resistant malaria strain area when travelled in Africa = number 1 on ddx

Answer 4

acute viral illness infection (malaria is only number 2)

Question 5

concept of route of infection in the body

Answer 5

• diff routes of entry of pathogens (airways, GIT, reproductive tract, external surface, wounds, insect bites)
• each route has its pathogens

Question 6

important pathogens in airway, GIT and reproductive tract routes

Answer 6

airways = influenza
GIT = salmonella, rotavirus
reproductive tract = HIV, treponema pallidum

Question 7

4 classes of pathogens

Answer 7

1. EC bacteria, parasites, fungi
2. IC bacteria, parasites
3. viruses (IC)
4. parasitic worms (EC)

Question 8

1st symptom of malaria

Answer 8

periodic fever

Question 9

malaria type of infection

Answer 9

intracellular parasitic infection (enters and lives in RBCs)

Question 10

immunologicla charact of RBCs

Answer 10

no MHC 1, malaria invisible to immune system in RBC. when RBC full, bursts, malaria goes in other RBCs

Question 11

how microbes get through epithelial barriers of the body

Answer 11

1. mechanical effects (cuts, breaks, bites)
2. chemical (they can secrete stuff to compromise our barrier)
3. compromised gut flora (serves as protection normally)

Question 12

factors that influence the incubation period of a virus (3)

Answer 12

• amount of inoculum you got (how much virus)
• virulence of the infection (how many substances released and that serve as stimulus)
• immune system reaction

Question 13

3 steps of immune response after infection (3 time categories)

Answer 13

• innate immunology (0-4 hours) = non specific receptors
• early induced response (4-96 hours) = PAMPs
• adaptive immune response (clonal expansion of B and T cells)

Question 14

when does adaptive immune system act in infection and how long before you see an Ab

Answer 14

• doesn’t act until at least 4 days

- see first Ab after 2 weeks

Question 15

there’s a certain level of Ag needed for the adaptive immune response to be involved: name of that concept

Answer 15

antigenic window (is a threshold) (at threshold, end of incubation period)

Question 16

def of incubation period

Answer 16

time to onset of symptoms = time to threshold (of adaptive immunity)

Question 17

(imp) 5 acute phase cytokines + def of that

Answer 17

• cytokines released first and that cause the first blush of symptoms
• IL-1, IL-6, IL-8 (CXCL8), IL-12, TNF-alpha

Question 18

why route of infection is key in immunity

Answer 18

• will try to localize infection to its original site
• systemic dissemination and infection that spreads = LOT of inflam + HARD to target (bc cytokines released everywhere by macrophages = confusing for neutrophils)

Question 19

what helps localize an infection to its original site

Answer 19

antibodies

Question 20

liver role in inflammation

Answer 20

produces acute phase reactants

• platelets
• CRP (acts as an opsonin on bacteria + activates the complement). important for abcesses bc they can hide

Question 21

abscess management and prognosis if watch and wait

Answer 21

management = drain, give Abx, until microbes gone

watch and wait = abscess will win and spread

Question 22

3 things that can happen if you stop Abx (for an abscess for ex) too soon (the 3 Rs)

Answer 22

1. reappearance of the abscess
2. resistance (if new microbe grows again)
3. regrowth

Question 23

how to follow an abscess and know when it’s gone

Answer 23

watch CRP and follow until back to normal

Question 24

CRP still elevated after normal Abx time 2 things to do

Answer 24

1. rethink dx

2. continue Abx

Question 25

most common pathway to deal with viruses

Answer 25

1. virus infected host cell releases IFN-a and IFN-b
2. resistance to viral replication in all cells
3. more MHC class 1 expression
4. NK cells activation

Question 26

3 immune branches involved in virus elimination (in order) and ones that are more involved

Answer 26

1. IFN-a, IFN-b, TNF-a, IL-12 production + NK-cell mediated killing of infected cells (Most of the job)
2. T cell mediated killing of infected cells

Question 27

2 advantages of infected cell killing (virus) with T cells (CD8)

Answer 27

1. cell implodes (apoptosis)

2. protects surrounding

Question 28

consequence of a disease of macrophage activation

Answer 28

• primary immunodeficiency

- can get adenitis (lymph node infection) bc macrophage engulfs bacteria but doesn’t kill it

Question 29

time before primary immune response really acts vs secondary immune response

Answer 29

12 days

secondary = immediately

Question 30

why secondary response is faster and stronger

Answer 30

faster bc of memory cells
stronger bc of somatic hypermutation
*only high affinity cells and high affinity memory cells remain at end of primary response

Question 31

substance that marks, flags microbes in the body

Answer 31

antibodies

Question 32

4 things Abs do

Answer 32

1. neutralization + eventually leads to ingestion by macrophage
2. opsonization (coat + macrophages eat)
3. complement
4. independent Ab mediated cell toxicity (target pathogen bound with Ab for other cells)

Question 33

4 ways microbes can make you sick (4 sites)

Answer 33

• interstitial spaces, lymph, blood
• epithelial surfaces
• cytoplasmic
• vesicular (IC)

Question 34

whooping cough like pertussis, diphteria and others, why makes you sick

Answer 34

Are toxemias. it’s the toxin that causes the cough.

Question 35

2 most common causes of death in influenza

Answer 35

• secondary bacterial infection

- heart attack

Question 36

how long influenza effect can last

Answer 36

4 months

-can show up with pneumonia 4 months after infection

Question 37

HIV infects what cells in the body

Answer 37

CD4+ T cells (helper)

Question 38

CASE: fever, malaise, was in quinolone resistant malaria strain area when travelled in Africa: investigation

Answer 38

smear for malaria (viral infection still #1 on ddx)

Question 39

name of healthy infection

Answer 39

commensals