Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MICI 2100 > Lec 21-Immunity To Parasites > Flashcards

Lec 21-Immunity To Parasites Flashcards

1
Q

Immune sys and parasites

A
  • Immune sys is designed to fight parasites
  • When immune sys cant fight parasites anymore = infection
  • Parasitic infections are especially prevalent in tropical/subtropical regions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are parasites?

A
  • Microorganisms
  • Can infect humans (via contact, inhalation, ingestion), arthropods (act as vectors of transmission i.e. mosquitos), nonhuman primates (zoonotic spread)
  • Parasites are a big challenge for the immune sys, harder to get rid of than viruses—they have many diff forms which makes it hard for immune sys to detect
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

2 main groups of parasites

A

2 main groups: protozoans (unicellular, eukaryotic) and metazoans (helminths/worms)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the primary reason parasites are such a big challenge for the immune system?

A

Parasites change their antigenic structure and their location over time to evade immune response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Entry points for parasites

A

Resp tract, GI tract, vaginal tract, anal tract, conjunctiva, epidermis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Eg. Parasites changing location to evade immune response

A
  • Lots of variability, can be in many vectors
  • Worst diseases caused by protozoan parasites that are unicellular, motile eukaryotes. They can be found in contaminated water
  • Protozoan parasites can move from their arthropod vector hosts to mammalian hosts to infect them
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Why are parasites bad

A
  • Parasitic infection is endemic/epidemic in LDCs. In MDCs we would have 0 immunity to anything like this so we would die
  • Multicellular parasites influence host immune response—eg. Co-infection with a parasite and a virus/bacteria is very dangerous
  • Eg. Malaria (parasitic infection) kills 2-5 mill children a year
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Endemic vs epidemic vs pandemic

A

Endemic: in 1 area
Epidemic: many geo locations in 1 country
Pandemic: has spread across world

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Trypanosomes eg

A
  • Trypanosomes are parasites that can evade immune response by changing antigenic signature
  • Host is infected with trypanosome expressing VSG1 protein. As body begins to act against this protein, tryp shuts down VSG1 and begin expressing VSG2 (diff structure), so immune sys mounts a diff response against VSG2, tryp shut down VSG2 and express VSG3. Immune sys cannot kill them bc they will keep going like this
  • All immune sys energy is going into this mechanism, making co-infection w something else i.e. flu, worse
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

CTL/CD8 job in parasitic infection

A

Main job of CTLs when they encounter parasite is killing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

CD4 helper cells (2)

A

Th1 and Th2 are CD4 helper cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Th1

A

Th1:
- When a T cell is exposed to IL-12, it becomes Th1
- Th1 secretes IL-2 to stimulate Th (helper) and Tc (cytotoxic) proliferation, and IFN-gamma to engage with NK cells and do immune response
- Th1 cells induce cell mediated response—all immune responses are mediated by cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Th2

A

Th2:
- When T cell is exposed to IL-4, becomes Th2
- Secretes IL-4 to further Th2 response, IL-5 for eosinophil growth, and IL-10 to inhibit Th1 response
- Mediates humoral immunity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Immune response for schistosoma mansoni (worm)

A
  1. Worm into body (likely GI)
  2. Immune sys secretes IgE antibodies
  3. IgE’s tag worm
  4. IgE’s activate complement—>inflammatory molecs—>mast cell activation
  5. When mast cells are activated, they will secrete ECF and NCF (eosinophil and neutrophil)—> calls eosinophils and neutrophils to interact w IgE
  6. Systemic inflammation

**Chemotaxis is required to get to site of infection
**Mast cells main role is to interact with IgE and secrete inflammatory molecs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Ascaris nematodes

A
  • Roundworms
  • Very large
  • In GI tract—eggs hatch in gut, larvae migrate to lungs, burst out of blood into alveoli into grown worm, coughed back into gut
  • Female nematodes can release 500k eggs per day
  • Eggs can live for 15 years in host if they never burst, you can have all these eggs living in your GI tract and not know
  • Once the egg is burst is when immune sys recognizes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Onchocerca nematode

A
  • “River blindness”, can go into eye and cause blindness
  • Transmitted by black fly bite—fly is infected with egg and transmits them into human host. Eggs will burst in human into worms
  • Cause nodules below skin
  • Typically go in brain
  • type 1 immune response
17
Q

Toxocara nematode

A
  • Dog is host
  • Same life cycle as #1
  • If it infects human, it can be in brain/CNS
  • Induce type 1 inflammatory response
  • When infection is too persistent, immune sys will give up. They will form form granulomas (capsule against parasite) to ensure virus doesnt replicate, but it will never get killed
18
Q

Enterobius nematode

A
  • Very common
  • Eggs where embryo of worm is developing are infective along with the worms
  • Usually develop in LI, migrate into anus
  • Not very pathogenic
  • Limited immune response, mainly just itch
  • Treatment over the counter
  • Can live in dust for a long time waiting to infect next person
19
Q

What is VSG

A

Genes encoding for surface glycoproteins

20
Q

Immune modulation by helminths

A
  • Helminths are metozoan parasites
  • Influence activation and induce cell death in T cells
  • Steer T cells response from type-1 immune response (CD8) pathways to type-2 immune response (CD4)
  • Induce polyclonal B cell activation
  • Induce class switch to IgE—this means vaccine is inaffective bc vaccines are targeted toward IgG
21
Q

Implications of IgE on vaccine

A
  • We design vaccines to make IgG antibodies to neutralize antigens
  • With IgE, its main role is to interact with mast cells/neutrophils/basophils to induce degranulation, but not killing
  • Vaccine doesnt work very well against IgE
22
Q

What is chemotaxis?

A

When our immune cells are circulating, secretion of mediators calls them to parasite infection site
Chemotaxis: directed movement of cells to go to site of infection

23
Q

Selected important parasites

A
  • Nematodes (roundworms)
  • Cestodes (tapeworms)
  • Trematodes (flukes)
  • Extracellular Protozoa and amoeba
  • Intracellular Protozoa
24
Q

Trichinella nematode

A
  • Mostly found on uncooked pork
  • Larvae live in muscle, adults live in gut (SI)
  • Can damage immune sys, big inflammatory response can cause organ damage
  • We have limited protective immune response
  • We have medication to protect against it
25
Q

Anisakiases nematodes

A
  • Marine, often called “cod worm”
  • Caused by eating raw fish
  • Final host is seal, intermediate host is fish
  • Was an issue for indigenous ppl
  • Fish are candled to remove them
  • Red in colour
26
Q

Anisakidae nematode

A
  • Similar to Anisakiases
  • Caused by eating raw fish
  • Final host is seal, intermediate host is fish
  • Was an issue for indigenous ppl, still common in Canada
  • Clear in colour
  • Inflammatory response can lead to cancer — go into bile duct
27
Q

Taenia cestodes (tapeworms)

A
  • Usually come from pork or beef we ingest or microbiota our intestines produce
  • Can get up to 10m, can live for a long time in intestines
  • Limited immune response mediated by IgA
  • Cyst (egg form) can go into brain and degrade (make holes) in brain
28
Q

Schistosoma trematodes

A
  • Very tiny
  • Can be in many tissues, typically eggs in gut adults in liver
  • Cause liver inflammation that resembles an alcoholic’s liver
  • Good at escaping immune sys by presenting diff antigens at diff points (similar to trypanosomes)
  • No effective immunity against them bc they can travel from tissue to tissue in diff forms
  • Eggs that stay in liver can cause immunopathology (immune response against a tissue). Mediated by eosinophils (type 2 granulomas) and cytokine IL-5. Causes acute liver failure
29
Q

**Trypanosoma extracellular Protozoa

A
  • Extracellular microorganism
  • African and South American species
  • Creates “sleep sickness”, goes into the blood
  • Caused by tsetse flies
  • Non-protective CNS immunopathology: immune sys creates inflammation but doesnt protect tissues
  • Surface coat changes to evade immune attack (exact same as trypanosome eg)
30
Q

Giardia extracellular protozoa

A
  • Common in day cares in Canada
  • Feco-oral transmission
  • “beaver fever”—canada
  • Simple life cycle—ppl ingest cysts whcih develop into nerves
  • Adults live in the intestine
  • Destroy villi, patients have nutrient deficiencies bc they can’t absorb nutrients from food
  • IgA response
31
Q

Entamoeba extracellular protozoa

A
  • Large single-celled organisms
  • Can destroy RBCs
  • Host response is cell-mediated immunity
  • Adult form typically live in GI tract
    -Sometimes they go into liver which is when patients are effected severely
  • Can also go into CNS, but really is not common
  • Limited protective immunity
  • Can be fatal
32
Q

Parasite #13: Leishmania intracellular protozoa

A
  • Is becoming more common
  • Causes skin lesions
  • Common in Africa and Asia
  • Transmitted by sandfly bite
  • Can infect macrophages. They let macrophages engulf them but then attack them once inside, allowing them to be capable of immune evasion
  • When in spleen and liver are very severe and possibly fatal
33
Q

**Parasite #14: Plasmodium intracellular protozoa

A
  • AKA malaria
  • Common in LDCs
  • Transmitted by mosquitos, hard to control
  • Severe implications in all countries affected
  • Kills 3000 kids everyday, 1-3 mil ppl mostly kids every year
  • Lots of steps to life cycle, hard to develop drug/vaccine. Drug/vaccine recently was approved
  • Life cycle: infection w/ sporozoites via mosquito—>sporozoites migrate into liver, change into merozoites—>merozoites out of liver to infect and lyse RBCs—>asexually repro—> gametocytes—>transmission to mosquito
  • Most common symptom is anemia due to RBC lysis
  • Change expression so its hard for immune sys to keep up
  • Protection by sickle cell anemia trait—their RBCs have diff morphology
  • Look for “ring stage” of RBCs to confirm infection
  • Can be fatal fast
34
Q

Prevention and diagnosis of intracellular protozoa (such as malaria)

A
  • Chloroquine—malaria has resistance
  • Mefloquine—has a lot of bad side effects
  • Doxycycline, malarone
35
Q

3 main diseases that havent been cured:

A
  • HIV
  • TB
  • Malaria
36
Q

Extra cause of malaria

A
  • Ppl who survive malaria have other issues
  • Bc RBCs are killed/deformed, can trouble transporting oxygen
  • Can cause thrombosis, brain bleeding, etc

MICI 2100 (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions