Immunity to Parasites (17)

Question 1

What is the consistent feature of all parasite infections?

Answer 1

they block or delay host defenses so they can survive for sufficient time to reproduce

Question 2

What is species resistance?

Answer 2

resistance to certain diseases to which other species are susceptible

Question 3

____ is very host specific and site specific

Answer 3

Lice

Question 4

_______ and people have antigens that are closely related and share many parasites

Answer 4

Pigs

Question 5

How do parasites get past barriers?

Answer 5

physical, mechanical, chemical
penetrate skin, go into cracks on skin, hair follicles
get trapped in skin
blood-sucking arthropod vector
poor/compromised immune systems
chitin skeleton - body parts

Question 6

What are the partners-in-crime to aid passage in a host?

Answer 6

blood-sucking arthropod vectors

Question 7

Blood-sucking arthropod vectors have _______ to cross layers of skin and enter tissues below

Answer 7

specialized mouthparts; now considered a parasite

Question 8

What is a lysozyme?

Answer 8

powerful enzyme in the eye
causes conjunctivitis by mechanical irritation

Question 9

T/F: Some types of worms survive passage through the stomach. A thick cuticle of nematode protects from enzymes and acids

Answer 9

TRUE

Question 10

Explain why the tsetse fly parasite (trypanosome) evades an immune response?

Answer 10

repeated antigenic variation by the parasite
parasites express a new surface glycoprotein antigen = variant surface antigen VSG
system figures it out but made a new antigen

Question 11

What is VSG?

Answer 11

variant-surface antigen - parasites express a new surface glycoprotein antigen

Question 12

Helminths are called

Answer 12

worms

Question 13

What are innate factors of host origin that influence helminth burdens?

Answer 13

include age, sex, and GENETIC BACKGROUND
pregnancy, neonate, geriatric
selective breeding for resistance

Question 14

What is the major adaptive defense against gastrointestinal helminths?

Answer 14

type 2 adaptive immune response
antibody production of IgE
eosinophils and basophils
resembles a type 1 hypersensitivity/allerguc response

Question 15

How do you know you have worms?

Answer 15

TH2 helper cells produce: IL-4 and IL-13 to activate B cells to produce IgE, degranulation of mast cells
Produce IL-5: degranulation of eosinophils

Question 16

What are “tuft cells”?

Answer 16

have a small tuft of microvilli that extends into the intestinal lumen
play a key role initiating type 2 immune response to helminths

Question 17

What do tuft cells produce to the response of a helminth?

Answer 17

produce large amounts of IL-25, a cytokine that recruits eosinophils
activates Th2 cells and ILC2 cells

Question 18

What does IL-25 promote regarding helminths?

Answer 18

promotes hyperplasia of tuft cells
mucus-producing goblet cells

Question 19

What does IL-13 and IL-4 do when acted together to battle helminths?

Answer 19

increase gut motility and mucos production

Question 20

What is the weep and sweep phenomenon in sheep? It = _______

Answer 20

combination of increased motility with increased mucus production can expel many helminth parasites
self cure

Question 21

T/F: mammals eventually develop limited immunity to tissue helminths after several months

Answer 21

TRUE

Question 22

What did they find in resistant sheep regarding MHC?

Answer 22

found that resistant sheep have MHC-linked genes that exert a signifiant influence on levels of resistance
ability to turn on naive T-cells
found they have accumulation of mucosal mast cells and eosinophils in the GI tract
mechanism driven by activated T-lymphocytes (secrete IL-4 and IL-5)

Question 23

What is the most important vector of disease agents in domestic and wild animal species, second to mosquitoes as transmitters?

Answer 23

ticks

Question 24

Ticks have a ______ that attaches the tick firmly to the host and seals the area around the hypos tome. Seal out moisture and recycle water back from blood and returned to host

Answer 24

cement protein

Question 25

Tick saliva contains _______ that assist the parasite in obtaining its blood meal

Answer 25

digestive enzymes

Question 26

The saliva in ticks have these features

Answer 26

anticoagulation
antihistamine
antiplatele
vasodilators

Question 27

What are master evaders?

Answer 27

block of delay host defenses so that they may survive for sufficient time to reproduce

Question 28

Intracellular _______ are very good at hiding inside cells, even macrophages

Answer 28

protozoa

Question 29

The extracellular protozoan parasite, _______, can change its coat to evade the immune system

Answer 29

trypanosoma

Question 30

Adaptive immune responses to helminths involves switching immunoglobulin class expression to _____ and activating _____ and _____ to release granules to pinch holes in the worm’s cuticle

Answer 30

IgE
mast cells
eosinophils

Question 31

Genetic resistance to ______ in merino sheep is due to ______ genes that allow them to illicit a strong [Th1/Th2] response that expels worms from the gut

Answer 31

haemonchus
MHC-linked genes
Th2

Question 32

Tick saliva has _______ chemicals that suppress the immune system

Answer 32

immune-modulating