Mechanisms of Microbial Infections Part II

Question 1

Difference between susceptible and permissive cells?

Answer 1

Susceptible cells can be infected, permissive cells can be infected and allow replication (usually die)

Question 2

What’s a DNA vrus that does not replicate in the nucleus?

Answer 2

Poxvirus

Question 3

What’s an RNA virus that does not replicate in the cytoplasm?

Answer 3

Orthomyxovirus (influenza)

Question 4

Viruses that infect target cell through apical membrane? Basolateral membrane?

Answer 4

Influenza, IBR; Parvovirus

Question 5

What toxin is secreted by rotavirus? What does it cause?

Answer 5

NSP4 toxin; indirect cytotoxicity

Question 6

What type of mutation usually causes antigenic drift?

Answer 6

Missense

Question 7

What kind of viruses can recombine? Reassort?

Answer 7

DNA and RNA viruses; only segmented RNA viruses

Question 8

Most important host defense mechanisms against viruses (2)?

Answer 8

Cell-mediated immunity
Interferons- inhibit translation of virus

Question 9

How do interferons work?

Answer 9

Stimulate synthesis of proteins that block virus attachment, entry, etc.
Stimulate genome to undergo apoptosis
Activate immune cells

Question 10

What phase of cell cycle does parvovirus target?

Answer 10

S phase

Question 11

Parvo receptor in cats? Dogs?

Answer 11

Transferrin receptor and neuraminic acid
Transferrin receptor

Question 12

Alphaherpesvirus ligands and receptors; where does it enter the cell?

Answer 12

Ligands: Envelope glycoproteins B, C, D
Receptors: Herpesvirus entry mediator A, nectin 1 and 2, 3-O sulfated heparan sulfate; apical surface

Question 13

What type of cells are targeted by Malignant Catarrhal Fever?

Answer 13

CD8+ T cells

Question 14

Coronavirus ligands and receptors; where does it enter the cell?

Answer 14

Ligands: Envelope S (spike) protein
Receptors: Sialic acid, Aminopeptidase N
Apical surface of villous enterocytes

Question 15

Mutated coronavirus ligands and receptors; cell target?

Answer 15

Ligands: Envelope S1 and S2 proteins
Receptors: Feline aminopeptidase N on monocytes/macrophages

Question 16

Rotavirus ligands? Where does it enter the cell? Exotoxin produced

Answer 16

Ligands: Capsid VP4, VP7
Apical surface of enterocytes
NSP4 enterotoxin

Question 17

Aphthovirus (FMD) ligands and receptor?

Answer 17

Capsid VP1-4
Alpha integrins

Question 18

Bovine pestivirus (BVD, mucosal disease) ligands and receptors?

Answer 18

Envelope E1 and E2 glycoproteins
CD46

Question 19

Swine pestivirus (classical swine fever, hog cholera) ligands and receptors

Answer 19

Envelope Erns and E2 glycoproteins
GAGs on heparan sulfate

Question 20

Canine distemper (morbillivirus) ligands and receptors; how do they form syncytia?

Answer 20

Ligands: Envelope hemagglutinin and fusion glycoproteins
Receptors: CD150 (SLAM) on lymphocytes, Nectin-4 on epithelium; Fusion protein bind CD9 transmembrane protein on host

Question 21

Different features of rinderpest?

Answer 21

GI mostly
Form syncytia in crypts of GI
Targets basolateral surface of enterocytes

Question 22

Influenza (orthomyxovirus) ligands and receptors? Other feature

Answer 22

Envelope hemagglutinin for entry, neuraminidase for shedding
Host receptor: Sialic acid
Neuraminidase destroys glycoprotein decoy receptors in mucus

Question 23

Bovine respiratory syncytial virus (pneumovirus) ligands and receptors

Answer 23

Envelope glycoprotein G for attachment, F for fusion
Host receptor: GAGs

Question 24

Virulence factor of African Horse Sickness (reovirus)

Answer 24

NS3- protein inserted in host cell membrane

Question 25

Rabies (lyssavirus) ligand and receptor

Answer 25

Envelope G protein Neurotransmitter receptors

Question 26

Small ruminant lentivirus receptor (OPP/Maedi Visna, CAE) and pathogenesis

Answer 26

SRLV receptors A and B; infects monocytes, replicates once enters tissue and matures, so you get granulomatous inflammation

Question 27

Equine infectious Anemia (lentivirus) ligands and receptor; pathogenesis

Answer 27

Envelope gp120, gp90 Equine lentivirus receptor-1 Infects monocytes and macrophages, causes type II hypersensitivity with hemolysis (virus forms haptens on RBCs)

Question 28

Enzootic bovine lymphoma (retrovirus) ligands and oncogenesis mechanism

Answer 28

Envelope gp51, gp30 Gene transactivation- expresses BLV tax protein (p34tax) to stimulate proliferation of infected B cells

Question 29

Feline leukemia virus ligands and three types and differences

Answer 29

Surface glycoprotein and transmembrane protein FeLV A- transmissible FeLV B- arises through recombination (antigenic shift) FeLV C- arises through antigenic drift

Question 30

Toxoplasma gondii ligands and host receptors; what does it produce?

Answer 30

SAGs Laminin, lectin IL-10 and TGF beta

Question 31

What is the normal prion? The abnormal prion?

Answer 31

PrPc PrPSc

Question 32

How do prions get to their target location?

Answer 32

M cells, Peyer's patches Lymphoid spread via FDCs to nerves Retrograde axonal transport

Question 33

How does PrPSc cause disease?

Answer 33

Converts PrPc to beta sheet rich insoluble form, does not cause inflammation