Retroviridae - Gammaretrovirus: Feline Leukemia Virus and Feline Sarcoma Virus

Question 1

Which genus is responsible for Feline Leukemia Virus (FeLV)?

Answer 1

Gammaretrovirus

Question 2

True/False. FeLV is associated with only neoplastic diseases of cats.

Answer 2

False. This highly contagious virus is associated with neoplase and non-neoplastic diseases of cats.

Question 3

Which gene encodes the p27 protein of FeLV?

Answer 3

The gag gene

Question 4

Which FeLV viral protein are most seriological assays designed to detect?

Answer 4

p27 protein

(also the capsid protein)

Question 5

Which gene encodes the p15E protein of FeLV?

Answer 5

The env gene

Question 6

What role does p15E protein play in immunosuppression and facilitation of virus persistence?

Answer 6

Suppressed lymphocyte blastogenesis

Blocks the respons of T cells to IL-1 and IL-2

Suppresses the reponse to FOCMA

Question 7

Which gene encodes the gp70 protein of FeLV?

Answer 7

The env gene

Question 8

Which viral protein is responsible for attachment of virus to host cells?

Answer 8

gp70 protein

Question 9

Neutralizing antibodies against which protein offers protection against viremia?

Answer 9

gp70

Question 10

How many subgroups of FeLV are there and what are they based on?

Answer 10

Based on differences in gp70 protein, there are at least 4 different FeLV subgroups

FeLV-A

FeLV-B

FeLV-C

FeLV-T

Question 11

Which subgroup of FeLV is found in all naturally infected viremic cats and is highly contagious?

Answer 11

FeLV-A

Question 12

Which subgroup of FeLV is the only one that is horizontally transmitted from cat-to-cat?

Answer 12

FeLV-A

Question 13

True/False. Cats infected with both FeLV-A and FeLV-B have a higher risk of developing tumors than those infected with FeLV alone.

Answer 13

True.

Question 14

Which FeLV subgroup arises through recombination between FeLV-A and endogenous retroviral genome sequences contained in normal feline DNA?

Answer 14

FeLV-B

Question 15

Which FeLV subgroup causes immunosuppression and rapidly fatal non-regenerative anemia?

Answer 15

FeLV-C

Question 16

Which FeLV subgroup arises de-novo as a result of mutations and recombination in receptor binding region of the FeLV-A env gene?

Answer 16

FeLV-C

Question 17

Which FeLV subgroup is rarely described in literature and exhibits T-cell tropism associated with lymphopenia?

Answer 17

FeLV-T

Question 18

What kind of environment would you expect FeLV to survive the longest in?

Answer 18

A moist environment (24-48 hrs at room temp)

[dry environment survives only minutes]

[FeLV is extremely liable and rapidly inactivated by common disinfectants]

Question 19

True/False. A cat that is indirectly exposed to FeLV for a short amount of time will contract the virus.

Answer 19

FALSE!

Prolonged direct exposure is required for transmission.

Question 20

How is FeLV most commonly transmitted?

Answer 20

Occurs primarily through saliva (virus concentration is high)

(also by iatrogenic transmission and in-utero)

Question 21

Where does FeLV mulitply?

Answer 21

T and B lymphocytes

Question 22

Were does FeLV initially replicate after infection?

Answer 22

The local lymphoid tissue in the oropharyngeal area

Question 23

Infection of leukocytes and platelet precursors takes place where and causes what?

Answer 23

Bone marrow

This causes the subsequent release of infected cells in circulation which causes a secondary viremia

Question 24

What stage of FeLV infection do cats have high levels of neutralizing antibodies but never become viremic?

Answer 24

Abortive infection

“self limiting infection”

Question 25

Which stage of FeLV infection can cats no longer eliminate the virus from their body and becomes latent?

Answer 25

Regressive infection

Question 26

What reactivates a FeLV regressive infection?

Answer 26

Immunosuppression (stress ect)

Question 27

Which stage of FeLV infection is associated with extensive viral replication with no containment?

Answer 27

Progressive infection

Question 28

True/False. Progressively infected cats remain persistently viremic and are infectious to other cats for life.

Answer 28

True

Question 29

Which region of FeLV transactivates cancer-related signaling pathways by activating **NF kappa B**?

Answer 29

U3-LTR

Question 30

Which tumor specific antigen is present only on membranes of cells transformed by FeLV or FeSV?

Answer 30

FOCMA (feline oncornavrius-associated cell membrane antigen)

Question 31

Are cats with high levels of FOCMA antibodies resistant to development of leukemia and lymphoma regardless if the test negative or postive for FeLV?

Answer 31

Yes

Question 32

True/False. FOCMA antibody neutralizes FeLV.

Answer 32

False FOCMA antibody does not neutralize virus Cats with FOCMA antibody titers may still be viremic and die from nonmalignant disease

Question 33

Which form of lymphosarcoma is primarily seen in kittens?

Answer 33

Thymic (T cell tumor)

Question 34

Which form of lymphosarcoma is present in multiple lymphoid and non-lymphoid organs and tissues?

Answer 34

Multicentric (T cell tumor)

Question 35

Which form of lymphosarcoma is usually seen older cats and involves GALT and/or mesenteric lymphnodes?

Answer 35

Alimentary lymphosarcoma (B cell tumor) [cats are usually FeLV neg]

Question 36

Which type of myeloproliferative disease causes abnormal proliferation of erythroid cell lines?

Answer 36

Erythromyelosis

Question 37

Which type of myeloproliferative disease causes abnormal proliferation of granulocytic myeloid cells?

Answer 37

Granulocytic leukemia | (usually neutrophils)

Question 38

Which type of myeloproliferative disease causes abnormal proliferation of erythroid and granulocytic myeloid precursers?

Answer 38

Erythroleukemia

Question 39

Which type of myeloproliferative disease causes abnormal proliferation of fibroblasts and cancerous bone?

Answer 39

Myelofibrosis

Question 40

What condition is due to immune complex hypersensitivity, resulting in reactivation of latent infections and secondary bacterial infections?

Answer 40

Hypocomplementemia

Question 41

Which kind of vaccines are used agains FeLV and how much does it reduce the incidence of disease?

Answer 41

Reduces incidence of disease by 80% Inactivated vaccine Canarypox virus carrying FeLV gag and even genes Genetically engineered vaccine (gp70 subunit vx)

Question 42

Which virus arises from the recombination events between FeLV-A and host cell proto-oncogenes?

Answer 42

Feline Sarcoma Virus (FeSV)

Question 43

True/False. All strains of FeSV that cause fibrosarcomas are pseudotypes.

Answer 43

True