Retroviridae - Gammaretrovirus: Feline Leukemia Virus and Feline Sarcoma Virus Flashcards
Which genus is responsible for Feline Leukemia Virus (FeLV)?
Gammaretrovirus
True/False. FeLV is associated with only neoplastic diseases of cats.
False. This highly contagious virus is associated with neoplase and non-neoplastic diseases of cats.
Which gene encodes the p27 protein of FeLV?
The gag gene
Which FeLV viral protein are most seriological assays designed to detect?
p27 protein
(also the capsid protein)
Which gene encodes the p15E protein of FeLV?
The env gene
What role does p15E protein play in immunosuppression and facilitation of virus persistence?
Suppressed lymphocyte blastogenesis
Blocks the respons of T cells to IL-1 and IL-2
Suppresses the reponse to FOCMA
Which gene encodes the gp70 protein of FeLV?
The env gene
Which viral protein is responsible for attachment of virus to host cells?
gp70 protein
Neutralizing antibodies against which protein offers protection against viremia?
gp70
How many subgroups of FeLV are there and what are they based on?
Based on differences in gp70 protein, there are at least 4 different FeLV subgroups
FeLV-A
FeLV-B
FeLV-C
FeLV-T
Which subgroup of FeLV is found in all naturally infected viremic cats and is highly contagious?
FeLV-A
Which subgroup of FeLV is the only one that is horizontally transmitted from cat-to-cat?
FeLV-A
True/False. Cats infected with both FeLV-A and FeLV-B have a higher risk of developing tumors than those infected with FeLV alone.
True.
Which FeLV subgroup arises through recombination between FeLV-A and endogenous retroviral genome sequences contained in normal feline DNA?
FeLV-B
Which FeLV subgroup causes immunosuppression and rapidly fatal non-regenerative anemia?
FeLV-C
Which FeLV subgroup arises de-novo as a result of mutations and recombination in receptor binding region of the FeLV-A env gene?
FeLV-C
Which FeLV subgroup is rarely described in literature and exhibits T-cell tropism associated with lymphopenia?
FeLV-T
What kind of environment would you expect FeLV to survive the longest in?
A moist environment (24-48 hrs at room temp)
[dry environment survives only minutes]
[FeLV is extremely liable and rapidly inactivated by common disinfectants]
True/False. A cat that is indirectly exposed to FeLV for a short amount of time will contract the virus.
FALSE!
Prolonged direct exposure is required for transmission.
How is FeLV most commonly transmitted?
Occurs primarily through saliva (virus concentration is high)
(also by iatrogenic transmission and in-utero)
Where does FeLV mulitply?
T and B lymphocytes
Were does FeLV initially replicate after infection?
The local lymphoid tissue in the oropharyngeal area
Infection of leukocytes and platelet precursors takes place where and causes what?
Bone marrow
This causes the subsequent release of infected cells in circulation which causes a secondary viremia
What stage of FeLV infection do cats have high levels of neutralizing antibodies but never become viremic?
Abortive infection
“self limiting infection”
Which stage of FeLV infection can cats no longer eliminate the virus from their body and becomes latent?
Regressive infection
What reactivates a FeLV regressive infection?
Immunosuppression (stress ect)
Which stage of FeLV infection is associated with extensive viral replication with no containment?
Progressive infection
True/False. Progressively infected cats remain persistently viremic and are infectious to other cats for life.
True
Which region of FeLV transactivates cancer-related signaling pathways by activating NF kappa B?
U3-LTR
Which tumor specific antigen is present only on membranes of cells transformed by FeLV or FeSV?
FOCMA (feline oncornavrius-associated cell membrane antigen)
Are cats with high levels of FOCMA antibodies resistant to development of leukemia and lymphoma regardless if the test negative or postive for FeLV?
Yes
True/False. FOCMA antibody neutralizes FeLV.
False
FOCMA antibody does not neutralize virus
Cats with FOCMA antibody titers may still be viremic and die from nonmalignant disease
Which form of lymphosarcoma is primarily seen in kittens?
Thymic (T cell tumor)
Which form of lymphosarcoma is present in multiple lymphoid and non-lymphoid organs and tissues?
Multicentric (T cell tumor)
Which form of lymphosarcoma is usually seen older cats and involves GALT and/or mesenteric lymphnodes?
Alimentary lymphosarcoma (B cell tumor)
[cats are usually FeLV neg]
Which type of myeloproliferative disease causes abnormal proliferation of erythroid cell lines?
Erythromyelosis
Which type of myeloproliferative disease causes abnormal proliferation of granulocytic myeloid cells?
Granulocytic leukemia
(usually neutrophils)
Which type of myeloproliferative disease causes abnormal proliferation of erythroid and granulocytic myeloid precursers?
Erythroleukemia
Which type of myeloproliferative disease causes abnormal proliferation of fibroblasts and cancerous bone?
Myelofibrosis
What condition is due to immune complex hypersensitivity, resulting in reactivation of latent infections and secondary bacterial infections?
Hypocomplementemia
Which kind of vaccines are used agains FeLV and how much does it reduce the incidence of disease?
Reduces incidence of disease by 80%
Inactivated vaccine
Canarypox virus carrying FeLV gag and even genes
Genetically engineered vaccine (gp70 subunit vx)
Which virus arises from the recombination events between FeLV-A and host cell proto-oncogenes?
Feline Sarcoma Virus (FeSV)
True/False. All strains of FeSV that cause fibrosarcomas are pseudotypes.
True
