retro 1 Flashcards by Taylor Luskin

What enzyme does this virus family use to produce DNA intermediates from their RNA genome?

Reverse Transcriptase

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An RNA-dependant DNA polymerase that is present within the virions of all members of the family.

Reverse Transcriptase

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True or FalseRetro viruses infect a wide variety of animals and humans , can produce latent infections,and are associated with certain types of cancers.

TRUE

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RetroENVELOPED or NOT?

ENVELOPED

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Name the 3 genes that all non defective retroviruses have.

GAG- encodes virion core proteinsPOL- encodes reverse transcriptase and integraseENV- encodes the envelope proteins

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How does the virus penetrate the cell membrane?

Membrane Fusion

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Can the virus use endocytosis or exocytosis to gain entry inside the cell?

Endocytosis

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Unlike HIV, Retros do not need a co factor.True or False

FalseRetro viruses may require a co receptor like HIV

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What enzyme is used to intergrate the viral DNA into the host cellular chromosomal DNA ?

Integrase enzyme

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Maturation of virions occurs by _________ through the host cell plasma membrane.

BUDDING

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Assembly and packaging of viral protein, encapsidation or viral RNA occurs in the ___________.

Cytoplasm

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_____________ is replicated with host genome and can be passed to daughter cells resulting in transmission from one generation to the next.

PROVIRUS

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The replication of retros is accompanied by high mutation frequency that is due to the lack of _________________ by reverse transcriptase.

3’ to 5’ exonuclease proofreading mechanism

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What are non pathogenic DNA stretches found widely in genome of most vertebraes that closely resemble retros?

Endogenous retroviruses

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All RNA tumor viruses belong to the family Retroviridae.TRUE or FALSE

TRUE TRUE TRUE

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What gene does the acute transforming retroviruses carry that makes themdirectly oncogenic by having the power of unregulated expression and are under the control of viral LTRs?

v-oncRemember: c onc/proto oncogenes are host genes that encode important cell signaling porducts that regulate normal cell proliferation

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What gene does the virus loose during recombination and what gene does the virus aquire?

Looses its own ENV geneGains the host PROTO-ONCOGENENote: This makes v-onc containing viruses unable to synthesize a complete envelope, are replication defective and must associate with non defective viruses to replicateEXCEPTION: Rous sarcoma virus

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A type of Retrovirus thatdoes not contain the v-onc gene.

Slow/Chronic Transforming Retrovirus

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EtiologyBovine Leukemia(Enzootic Bovine Leukosis)

Deltaretrovirus

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What is the unique sequence inBovine Leukemia Virus that is not of host cell origin between ENV and 3’LTR?

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What is the regulatory protein that is encoded in the pX region,activates the replication of BLV and contributes to the induction of lymphoma(oncogenesis)?

Tax protein

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In what cells is the Bovine Leukemia virus mostly present?

B lymphocytesTherefore can be found in blood, milk and tumor masses.

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Name the 6modes of transmission for the Bovine Leukemia VirusRemember virus is in B lymphocytes, so how can B lymphocytes be transmitted

Blood Transfusion2. Iatrogenic3. Rectal Palpation4. Mechanically by blood sucking insects5. Vertical(in utero)6. Colostrum or milk

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What cells and what immunoglobulin are the primary target of Bovine Leukemia Virus?

B Lympohocytes that express IgM

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What 2 ways does Bovine Leukemia virus escape immune elimination?

1.By controlling viral gene expression in vivo2. Promoting cells survival by inhibiting apoptosis

Cattle with BoLA-Aw7 alleles are:resistant or susceptibleto Bovine Leukemia Virus?

BoLA-Aw7RESISTANT TO THAT SHIT!7 is God's favorite number = good= resistant

Cattle with BoLA-Aw12 alleles are:resistant or susceptible to Bovine Leukemia Virus?

BoLA-Aw12 allele SUSCEPTIBLE :( Poor Cow

Primary infection of Bovine Leukemia virus gives of what kind of clinical signs?

Asymptomatic or flu like

When can you detect the levels of antibodies after infection of Bovine Leukemia Virus?

4 to 12 weeks after exposure

In what phase of pathogenesis of BLV lasts for several months/years, the animal shows no signs, and they become latent carriers of the infection?Primary PhasePersistant InfectionPersistant LymphocytosisTumor Phase

PERSISTANT INFECTION Lucky cows to be persistantly infected but show no signs.

Persistant lymphocytosis and benign proliferation of B lymphocytes are characteristcs of what pahse of Bovine Leukemia Virus?

Persistant Lymphocytosis Morbidity, weakness and opportunistic infections

In what phase of pathogenesis does the animal infected with Bovine Leukemia begin to develop lymphosarcomas?

TUMOR PHASE Animal undergoes sudden death because of hemorrhage of the spleen.

True or False:Seropositive(persistantly infected) animals with or without persistant lymphocytosis may develop lymphosarcoma.

TRUE TRUE TRUE

What is the age range of cattle where the tumor phase of Bovine Leukemia usually observed?

4-8 years of age = Tumor Phase

Bovine Leukemia can cause lesions in which of the following areas in cattle:*More than one option*Vagina, Digestive Tract, Eye, Lymph nodes, Liver & Kidney, Lungs & Heart

Digestive Tract, Lymph Nodes, Liver & Kidney, Lungs & Heart*That includes the ABOMASUM*

An increase in the absolute number of peripheral blood circulating B-lymphocytes(above 10,000/mm).

Persistant Lymphocytosis

What 2 viral proteins will the cattle continously have antibodies against and can be detected in their serum when doing AGID test?

Major Internal(p24) and Envelope(gp51)

Identification of cattle infected with Bovine Leukemia virus can be done by using what serological test?

AGID Test

Once you identify the seropositive animals for Bovine Leukemia, what should you do IMMEDIATELY?

KILL THEM ALL Poor cows :(

After you have killed all the cattle infected with Bovine Leukemia virus, when should you retest the herd Dr. Lemoine?

30-60 days later

When there is low prevalence of Bovine Leukemia in your herd, what test should you use on the calves and doubtful cases?

PCR

"If I test the cows in your herd today and they are negative for Bovine Leukemia farmer Pete, then I will come back to your farm every ______ months for 2 years and declare your herd free of the virus "

6 months MAKE SURE YOU HAVE STRICT FARM BIOSECURITY!!!

What are the three forms of Sporadic Bovine Leukosis?

Juvenile, Thymic, and Cutaneous

Which form of Sporadic Bovine Leukosis shows enlargement of all lymph nodes and bone marrow necrosis?

Juvenile

The form of Sporadic Bovine Leukosis that shows brisket edema and jugluar vein engorgement and massive thymic enlargement is ____________.

Thymic form

This form of Sporadic Bovine Leukosis affects cattle 1-3 years old and shows cutaneous plaques and nodules on the neck, back, croup, and thighs.

Cutaneous

Etiology Feline Leukemia VIrus (FeLV)

Gammaretrovirus

What protein involved in FeLV ,is encoded by the gag gene and is the major FeLV group specific antigen?

p27 protein

___________forms the primary structural proteins of the core of the feline leukemia virus.

Capsid Protein (p27)encoded by gagmajor FeLV group specific antigen

Most serological assays for FeLV are designed to detect what protein?

p27 protein

p27 protein is found in the _________ of the infected cells and in the ________ form in blood, tears and saliva.

cytoplasm; free

What protein associated with FeLV is encoded by env gene, is a transmembrane protein, plays a role in immunosuppression and facilitates virus persistance?

p15E protein

p15E protein plays a role in immunosuppression by _____________ lymphocyte blastogenesis, ___________the response of T cells to IL1 & IL2 and by _________the response to FOMCA.

suppressing; blocks; supressing

What protein involved in FeLV is also encoded by the env gene but is responsible for the attachment of the virus to the host cell?

gp70 protein"Yo G come over here and attach to me before I turn 70"

True/FalseNeutralizing antibodies against gp70 protein does not offer protection against viremia.

FALSENeutralizing antibodies against gp70 protein DOES affer protection against viremia.

Antibodies are subgroup specific, so it is important to know the subgroups of FeLV. Name the 4 subgroups.

FeLV AFeLV BFeLV CFeLV T

What is the only subgroup in FeLV that is horizontally transmitted from cat to cat?

FeLV- AFound in all naturally infected viremic cats and is hgihly contagious

What subgroup is only found in 50% of naturally infected cats with FeLV-A ?

FeLV- B

True or FalseCats infected with both FeLV A and FeLV B have a higher risk of developing tumors than those infected with FeLV A alone.

TRUE!!!!

Which FeLV subgroup is rare and arises from mutations in receptor binding region of FeLV A env gene?

FeLV-C

Which FeLV subgroup causes immosuppression and rapidly fatal non regenerative anemia?

FeLV-C

Which FeLV subtype evolved from FeLV-A and exhibits T cell tropism associated with lymphopenia?

FeLV-T

Does FeLV survive longer in a moist or dry enviroment?

MOIST! Can survive in moist enviroment at room temperature for 24-28 hours.In a dry enviroment the virus is inactivated in 3-5 minutes.

FeLV is an extremely stable or liable virus and can or cannot be inactivated by common disinfectants.

FeLV is an extremely liable virus and can be inactivated by common disinfectants.

Transmission of FeLV occurs primarily through which route?

SALIVA!Vius concentration is very high in saliva. Infected mom licks and nurses kitty cats.

In what cells does FeLV multiple?

T and B lymphocytes

When FeLV spreads to the spleen, lymphnodes, intestines and bone marrow can can be sure to see a positive result in which test?

ELISA

Which test will show a positive result for FeLV when the leukocytes and platelet precursors are infected?

IFA test

There are four stages of infection with FeLV. Which stage stops replication because the cat has high levels of neutralizing antibodies allowing the cat to never become viremic?

ABORTIVE INFECTIONFeLV antigen nor viral RNA or proviral DNA can be detected in the blood at anytime.

In which stage of infection is replication and viremia contained after bone marrow infection?

RegressiveCannot get rid of virus now because it is in the bone marrow stem cell DNA= latent infection

True or FalseRegressive Infection can be reactivated by immunosuppression.

I concur

The stage of infection that does not get contained, there is extensive virus replication and the cants remain persistently viremic and are infectious to other cats for the remainder of their life.

Progressive Infection

A rare form on FeLV infection that is characterized by persistent atypical local viral replication, in the mammary gland, bladder and eyes.

Focal or Atypical Infection

How FeLV causes cancer:a. insertion of the genome into the host's genome near myc gene, causing activation and overexpression of that geneb. By forming recombinant virus containing cellular oncogene sequences that are then rearranged and activatedc. The U3-LTR region of FeLV transactivated cancer related signaling pathways by activating NY kappaBd. ALL OF THE ABOVE

ALL of the above !

What does FOCMA stand for?

Feline oncornavirus associated cell membrane antigen

A tumor specific antigen present only on membrane of cells transformed by FeLV or FeSV.

FOCMA

Antibodies against FOCMA mediate ________ of tumor cells by ADCC and complement acitvation.

Lysis

True or FalseCats with high levels of FOCMA antibodies are resistant to development of leukemia and lymphoma reguardless if they test postive or negative for FeLV.

I concur.

True or FalseFOCMA antibdy neutralizes FeLV.

FALSEFOCMA antibody does NOT neutralize the virus. They may still be malignant and die from non malignant disease.

The majority of cats:a.do not develop neutralizing and FOCMA antibodiesb.do not develop FeLV related diease BUT proviral DNA and malignancy can occur in the future. c.have latent infections with no virema

B. 92-96% of cats have a self limiting infection where they DO develop neutralizing and FOCMA antibodies and do not develop FeLV related disease.

The persistant active infection of FeLV lacks ___________ and ___________. Immunosuppression is most common sequel and accounts for most deaths.

FOCMA and Neutralizing Antibodies