Final; Retroviruses, AIDS, and Tumor Viruses Flashcards by Courtney Kast

Who are the members of the 4H risk group for HIV/AIDS

homosexual men
heroine addicts
Haitians
hemophiliacs

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How many types of HIV are there

HIV-1

HIV-2

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Where does HIV seem to originate from

the simian virus from Africa

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Which type of HIV is mostly a heterosexual disease

HIV-2

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This a large and diverse group of viruses with a unique replication cycle

retroviruses

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In which genre of animals are retroviruses ubiquitous, albeit benign and causing little to no impact

vertebrates

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This retrovirus does not cause disease in humans but makes foamy structures inside the cell

spumaviruses

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What are the two subfamilies of retroviridae

orthoretroviridae

spumaviridae

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What is the genome of the retroviridae

+ssRNA, diploid identical copies

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What is the virion of the retroviridae

enveloped

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What special proteins do the retroviridae contain

reverse transcriptase
integrase
protease

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What were retroviruses historically characterized by

nucleocapsid structure and location of the particle

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What are retroviruses now characterized by

genome contents; either simple or complex

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What are the genes that simple retroviruses encode

gag, pro, pol, and env genes

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What is the replication cycle of retroviruses

attachment
entry
reverse transcription
integration
transcription
translation
assembly
release
matuation

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This converts viral ssRNA to dsDNA

reverse transcriptase

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This puts the viral dsDNA into the host genome making a provirus

integrase (integration)

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This is the defining feature of a retrovirus

reverse transcription

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Reverse transcription initiates when

once the nucleocapsid is in the cytoplasm

needs higher levels of NTPs (nucleoside triphosphate)

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Where does reverse transcription occur

within a large complex similar to the nucleocapsid

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Reverse transcription is this between genome copies

promiscuous

many different recombinations when different genomes are in the virion

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What must take place in order for integration to occur

it must have access to the nucleus during mitosis

although it can also infect non-dividing cell via importation (mechanism unknown)

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How is the viral genome integrated into the host genome

3’ end processing of dsDNA
attack target DNA, nick created
host repair

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True or False

Integration is permanent, there is no mechanism to remove it

True

If integrated into the germ-line, then provirus is inherited and is called what

endogenous

Which type of integration is identified as oncogenes

transcription factor secreted growth factors growth factor receptors cell signal transduction pathway

True or False | There are many defective viruses made during replication

True

What constitutes a defective virus

missing at least one of gag, pol, or env

In order to make progeny of a defective virus, what must happen

a complementary infection with a virus that is not missing the defective gene

Many retrovirus infections are what

benign and usually not cytopathic with little impact to cell replication and physiology

Chronic infections of retroviruses cause what

they exert a small demand on cell and host resources but do cause viremia (virus in blood) and elicit an immune response

True or False | Viruses are never eliminated by the host response

True

In this type of retrovirus, the effect is like high-level mutagenesis and eventually results in tumoriogenesis

slow retrovirus

In this type of retrovirus, the majority carry cytopathic genes and directly cause tissue damage

cytopathic retrovirus

In this type of retrovirus, it induces rapid tumor formation, caries host genes (mitogenic or antiapoptotic) and is often replication defective because host gene replaces an essential gene

acute transforming viruses

What are the four distance types of Human T Cell Leukemia virus (HTLV)

1, 2, 3, and 4 | HTLV-1 associated with humans

What type of retrovirus is HTLV-1

deltaretrovirus

How is HTLV-1 transmitted

person to person; breastfeeding sharing needles sexual transmission (less efficient)

How is HTLV-1 transmitted within the host

highly cell associated | primary contact between infected and naive cells

What diseases can result from HTLV-1

adult T cell lymphoma/leukemia (ATLL); occurs in 2-4% of cases HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP); occurs in 1-2% of cases

How long is the incubation of ATLL

30-50 years

What cells does ATLL infect (HTLV-1)

memory T cells antigen activators trigger transcription of provirus, viral tax protein stimulates cell proliferation, the cell transform forming tumors with out without viral protein expression

How are ATLL and HAM/TSP transmitted

ATLL; mucosal infection | HAM/TSP; transfusion

What cells does HAM/TSP infect

infected T cells enter the CNS activating astrocytes and microglial cells recruiting inflammatory cells which cause further damage

What are the symptoms of HAM/TSP

onset 3 years after infection starts with bladder control issues progressing to lower back pain, leg weakness, or stiffness in hips/knees men will suffer impotence or erectile dysfunction

What is used to prevent HTLV-1

eliminate breastfeeding for positive people | increased screening for blood products

What is used to treat ATLL

treat the lymphoma/leukemia with chemo

What is used to treat HAM/TSP

corticosteriods | interferon yields temporary relief of symptoms

What family is HIV apart of

lentivirus | two types of HIV, 1 and 2

How was HIV identified

due to immune deficiencies occurring in previously healthy young gay men

Where is the highest prevalence of HIV

in sub-sarahan Africa

How is HIV transmitted

sexual transmission; male to male is highest parenteral; transfusion, needle sharing mother to infant

What is the latent period of HIV

6 months to 25 years

In what part of the body does the HIV infection start

infection begins virus containing blood/body fluid to mucosal membrane targets CD4+ cells initial acute infection usually 2 weeks after exposure

What are the symptoms indicative of an HIV infection

mucocutaenous ulceration and weight loss | GALT seeded as a result of acute infection (reservoir)

What happens as HIV established a chronic infection

ongoing viral replication and T cell depletion

What results as a chronic HIV infection

opportunistic infections increase | wasting

What are the prevention strategies regarding HIV

sexual behavior and protection | blood screening

What are the treatments for HIV

no vaccine | antivirals; AZT is a reverse transcriptase inhibitor