Term
| What do all retroviruses contain? |
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Definition
| RNA dependent DNA polymerase (reverse transcriptase) |
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Term
| What genes make up the retrovirus proteins? |
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Definition
| Core proteins are coded for by gag, enzymes by pot, and the envelope by env |
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Term
| What are acute transforming viruses? |
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Definition
| They pick up an oncogene during replication and replace pot |
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Term
| Why is rous sarcomavirus special? |
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Definition
| It adds src without replacing necessary genes |
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Term
| What are endogenous retroviruses? |
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Definition
| Viruses transmitted down a germ line with inducible expression. The genome is complete and replication is productive. No transformation or oncogenesis |
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Term
| What are exogenous retroviruses? |
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Definition
| They have horizontal transmission. Those with complete genomes are not oncogenic, but defective ones that require helpers are highly oncogenic |
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Term
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Definition
| A human oncovirus, a leukemia virus that affects T-cells. It contains regulatory genes near the env gene |
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Term
| What are some outcomes of human oncoviruses? |
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Definition
| Adult T-cell lymphomic leukemia (ATLL)or an associated myelopathy termed tropical spastic paraparesis, which is not oncogenic |
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Term
| What accessory genes are encoded by HIV? |
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Definition
| HIV is a diploid lentivirus encoding nef (mediates aggressiveness), vif (infectivity), vpr (transport to nucleus), and vpu (viral release) |
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Term
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Definition
| A sugar cluster on the HIV membrane that binds to CD4 then to CXCR4, allowing gp41 to fuse the envelope with the cell |
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Term
| What is the R5 strain of HIV? |
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Definition
| It infects macrophages and CD4 T-cells by binding to CCR5 on cell surfaces |
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Term
| How are some people immune to AIDS following HIV exposure? |
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Definition
| Lack of CCR5 or CXCR4 receptors prevent infection by HIV |
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Term
| What happens after HIV binds to a host cell? |
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Definition
| +RNA is reverse transcribed to dsDNA, which goes to the nucleus and integrates into the host genome at random. HIV proteins are cleaved with a protease and associate with 2 RNA genomes as new virions |
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Term
| What is the result of infection of TH1 and TH2 cells with HIV? |
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Definition
TH1: affects CD8 CTL-cell activation
TH2: slow antibody production |
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Term
| What causes the chronic diarrhea and weight loss associated with HIV? |
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Definition
| Intestinal epithelial infection |
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Term
| Where do HIV particles aggregate? |
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Definition
| In the germinal centers of lymph nodes, where B-cells mature. |
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Term
| What is a result of HIV infection of follicular dendritic cells? |
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Definition
| Formation of HIV immune complexes |
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Term
| What are causes of cellular destruction? |
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Definition
| Viral lysis, formation of multinucleated giant cells by fusion proteins, or activation of antibody-mediated cytotoxicity via ininfected CD4 T-cells binding free gp120 |
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Term
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Definition
| Antigenic drift and glycosylation due to reverse transcriptase's lack of proofreading. Antibody detection is evaded |
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Term
| What is the role of macrophages in HIV infection? |
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Definition
| They are the first infected cells and are important for viral reservoir and transportation. They can spread the virus to the brain, lungs, or skin |
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Term
| What is a result of viral spread from lymph nodes? |
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Definition
| It begets loss of T cell function and opportunity for infections |
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Term
| How long does acute infection last? |
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Definition
| About two years, until anti-HIV antibodies become prevalent |
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Term
| What happens as the T-cell count drops? |
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Definition
| Antibody levels also drop and viral levels rise, leading to AIDS and dementia |
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Term
| What is systemic immune dysfunction? |
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Definition
| It begins when CD4 count is 200-400 and is exacerbated at <200 because it leads to death by opportunistic infection |
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Term
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Definition
| Via ELISA from serum followed by a Western blot or immunofluorescence. PCR and branched-chain DNA can quantify viral levels. The p24 antigen is an early marker |
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