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60 Cards in this Set
- Front
- Back
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What are the 3 major genes of the HIV RNA genome?
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1.-gag gene- codes for core and matrix genes
2.- pol gene-codes for reverse transcriptase, protease, integrase and ribonuclease 3.-env gene-codes for membrane and surface proteins |
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What does the U5 sequence signify?
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this is a unique sequence which contains part of the site required for viral integration into the host cell chromosome.
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What does the nucleotide sequence U3 signify?
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At the 3 end of the viral RNA, U3 has sequences that are important in the control of transcription of the DNA provirus.
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What is involved regarding attachment to a specific cell surface receptor?
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It is accomplished via the SU fragment of the env gene, which binds to a CD4 molecule.
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What type of cells does the virus infect?
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T cells, lymphocytes, monocytes, and dendritic cells which contain this protein in their membranes.
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Regarding entry of this virus into the cell, are any additional coreceptors involved?
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Yes, a chemokine receptor is required for entry of the viral core into the cell. Binding to a coreceptor activates the viral TM(fusion) glycoprotein.
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What is a chemokine?
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It is a cytokine with chemotactic properties produced by lymphocytes and macrophages. These cells express different chemokine receptors.
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After entering the host cell, is the HIV-RNA immediately translated?
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No, it is transcribed into DNA by reverse transcriptase, which is an RNA directed DNA polymerase.
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What does the viral reverse transcriptase first synthesize?
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It synthesizes a DNA-RNA hybrid molecule, then its RNase activity degrades the parental RNA molecule while making the 2nd strand of DNA.
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Regarding integration of the provirus, where is the provirus taken?
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It is transported to the nucleus with the aid of MA(matrix protein) At this point viral integrase cleaves the chromosomal DNA and covalently inserts the provirus, which is now a stable component of the genome.
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What are the two genomic forms at this juncture?
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There is a ssRNA present in the extracellular virus, and proviral dsDNA within the cell.
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After transcription and translation of integrated viral DNA sequences, what happens to the provirus?
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It is transcribed into a full length mRNA by the cell RNA polymerase 2.
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What are three functions of the genome length mRNA?
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1-Some copies will be the genomes of progeny virus and transported to the cytoplasm
2.- some are translated to produce the virion gag proteins. 3.- other copies of viral RNA are spliced creating new translatable sequences. |
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Regarding assembly and maturation, what becomes of the env polyprotein?
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It is processed and transported to the plasma membrane through the golgi and cleaved by a host cell protease.
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What happens as the virion buds from the host cell surface?
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Viral protease is activated and cleaves the polyproteins into component proteins which subsequently assemble into mature virions.
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Can a HIV infected woman transmit the disease to her newborn?
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She has a 15-40 % chance of transmitting the infection to her newborn, either transplacentally or via breast feeding.
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What is the timeline regarding AIDS progression?
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The progression from HIV infection to AIDS develops in 50% of HIV infected individuals in an average of ten years. There are several phases of progression.
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What is the course of the initial infection?
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Initially infected cells are macrophages within the genital tract, it then disseminates via the blood and localize in dendritic cells. It may then infect CD4+ lymphocytes moving through the germinal centers of lymph nodes. This creates a reservoir of chronically infected cells.
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Can a HIV infected woman transmit the disease to her newborn?
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She has a 15-40 % chance of transmitting the infection to her newborn, either transplacentally or via breast feeding.
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What is the timeline regarding AIDS progression?
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The progression from HIV infection to AIDS develops in 50% of HIV infected individuals in an average of ten years. There are several phases of progression.
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What is the phase of acute viremia?
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Several weeks after the initial infection, 1-2 thirds of patients experience an acute disease syndrome. There is a high level of virus replication in CD4+ cells. large amounts of capsid protein(CA antigen) are present in the blood.
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How soon do circulating antibodies appear after initial infection?
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Circulating A/Bs appear in 1-10 weeks after initial infection. (seroconversion)
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Can a HIV infected woman transmit the disease to her newborn?
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She has a 15-40 % chance of transmitting the infection to her newborn, either transplacentally or via breast feeding.
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What is the course of the initial infection?
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Initially infected cells are macrophages within the genital tract, it then disseminates via the blood and localize in dendritic cells. It may then infect CD4+ lymphocytes moving through the germinal centers of lymph nodes. This creates a reservoir of chronically infected cells.
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What is the phase of acute viremia?
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Several weeks after the initial infection, 1-2 thirds of patients experience an acute disease syndrome. There is a high level of virus replication in CD4+ cells. large amounts of capsid protein(CA antigen) are present in the blood.
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What is the latent period?
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The acute phase viremia is reduced eventually with the appearance of a HIV specific cytotoxic T-lymphocyte response. A latent period lasting from months to many years follows the acute infection.
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How soon do circulating antibodies appear after initial infection?
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Circulating A/Bs appear in 1-10 weeks after initial infection. (seroconversion)
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What is the timeline regarding AIDS progression?
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The progression from HIV infection to AIDS develops in 50% of HIV infected individuals in an average of ten years. There are several phases of progression.
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What is happening to the provirus during the latent period.
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App 90% of HIV proviruses are transcriptionally silent, so only 10% of the cells containing HIV DNA also contain viral mRNA of viral proteins. The CD4+ count is declining slowly.
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What is the latent period?
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The acute phase viremia is reduced eventually with the appearance of a HIV specific cytotoxic T-lymphocyte response. A latent period lasting from months to many years follows the acute infection.
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What is the course of the initial infection?
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Initially infected cells are macrophages within the genital tract, it then disseminates via the blood and localize in dendritic cells. It may then infect CD4+ lymphocytes moving through the germinal centers of lymph nodes. This creates a reservoir of chronically infected cells.
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How many virions and CD4 T cells are produced each day?
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It is estimated that app 10(11) virions and 10(9) CD4 T cells are produced daily.
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What is happening to the provirus during the latent period.
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App 90% of HIV proviruses are transcriptionally silent, so only 10% of the cells containing HIV DNA also contain viral mRNA of viral proteins. The CD4+ count is declining slowly.
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What is the phase of acute viremia?
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Several weeks after the initial infection, 1-2 thirds of patients experience an acute disease syndrome. There is a high level of virus replication in CD4+ cells. large amounts of capsid protein(CA antigen) are present in the blood.
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What are some clinical complications of HIV during the latent phase?
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Lymphadenopathy, diarrhea, chronic fevers, night sweats and weight loss. Opportunistic infections such as candidiasis and herpes zoster may periodically occur.
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How many virions and CD4 T cells are produced each day?
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It is estimated that app 10(11) virions and 10(9) CD4 T cells are produced daily.
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How soon do circulating antibodies appear after initial infection?
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Circulating A/Bs appear in 1-10 weeks after initial infection. (seroconversion)
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What are some clinical complications of HIV during the latent phase?
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Lymphadenopathy, diarrhea, chronic fevers, night sweats and weight loss. Opportunistic infections such as candidiasis and herpes zoster may periodically occur.
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Is progression to AIDS a sudden event.
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It is not, but occurrs as a continuum of clinical states. Coinfection with herpes type 6 can transactivate transcription from the silent HIV provirus, increasing HIV replication. T cell precursors are killed, and the capacity to generate CD4+ cells is gradually lost. HIV mutants with altered antigencity appear which are not recognized by the existing humoral A/B or cytotoxic T cell lymphocytes.
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When is the patient considered to acually have AIDS?
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When the CD4 count falls below 200/ml with the appearance of concurrent disease patterns and opportunistic infections emerge.
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Is progression to AIDS a sudden event.
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It is not, but occurrs as a continuum of clinical states. Coinfection with herpes type 6 can transactivate transcription from the silent HIV provirus, increasing HIV replication. T cell precursors are killed, and the capacity to generate CD4+ cells is gradually lost. HIV mutants with altered antigencity appear which are not recognized by the existing humoral A/B or cytotoxic T cell lymphocytes.
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What additional body sites may the HIV virus spread?
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Macrophages are the HIV infected cells present in the brains of patients with AIDS encephalopathy, resulting in dementia.macrophages produce cytokines esp. tumor necrosis factor. Virus is also found in Langerhans cells in skin, dendritic cells in lymphnodes and monocytes in bone marrow. Retinal ischemia is another finding.
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What is the latent period?
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The acute phase viremia is reduced eventually with the appearance of a HIV specific cytotoxic T-lymphocyte response. A latent period lasting from months to many years follows the acute infection.
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List some opportunistic infections seen in AIDS.
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As CD4+ counts decline fungi, viral and bacterial infections abound.
Toxoplasma, cryptococcus, JC virus and mycobacterium. P. jirovecci is a common lung opportunist. |
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What is happening to the provirus during the latent period.
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App 90% of HIV proviruses are transcriptionally silent, so only 10% of the cells containing HIV DNA also contain viral mRNA of viral proteins. The CD4+ count is declining slowly.
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What malignancies are associated with AIDS?
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Kaposi sarcoma, involves skin mucus membranes and viscera. It is associated with Human Herpes virus-8. many other lymphimas are associated with EBV.
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How many virions and CD4 T cells are produced each day?
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It is estimated that app 10(11) virions and 10(9) CD4 T cells are produced daily.
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When is the patient considered to acually have AIDS?
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When the CD4 count falls below 200/ml with the appearance of concurrent disease patterns and opportunistic infections emerge.
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What are some clinical complications of HIV during the latent phase?
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Lymphadenopathy, diarrhea, chronic fevers, night sweats and weight loss. Opportunistic infections such as candidiasis and herpes zoster may periodically occur.
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What additional body sites may the HIV virus spread?
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Macrophages are the HIV infected cells present in the brains of patients with AIDS encephalopathy, resulting in dementia.macrophages produce cytokines esp. tumor necrosis factor. Virus is also found in Langerhans cells in skin, dendritic cells in lymphnodes and monocytes in bone marrow. Retinal ischemia is another finding.
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regarding lab diagnosis which test identies the virus and which the immune response?
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Virus- PCR technique is quite sensitive for early detection of viremia.
Immune response-Elisa is sensitive, but false positives do occur. There is a 25 day window between time virus is in blood and A/B can be detected. All false positives are confirmed with the Western Blot technique. |
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List some opportunistic infections seen in AIDS.
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As CD4+ counts decline fungi, viral and bacterial infections abound.
Toxoplasma, cryptococcus, JC virus and mycobacterium. P. jirovecci is a common lung opportunist. |
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Is progression to AIDS a sudden event.
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It is not, but occurrs as a continuum of clinical states. Coinfection with herpes type 6 can transactivate transcription from the silent HIV provirus, increasing HIV replication. T cell precursors are killed, and the capacity to generate CD4+ cells is gradually lost. HIV mutants with altered antigencity appear which are not recognized by the existing humoral A/B or cytotoxic T cell lymphocytes.
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When is the patient considered to acually have AIDS?
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When the CD4 count falls below 200/ml with the appearance of concurrent disease patterns and opportunistic infections emerge.
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What additional body sites may the HIV virus spread?
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Macrophages are the HIV infected cells present in the brains of patients with AIDS encephalopathy, resulting in dementia.macrophages produce cytokines esp. tumor necrosis factor. Virus is also found in Langerhans cells in skin, dendritic cells in lymphnodes and monocytes in bone marrow. Retinal ischemia is another finding.
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List some opportunistic infections seen in AIDS.
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As CD4+ counts decline fungi, viral and bacterial infections abound.
Toxoplasma, cryptococcus, JC virus and mycobacterium. P. jirovecci is a common lung opportunist. |
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What malignancies are associated with AIDS?
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Kaposi sarcoma, involves skin mucus membranes and viscera. It is associated with Human Herpes virus-8. many other lymphomas are associated with EBV.
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regarding lab diagnosis which test identies the virus and which the immune response?
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Virus- PCR technique is quite sensitive for early detection of viremia.
Immune response-Elisa is sensitive, but false positives do occur. There is a 25 day window between time virus is in blood and A/B can be detected. All false positives are confirmed with the Western Blot technique. |
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What malignancies are associated with AIDS?
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Kaposi sarcoma, involves skin mucus membranes and viscera. It is associated with Human Herpes virus-8. many other lymphimas are associated with EBV.
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regarding lab diagnosis which test identies the virus and which the immune response?
|
Virus- PCR technique is quite sensitive for early detection of viremia.
Immune response-Elisa is sensitive, but false positives do occur. There is a 25 day window between time virus is in blood and A/B can be detected. All false positives are confirmed with the Western Blot technique. |
