Understanding HIV and AIDS

• How does the reverse transcriptase enzyme in retroviruses like HIV work?

  • Reverse transcriptase converts the viral RNA into DNA
  • This allows the viral DNA to be integrated into the host cell's genome
  • This is a key step in the retroviral replication cycle
• What is the main component of the viral envelope?

  Glycoprotein
• What unique ability do retroviruses have?

  To cause lymphadenopathy and opportunistic infections
• Which organism causes infections associated with retroviruses?

  Pneumocystis carinii
• What is Toxoplasma gondii associated with?

  Infections in retrovirus patients
• How does HHV-8 infection lead to the development of KS lesions?

  • HHV-8 triggers inflammatory and growth factors
  • These factors promote the proliferation and survival of endothelial cells
  • This leads to the formation of KS lesions
• What are common flu-like symptoms of acute HIV infection?

  Fever, sore throat, and swollen glands
• What is the first opportunistic infection listed for HIV?

  Pneumocystis carinii pneumonia
• How do the effector cytokines produced by the activated CD4+ T cells differ in their functions?

  IFNγ, TNF, IL-17A, IL-17F, IL-2, IL-13 have different effector functions
• What is the fever symptom of acute HIV infection?

  Fever
• How does the role of HHV-8 in KS lesion development differ from the role of HIV-1?

  HHV-8 directly causes the growth and development of KS lesions, while HIV-1 indirectly contributes by weakening the immune system
• What are the 3 main ways children can get HIV from their mothers in the United States?

  in the womb, during birth, from breastfeeding or breast milk
• How does Kaposi's sarcoma develop?

  It develops from HVV-8 infection
• What pathways does HHV-8 activate during its viral cycle?

  Growth and angiogenic pathways
• How do naive CD4+ T cells respond after being activated by the MHC class II-virus-derived peptide complex?

  CD4+ T cell activation, polarization and population expansion
• Why do some patients experience no symptoms during acute HIV infection?

  Many patients experience no symptoms during acute HIV infection.
• What is the significance of the purple virus in the image?

  It represents HHV-8 infecting cells
• What is the role of HHV-8 in relation to Kaposi's sarcoma?

  • HHV-8 infects cells
  • Activates growth and angiogenic pathways
  • Leads to the development of Kaposi's sarcoma
• What is the typical time frame for the first symptoms of acute HIV infection to appear?

  Within 2-4 weeks
• When would you use a scanning electron microscope (SEM) versus a transmission electron microscope (TEM)?

  • SEMs produce 3D images of surface features
  • TEMs produce 2D images by transmitting electrons through thin samples
  • SEMs are used to study surface topography, while TEMs are used to study internal cell structures
• How does virus budding affect CD4+ T cells?

  It lyses and breaks down infected cells
• What was the chance of a pregnant woman with HIV transmitting the virus to her child before 1991?

  25%
• What cancer is commonly associated with HIV?

  Kaposi's sarcoma
• What type of virus is HIV classified as?

  Enveloped retrovirus
• What is the purpose of the fusion step in the HIV life cycle?

  The HIV envelope and the CD4 cell membrane fuse (join together), which allows HIV to enter the CD4 cell
• What are the key steps in the assembly and budding stages of the HIV life cycle?

  • Assembly: New HIV proteins and HIV RNA move to the surface of the cell and assemble into immature (noninfectious) HIV
  • Budding: The immature HIV pushes itself out of the host CD4 cell. Protease breaks up the long protein chains in the immature virus, creating the mature (infectious) virus.
• What are the key steps in the HIV-1 replication cycle?

  1. Binding and fusion of virus to host cell
  2. Reverse transcription of viral RNA to DNA
  3. Integration of viral DNA into host cell genome
  4. Transcription and translation of viral genes
  5. Assembly of new viral particles
  6. Release of new virions from host cell
• What are the two main viral isolates produced in early HIV research?

  LAV and ARV
• What does the image illustrate regarding HHV-8 and Kaposi's sarcoma?

  It shows HHV-8 infecting cells through a viral cycle
• What is the name of the cell shown in the image?

  Naive CD4+ T cell
• What is the name of the transcription factor shown in the image?

  Transcription factor
• What does AIDS stand for?

  Acquired Immunodeficiency Syndrome
• What are the three main mechanisms by which HIV attacks CD4+ T cells?

  1. Virus budding: Lysis of infected cells
  2. Fusion: Merging of infected cells into syncytia
  3. Apoptosis: Induction of programmed cell death
• What is the purpose of the capsid (protein shell) in a non-enveloped virus like Adenovirus?

  The capsid protects the viral genome
• Who discovered LAV?

  French research team
• How has improving treatment helped reduce mother-to-child HIV transmission?

  • Research from the NICHD and others showed that a 3-drug regimen called HAART was better than AZT at preventing mother-to-child transmission.
  • A 2002 study showed that HAART reduced the risk of transmission to 1.2%.
  • HAART became the standard treatment for HIV-positive pregnant women in the United States.
  • Ongoing research, co-funded by NICHD, is looking at the long-term safety of fetal exposure to HAART during pregnancy.
• What is the name of the process shown in the image?

  Gene expression
• Who discovered ARV?

  American research team
• What is the main structural difference between a non-enveloped virus (Adenovirus) and an enveloped virus (Lentivirus)?

  Non-enveloped viruses lack an envelope, while enveloped viruses have an envelope
• What are the key differences between the structures of non-enveloped and enveloped viruses?

  • Non-enveloped viruses lack an outer lipid envelope, while enveloped viruses have an envelope
  • Non-enveloped viruses have a capsid (protein shell) to protect the genome, enveloped viruses have a capsid inside the envelope
  • The envelope of enveloped viruses is derived from the host cell membrane and contains viral proteins