HUMAN IMMUNODEFICIENCY VIRUS

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HUMAN IMMUNODEFICIENCY VIRUS

• Dr. Sarada Devi K.L
• Associate Professor
• Microbiology
• Medical College
• Thiruvananthapuram

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Human Immunodeficiency Virus

• Acquired Immunodeficiency syndrome first
  described in 1981
• Dr Robert Gallo -NIH USA, Dr Luc Montagnier-
• Pasteur Institute-Paris-1983
• HIV-1 isolated in 1983, and HIV-2 in 1985
• Belong to the lentivirus subfamily of the
  retroviridae
• Enveloped RNA virus, 120nm in diameter
• HIV-2 shares 40 nucleotide homology with HIV-1
• Genome consists of 9200 nucleotides (HIV-1)

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Differences between HIV-1HIV-2

• HIV-2 infection- longer latent period
• Lower mother to child transmission rate-HIV-2
• Less efficient rates of sexual transmission
• NNRTI is -not effective for HIV-2

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Family Retroviridae Subfamily Lentivirus

• RNA virus, 120nm in diameter
• Envelope gp160 gp120 gp41
• Icosahedral symmetry
• Nucleocapsid
• Outer matrix protein (p17)
• Major capsid protein (p24)
• Nuclear protein (p7)
• Diploid RNA with several copies of reverse
  transcriptase

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HIV Genome

• 9200 nucleotides (HIV-1)
• env - gp160 (gp120outer membrane part, gp41
  transmembrane part)
• gag core proteins p55, p17 and p24
• pol p66 (protease), p31,p51 (integrase/endonucle
  ase)

EARLY Accessory Genes LATE tat - trans
activator of transcription vif - viral
infectivity factor vpr- viral protein R rev-
regulator of viral protein expression vpu-
viral protein U nef negative regulatory
factor vpx HIV - 2 TAT and REV
are essential for HIV replication
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Genetic variation in HIV

• Mutations occur 65 times more than that observed
  in Influenza virus
• HIV-1 Three groups HIV- 2 eight M (Major)
  subtypes A-H O (Outlier)
• N (New)

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Subtypes of HIV
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Subtypes of HIV-1 M

• 10 Subtypes/Clades/Genotypes Designated A-K
  Differ in Geographical distribution and major
  mode of TransmissionAfrica - A,C , D US and
  Western
• Thailand - E, B Europe - B
• India - C

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Subtyping of isolates

• Done at NARI- Pune CMC Vellore
• Methods 1)Heteroduplex mobility assay (HMA)
• RFLP Analysis
• Nucleotide sequence analysis
• Subtype specific genetic probes

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HIV Replication

• Attachment
• Penetration
• Uncoating
• Reverse Transcription
• Integration
• Replication
• Assembly
• Release

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ENTRY OF HIV INSIDE T CELL
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HIV - Life HistoryCCR5 - the co receptor
HIV
chemokine
Mutant CCR5
CD4
CCR5
CD4
CCR5
CD4
macrophage
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Virion interaction with CD4 receptor and CXCR4
co-receptor
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LIFE CYCLE OF HIV
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Electron micrograph of HIV budding
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HIV and AIDSThe cellular and immunological
picture - The course of the disease
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