Vital Checklist Blog
HIV virion contains:
- Enveloped truncated conical capsid (type D)
- 2 copies of single stranded (+) RNA
- RNA dependent DNA Polymerase (Reverse Transcriptase)
- Integrase
- Protease
Gp 120 interacts with CD4+ co-receptors on T-cells
Gp 41 is a fusion protein that fuses with cell membrane to allow entry of the virus.
Gp 24 Capsid- First Antibody detected in HIV infection
| HIV Gene | Products | Function |
| A. Structural Genes- Responsible for the morphology of the virus | ||
| Gag Gene
(Group Antigens) |
Group Specific Antigen
· P 24 · P7P9
· P17 |
Structural proteins
· Capsid Protein · Core Nucleocapsid Protein · Matrix Protein |
| Pol Gene
(Polymerase Gene) |
· Reverse Transcriptase (RNA Dependent DNA Polymerase)
· Integrase
· Protease |
· Produces double-stranded DNA Provirus
· Integrates viral DNA into host cell DNA · Cleaves Viral Poly proteins |
| Env Gene
(Envelope) |
· Gp 120
· Gp41 |
· Surface protein that binds to CD4 receptors and coreceptors: CCR5 (in macrophage)
CXCR4 (in T-Cells) · Helps the virus to fuse with the cell membrane to allow entry into the host cell |
| B. HIV Regulatory Genes | ||
| LTR (U3, U5) | DNA Long Terminal Repeats | Integration and viral gene expression |
| Tat Gene | Transactivator | Up-regulates transcription |
| Rev | Regulatory Protein | Up-regulates transportation of unspliced and spliced Viral genome into the cell cytoplasm |
| Nef | Regulatory Protein | Decreases CD4 and MHC –I expression on host cell. Interferes with T-cell activation pathway
*Required for progression to AIDS |
Laboratory Analysis of HIV
- Initial Screening test: ELISA or Latex Particle Agglutination Test
- Confirmatory Test: Western Blot or Immunofluorescence Test
- Detection of HIV
infection in Neonates
of HIV infected mothers: Polymerase Chain Reaction (Provirus)
- Early Markers of infections: P24 Antigen (Antibodies to P24 antigen develop
quickly)
- Detection of virus in the blood: RT-PCR (Reverse Transcriptase PCR)
- Evaluate Progression of the disease: CD4:CD8 T cell ratio
| Fun Fact:
In an AIDS Patient: 1. Bacillary Angiomatosis : a. Superficial Vascular Proliferation b. Neutrophilic infiltration c. Caused by Bartonella henselae
2. Kaposi Sarcoma: a. Superficial Vascular Proliferation b. Lymphocytic infiltration c. Caused by Human Herpes Virus-8
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