Human Immunodeficiency Virus (HIV)
INTRODUCTION:
- Causative agent of AIDS(Slim disease)
- Discovered by Luc Montagnier of France in 1983
- HIV is found in Blood, Semen, Saliva
- HIV is highly mutable virus
- HIV prevalence can be assessed by Sentinel surveillance
- Oncogenic reterovirus
Taxonomy
| Group: | Group VI (ssRNA-RT) |
| Order: | Unassigned |
| Family: | Retroviridae |
| Subfamily: | Orthoretrovirinae |
| Genus: | Lentivirus |
Types
- Two types are found HIV 1 and HIV 2.
- HIV 1 most common
MORPHOLOGY:
- Spherical enveloped virus
- Nucleocapsid has icosahedral
- Contain RNA genome and RNA-directed DNA polymerase (reverse transcriptase)
- Two viral strands of RNA found in core surrounded by protein outer coat.
- Genome is diploid, composed of two identical single-stranded, positive sense RNA copies.
- Outer envelope contains a lipid matrix within which specific viral glycoproteins are imbedded.
- HIV contains Integrase , RNA directed DNA polymerase ,Ribonuclease
- External spikes responsible for binding to target cell.
- Boiling, Ethanol, Cidex can destroy HIV in vitro
STRUCTURAL GENES:
- Three main structural genes:
- Group Specific Antigen (Gag)
- Envelope (Env)
- Polymerase (Pol)
Group Specific Antigen (Gag)
- Located in nucelocapsid of virus.
- Codes for core and shell of HIV
- Code for precursor protien p55
- p55 cleaved into p24, p18 and p15
Envelope (Env) gene
- Code for the synthesis of envelope glycoprotein gp 160
- gp 160 cleaved by proteases to become HIV envelope glycoproteins gp120 and gp41.
- gp120 and gp41 both involved with fusion and attachment of HIV to CD4 antigen on host cells.
Polymerase (Pol)
- Codes for p66 and p51 subunits of reverse transcriptase and p31 an endonuclease.
- Located in the core, close to nucleic acids.
- Responsible for conversion of viral RNA into DNA
- Integration of DNA into host cell DNA
- Cleavage of protein precursors.
OTHER GENES
- tat, rev , jej, vif, vpu, vpx, vpr, LTR.
- HIV 2 lacks vpu gene
- HIV 2 have vpx gene which is not present in HIV 1.
GROUPS of HIV 1
- Group M (Most of infection)
- Group O
- Group N
- Nine subtypes of M
- Subtype C is most prevelant worldwide
- Europe, Australia and America subtype B is predominant
- ln lndia and China subtype C predominant.
Exam Important
- Family retrovirdae; subfamily lentivirdae
- HIV prevalence can be assessed by Sentinel surveillance
Oncogenic reterovirus
- Contain RNA genome and RNA-directed DNA polymerase (reverse transcriptase)
- Genome is diploid
- HIV contains Integrase , RNA directed DNA polymerase ,Ribonuclease
- Boiling, Ethanol, Cidex can destroy HIV in vitro
Group Specific Antigen (Gag)
- Codes for core and shell of HIV
Envelope (Env) gene
- gp120 and gp41 involved with fusion and attachment of HIV to CD4 antigen on host cells.
Don’t Forget to Solve all the previous Year Question asked on Human Immunodeficiency Virus (HIV)
Click Here to Start Quiz
Click Here to Start Quiz
