Download - HUMAN IMMUNODEFICENCY VIRUS (HIV)
HUMAN IMMUNODEFICENCY HUMAN IMMUNODEFICENCY VIRUS (HIV)VIRUS (HIV)
INTRODUCTIONINTRODUCTION
HIV VIRUS IS HUMAN HIV VIRUS IS HUMAN
IMMUNODEFICENCY VIRUS IT IMMUNODEFICENCY VIRUS IT
CAUSES (ACQUIRED CAUSES (ACQUIRED
IMMUNODEFICENCY SYNDROME)IMMUNODEFICENCY SYNDROME)
(AIDS)(AIDS)
HIV VIRUS exists as roughly HIV VIRUS exists as roughly
spherical particles surface pf spherical particles surface pf
each particle has studded spikes each particle has studded spikes
outside the human body called outside the human body called
as virions or in infected immune as virions or in infected immune
cellscells
TAXONMICTAXONMIC STATUS: STATUS: GROUPGROUP: : GROUPVI (ss RNA_RT)GROUPVI (ss RNA_RT) FAMILYFAMILY: : RETROVIRIDAERETROVIRIDAE GENUS: GENUS: LENTIVIRUSLENTIVIRUS
The viruses of Lentivirus family cause diseases in The viruses of Lentivirus family cause diseases in
monkeys cattle sheep, cats and goats. HIV is a monkeys cattle sheep, cats and goats. HIV is a
retrovirus .it is host specific virus. It was discovered retrovirus .it is host specific virus. It was discovered
in monkeys for the first time but it does not affect in monkeys for the first time but it does not affect
the monkeys rather causes aids in humansthe monkeys rather causes aids in humans
TYPES OF HIV VIRUS:TYPES OF HIV VIRUS:
It has two types HIV- 1 AND HIV- 2.It has two types HIV- 1 AND HIV- 2. TYPE 1 is highly infectious and causes 90%of TYPE 1 is highly infectious and causes 90%of
the infection globally.the infection globally. HIV-2 is found in west Africa and confined thereHIV-2 is found in west Africa and confined there
SpecieSpecie VirulenceVirulence InfectivityInfectivity PrevalencePrevalence OriginOrigin
HIV-1HIV-1 HighHigh HighHigh GlobalGlobal ChimpanzeChimpanzeee
HIV-2HIV-2 LowLow LowLow West West AfricaAfrica
Sooty Sooty MangabeyMangabey
MORPHOLOGYMORPHOLOGY
SIZE:SIZE:0.1micron0.1micron1/201/20thth of the length of an inch of the length of an inchIt is too small to be seen with It is too small to be seen with
an a compound microscope an a compound microscope and it is visible with the and it is visible with the electron microscope.electron microscope.
Structure:Structure:
HIV is a retrovirusHIV is a retrovirus
It has an enzyme (reverse It has an enzyme (reverse
trancriptase trancriptase which converts which converts
single stranded RNA to single stranded RNA to
double stranded DNA)double stranded DNA)
It has a coat of fatty material It has a coat of fatty material
called as viral envelope or called as viral envelope or
capsidcapsid
It has 72 little spikELTS It has 72 little spikELTS
projecting from the capsid.projecting from the capsid.
ENZYME AND PROTIEN ENZYME AND PROTIEN STRUCTURESTRUCTURE
VIRAL ENVELOPE:VIRAL ENVELOPE: The envelope is made up of gp120 and gp 4 and The envelope is made up of gp120 and gp 4 and
gp4 .just below the viral layer is made from gp4 .just below the viral layer is made from protein p17.protein p17.
Capsid is made up of p24 it is bullet shape.Capsid is made up of p24 it is bullet shape.
EnzymesEnzymes Integrase Integrase ProteaseProtease Reverse transcriptaseReverse transcriptase
Diagram explaining a retrovirusDiagram explaining a retrovirus
GenomeGenome
The HIV virus is a retrovirus it has single The HIV virus is a retrovirus it has single stranded RNA in its genome and it does not stranded RNA in its genome and it does not have a complex genome it ois comprised of 9 have a complex genome it ois comprised of 9 genes onlygenes only
3 are (3 are (gag pol env) these are encoded to gag pol env) these are encoded to make new virus particlesmake new virus particles
The rest 6 (The rest 6 (tat ,rev ,nef, vif, vpr, and vpu) tat ,rev ,nef, vif, vpr, and vpu) are used in the formation of proteins are used in the formation of proteins that control the ability of HIV to infect a that control the ability of HIV to infect a cell and cause diseasecell and cause disease
Lifecycle of HIV virus:Lifecycle of HIV virus:
Entry: Entry: The first step of the lifecycle of HIV The first step of the lifecycle of HIV is its attachment on the CD4 receptor site is its attachment on the CD4 receptor site of the of the helper Thelper T cellcell where it s spikes stick where it s spikes stick to the protein of to the protein of CD4CD4 site site
REVERSETRANSCRIPTION AND REVERSETRANSCRIPTION AND INTEGRATION: INTEGRATION: once inside the cell the HIV once inside the cell the HIV enzyme enzyme REVERSETRANSCRIPTASEREVERSETRANSCRIPTASE converts the single stranded mRNA into converts the single stranded mRNA into double stranded DNA using the host double stranded DNA using the host genome which is compatible to host genome which is compatible to host genome .The enzyme genome .The enzyme INTEGRASE slices INTEGRASE slices the human dna into viral DNA.the human dna into viral DNA.
Transcription and translation: Transcription and translation: HIV is a HIV is a provirus it stays in host genome for a long time .It becomes provirus it stays in host genome for a long time .It becomes activated and expressed in the same way as the human activated and expressed in the same way as the human genes .the mRNA is used as blue print to make new HIV genes .the mRNA is used as blue print to make new HIV virus copies viral proteins and enzymes .virus copies viral proteins and enzymes .
Assembly budding and integration: Assembly budding and integration: when the cell produces and translates mRNA when the cell produces and translates mRNA copies they are the complete copies of HIV copies they are the complete copies of HIV material and they gather together with the newly material and they gather together with the newly made HIV proteins and enzymes to form new viral made HIV proteins and enzymes to form new viral proteins which are released from the cell .Enzyme proteins which are released from the cell .Enzyme Protease Protease plays an important role in chopping up of plays an important role in chopping up of DNA strands to make anew viral core. the new DNA strands to make anew viral core. the new vcirions are ready to infect other cells and they vcirions are ready to infect other cells and they grow and mature by body fluids.grow and mature by body fluids.
Diagram of lifecycle of HIVDiagram of lifecycle of HIV
Electron microscopeElectron microscope
Electron Microscope slide showing virus transmission from cell membrane of T helper cell
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