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how hiv infection occurs

this is what i understood,
the virus has glycoprotein on the surface which binds to the CD4 receptors in the t helper cells. next the rna enters the thelper cell and does reverse transcriptase. the viral dna is made. now viral proteins and viral replication takes place inside the t helper cell. eventually the t helper cell bursts and dies.
but my question here is, why didnt the phagocyte just engulf the hiv virus before it could attack t helper cell.
and another question is what does t killer cell have to do with this
Original post by Ailurophile03
this is what i understood,
the virus has glycoprotein on the surface which binds to the CD4 receptors in the t helper cells. next the rna enters the thelper cell and does reverse transcriptase. the viral dna is made. now viral proteins and viral replication takes place inside the t helper cell. eventually the t helper cell bursts and dies.
but my question here is, why didnt the phagocyte just engulf the hiv virus before it could attack t helper cell.
and another question is what does t killer cell have to do with this



Normally phagocytes enter the play when the pathogen is outside the host cell.
For phagocyte to work out in cell mediated response we need t-helper cells to be activated but by the time this happens, huge no. of t-helper cells die out viral lysis.
T- killer cells and antibodies are the ones tackling the pathogen in cell mediated response. T- killer cells in our case cant be formed since t-helper cells arent activated yet.
(edited 4 years ago)
Reply 4
Phagocytes mostly engulf bacteria,while virus are 100 times smaller than bacteria
Also phagocytes need opsonin to guide them to microorganisms and opsonin is released by antibody after t-helper has been infected (humoral response) so phagocytes can't engulf them beforehand.

T-killer cells bind to heavily infected T-helper cells and release lysosome enzyme to do lysis(destroy t-helper cell)so that t-helper cell burst open,
Most of the time virus assembly to destroy t-helper but sometimes t-killer cells destroy them if virus detected
(edited 4 years ago)
Original post by Roha125
Phagocytes mostly engulf bacteria,while virus are 100 times smaller than bacteria
Also phagocytes need opsonin to guide them to microorganisms and opsonin is released by antibody after t-helper has been infected (humoral response) so phagocytes can't engulf them beforehand.

T-killer cells bind to heavily infected T-helper cells and release lysosome enzyme to do lysis(destroy t-helper cell)so that t-helper cell burst open,
Most of the time virus assembly to destroy t-helper but sometimes t-killer cells destroy them if virus detected

ohh
i thought phagocyte engulfs first, than antigen represent on the phagocyte. then t helper cell binds to it and activates t killer cell and b cell
Original post by lyer_in_hellfyre
Normally phagocytes enter the play when the pathogen is outside the host cell.
For phagocyte to work out in cell mediated response we need t-helper cells to be activated but by the time this happens, huge no. of t-helper cells die out viral lysis.
T- killer cells and antibodies are the ones tackling the pathogen in cell mediated response. T- killer cells in our case cant be formed since t-helper cells arent activated yet.

thank u, so basically the hiv virus just enters the t helper cell and kills it by lytic. t killer cell wont be made and no antibody too cause no b cell activated?
Reply 7
Original post by Ailurophile03
ohh
i thought phagocyte engulfs first, than antigen represent on the phagocyte. then t helper cell binds to it and activates t killer cell and b cell

Yes,even that occurs,you are right but for this case HIV is very small so gets mostly undetected by phagocytes
Some will get detected which will cause the start of response you just said.
All HIV doesn't get engulfed by phagocytes and 1 hiv is needed to start virus multiplication and virus have specfic receptors which helps to directly go for t-helper receptors
Original post by Ailurophile03
thank u, so basically the hiv virus just enters the t helper cell and kills it by lytic. t killer cell wont be made and no antibody too cause no b cell activated?


Np, (thank u 2 lol i got to revise ^^ )yeah hiv stays dormant for a very long time before it kills by lytic
I also would agree w/
Original post by Roha125

Also phagocytes need opsonin to guide them to microorganisms

Usually phagocytes are attracted to
-chemicals released by pathogen (toxin)
-dead, damaging abnormal cells
-opsonin (also known as antibody and immunoglobin)
In hiv's case it doesnt produce any toxin, nor is the host cell t helper cell abnormal or dead which leaves us the last factor opsonin. But for opsonin to be produced, b effector cells need to be activated which isnt in our scenario cuz t helper cell isnt activated
(edited 4 years ago)
Original post by Roha125
Phagocytes mostly engulf bacteria,while virus are 100 times smaller than bacteria
Also phagocytes need opsonin to guide them to microorganisms and opsonin is released by antibody after t-helper has been infected (humoral response) so phagocytes can't engulf them beforehand.

T-killer cells bind to heavily infected T-helper cells and release lysosome enzyme to do lysis(destroy t-helper cell)so that t-helper cell burst open,
Most of the time virus assembly to destroy t-helper but sometimes t-killer cells destroy them if virus detected


Antibody is the opsonin tho
References pages @Ailurophile03

Spoiler

(edited 4 years ago)
Original post by Roha125
Yes,even that occurs,you are right but for this case HIV is very small so gets mostly undetected by phagocytes
Some will get detected which will cause the start of response you just said.
All HIV doesn't get engulfed by phagocytes and 1 hiv is needed to start virus multiplication and virus have specfic receptors which helps to directly go for t-helper receptors

thank u i understand
Original post by lyer_in_hellfyre
References pages @Ailurophile03

Spoiler



thank u soo much
Original post by Ailurophile03
thank u soo much


:ta: u 2
Well it seems everything was sorted before I came here :redface:.
GL with your revision ppl :h:.
Original post by Ailurophile03
this is what i understood,
the virus has glycoprotein on the surface which binds to the CD4 receptors in the t helper cells. next the rna enters the thelper cell and does reverse transcriptase. the viral dna is made. now viral proteins and viral replication takes place inside the t helper cell. eventually the t helper cell bursts and dies.
but my question here is, why didnt the phagocyte just engulf the hiv virus before it could attack t helper cell.
and another question is what does t killer cell have to do with this

Pretty much everything has been answered already but one thing I may add is that HIV also infects macrophages as well ,since they express the same receptors they use to gain entry into CD4 T cells.

Macrophages also secrete cytokines which bring more T cells into an infected area which means more Helper T cells for the HIV to infect when it comes out of the macrophage.

Since macrophages are antigen presenting cells ,when the infected macrophage presents to the CD4 helper T cell, the helper T cell gets infected by HIV.
It seems from your comments you were thinking among those lines.
(edited 4 years ago)

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