How is HIV able to attach to its target T cell?

Answer 1

Im sorry to inform you that the other two answers are only partially correct.It is correct that CD4+ cells get infected, but the viral coat has two proteins gp 120 and gp 40 which are actually resposible for the entry of virus into the T-cell.These after binding to CD4 , undergo conformational changes and the bind to any of the two important chemokine receptors namely CCR5 or CXCR4 receptors on the surface of the T-cell.This is the most important step.Only after this they gain entry.It is purely by lock and key mechanism.The viral protein finds its the best fit on these receptors.
Im a BioTechnologist!!

Answer 2

Viral Attachment:

Once in the body, HIV needs a host to help it reproduce. The host in the case of HIV is the T-cell or CD4 cell. HIV seeks out CD4 cells and must attach to them by way of a "lock and key" type system. Proteins on the surface of HIV attach to complimentary proteins on the CD4 cell much like the way a key fits into a lock. The class of drugs called entry inhibitors (Fuzeon, T-20) block this attachment, preventing HIV from using the T-cell. Once allowed to attach, HIV uses the cell for the next steps in reproduction.



I hope that answered your question...

Answer 3

HIV, as you may have heard, binds to and infects a subset of T cells called "helper T cells".

The molecular "marker" for the Helper T cell is a cell surface receptor, called CD4.

HIV binds to the CD4 receptor, which then causes the Helper T cell to "absorb" the HIV virus RNA code. This RNA code then "hijacks the cells "machinery" by causing it to express it's own HIV genetic code, and to produce an enzyme called Reverse Transcriptase. This enzyme then copies the HIV RNA into a DNA copy, which then inserts itself into the cells DNA. Now, when the synthesizes new DNA and divides, it will also synthesize new HIV DNA as well. When the time, and immune conditions are appropriate for viral infection to ensue, the cells normal gene expression machinery... an enzyme called RNA Polymerase, will generate a new HIV RNA complete genetic code which will again hijack the cells "machinery" (ribosomes, endoplasmic reticulum, etc...) , forcing it to make a new viral coat... thus reconstituting newly multiplied viral progeny, which will kill the CD4 cells in the process and continue the process of increased infection, resulting in increased "viral load" and decreased Helper T cells.

Viruses which infect and replicate in this manner are called "Retroviruses", because they insert their own DNA into the host and are replicated in this manner.