Cito di Pense wrote:Detection. How does it work?
I should probably thank you for your little rant, due to what I found out about AIDS
And it is far more interesting than what I had last heard on the subject years ago and my memory of it was obviously wrong also.
But before explaining about AIDS I'll explain the initial question.
How do T cells "see?"
Previously I thought T cells produced antibodies on the surface of their cell (by way of a process I had no idea about) and these antibodies attached themselves to an antigen so the T cell could destroyed that antigen. But it is only the B cell that produces antibodies on its cell surface, which then attach themselves to an antigen, in order to make antibodies for that specific antigen, and then releases those antibodies into the blood stream. B cells do not destroy an antigen though, they just produce antibodies.
The released antibodies then attach themselves to the specific antigen's they were made for and the T killer cell then attaches itself to the antibody and kills the antigen.
The "seeing" is when the protein chain at the tip of an antibody bumps into an antigen and attaches itself to that antigen. This is a random process but works due to the shear numbers of antibodies that have been released into the body which are constantly bumping into everything as they travel around the blood and body. When the tip of the antibody bumps into a certain part of the antigen and if the shape of the tip of the antibody fits nicely and neatly into that part of the antigen, plus as long as forces such as Van der Vaals forces and hydrogen bonding forces allow the antigen and antibody to lock into place, "seeing" has occurred. This same process allows the T killer cell to attach itself to the antibody, so the antigen can be destroyed.
I did read up on the whole process of how antibodies are produced and attach themselves to antigens, but it would take too much time and effort to explain everything involved. But the process of "seeing" isn't too different to what I initially thought, I was 100% incorrect in that I thought antibodies were on the surface of the T killer cell though.
But where I was incredibly wrong is how HIV causes AIDS. I thought the HIV infected and killed all the T helper cells, but this is not the case.
A very brief summary of how the body reacts to HIVThe most interesting part of what I read was that HIV infection only accounts for about 5% of all T helper cell deaths, the remaining 95% of T helper cell deaths occur by way of pyroptosis (cell death by way of inflammation) with these cells not being infected by HIV. Although HIV has not infected these 95% of cells, HIV is indirectly responsibly for the death of these cells.
Before reading up on this, I thought HIV infected a T helper cell and then destroyed the cell, after replicating itself, when the newly produced HIV were released into the body. But this is not the case for RNA viruses. Although HIV infects the T helper cell to reproduce itself, the newly created HIV escape through the membrane of the T helper cell without destroying it. When the T helper cell does get destroyed, due to HIV infection, it is though various forms of apoptosis (self destruction) or a T killer cell will kill the infected T helper cell by detecting antibodies that have placed themselves on the surface of the infected T helper cell. But these forms of destruction account for only 5% of all T helper cells deaths.
95% of T helper cell deaths occur in the lymph glands. Because T cells are constantly entering end exiting the lymph gland, there is a very heavy concentration of T cells in the lymph gland. The process where by the deaths occur is: When an abortive T helper cell (a cell not infected by HIV but has HIV proteins in on on it) enters a lymph gland and self destructs by way of pyroptosis (a form of cellular self destruction induced by inflammation) it releases cytokines (which induce inflation in cells) on mass which intern induce inflation in surrounding T helper cell which also undergo pyroptosis and release even more cytokines and so on. This creates an destructive cycle of T helper cell pyroptosis induced again and again by the constant release of cytokines. And this accounts for 95% of helper T cell destruction in AIDS patients.
So the HIV doesn't actually destroy the T helper cell 95% of the time, HIV is only responsible for T helper cell death 5% of the time, and this 5% is due to cellular self destruction. So theoretically HIV doesn't destroy any cells at all, but HIV is indirectly responsible for 100% of the T helper cell deaths. To say HIV doesn't destroy T helper cells without an explanation would be incredibly misleading.
References:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4047036/https://aidsinfo.nih.gov/understanding- ... life-cyclehttps://www.ncbi.nlm.nih.gov/pmc/articl ... figure/F5/https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4835240/
by 
