So, let's go back to what we were talking about before in
terms of the immune effector cells-
the cells that actually do the work of the immune system fighting against HIV.
I mentioned that B cells are antibody-producing cells.
CD4 cells are also called T-helper cells.
They're the central orchestrator of immune function and I mentioned that
CD8 T cells are killer T cells that kill virus-infected cells.
Let's go into this now in a little bit more detail to
understand exactly how these processes happen.
So, the question is, how does the immune system fight HIV?
One of the ways is by the development of HIV specific B cells,
which you remember when they encounter virus-infected cells,
there is a small subset of those cells that
recognize through their B cell receptor the HIV envelope protein,
and those then proliferate robustly and begin to
secrete, essentially, copies of
the B cell receptor that are soluble forms that are called antibodies.
Some of these antibodies are neutralizing antibodies, meaning that they can
directly bind to the virus and neutralize its ability to cause an infection.
Ideally, what we would be able to do is have
a vaccine induce antibodies to HIV that would prevent
an infection from ever happening by binding to the virus before
it can even infect a CD4 cell or if a CD4 cell is infected,
to be able to bind to virions that are being produced and
neutralize them so they can't go on to infect other cells.
The reality is when the discovery of HIV was first made,
Margaret Heckler, then the Director of Health and Human Services,
predicted that within a couple of years,
we would have a vaccine to prevent HIV infection,
anticipating that it would be relatively easy to generate antibodies,
now that we knew what the virus was and we had something to work with.