Page 88 - The Miracle in the Immune System

What Is The MHC (Major Histocompatibility Complex) Molecule?

MHC is a molecule specially created to help the T cells in recognizing the
enemy. They subject the antigen to a series of chemical processes and present it to
the T cells. With the aid of MHC molecules, virus particles, cancer cell molecules,
and even particles belonging to the inner part of a bacterium can be detected.
There is a very important reason for the T cells to use MHC molecules. This
helps them to penetrate host cells and locate camouflaged viruses. However, even
the help of the MHC molecule is not sufficient for T cells to fulfill their function. T
cells also need a helper cell. Called the APC (antigen-presenting cells) for the sake
of brevity, these cells break antigens apart and grab a very important part from the
antigen. This part contains the amino acid sequence that determines the antigen's
identity. The T cell is activated when it receives this identity information from the
APCs.
As we can see, there is a need for a superb sub-system for the defence system
even to start a war. The absence of even a single component of this intelligence
network, made up of many interconnected subunits, would render the system use-
less. Under these circumstances, it would be beyond reason to talk about coinci-
dence in the formation of such an intelligence system. Entertaining such views
would be verging on superstition.
There is wisdom at all levels of this system which Allah has flawlessly created.
An example of this would be the performance of APC cells that bring the enemy to
T cells. These cells are aware that T cells can recognise the enemy from its amino
acid sequence. This is one of the thousands of pieces of evidence that both cells
are created by the same power, that is, Allah.

Either a macrophage or a B cell presents an antigen to a helper T
cell. To accomplish this, the antigen has to be digested to peptides
that are combined with an MHC protein. The complex is presented to
the T cell. In return, the helper T cell produces and secretes lym-
phokines that stimulate T cells and other immune cells.