Page 77 - The Miracle of 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 parti-
cles 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 net-
work, made up of many interconnected subunits, would render the system useless.
Under these circumstances, it would be beyond reason to talk about coincidence in
the formation of such an intelligence system. Entertaining such views would be verg-
ing on superstition.
There is wisdom at all levels of this system which has been flawlessly created by
Allah. 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 recognize 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 ac-
complish 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 lymphokines that stimulate T cells and
other immune cells.