Page 89 - The Miracle of the Immune System

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Step By Step To All-Out War

sets off a general alarm in the body to increase the body temperature.
Macrophages have yet another important characteristic. When a ma-
crophage cell captures and engulfs a virus, it tears off a special portion of
the virus, which it carries on itself like a flag. This serves as a sign for the
other elements of the defence system as well as an item of information.
Once the gathered intelligence is forwarded to the helper T cells, by
the help of which they identify the enemy, their first task is to immediate-
ly alert the killer T cells, stimulating them to multiply. Within a short pe-
riod, the stimulated killer T cells will become a formidable army. This is
not the only function of the helper T cells. They also ensure that more pha-
gocytes arrive at the battlefront while they transfer the gathered intelli-

gence relating to the enemy to the spleen and lymph nodes.
Once the lymph nodes receive this information, the B cells, which
have been waiting for their turn, are activated. (The B cells are manufac-
tured in the bone marrow and then migrate to the lymph nodes to wait for
their turn to be of service).
The activated B cells go through a number of stages. Every stimulat-
ed B cell begins to multiply. The multiplication process continues until
thousands of identical cells are formed. Then, the B cells, which are ready
for war, start to divide and are transformed into plasma cells. Plasma cells
also secrete antibodies, which will be used as weapons during the fight
with the enemy. As stated in earlier chapters, B cells are capable of pro-
ducing thousands of antibodies in a second. These weapons are very
handy. They are capable enough to bind to the enemy first, and then to de-
stroy the biological structure of the enemy (antigen).
If the virus penetrates the cell, the antibodies cannot capture the virus.
At this point, the killer T cells come into play again and, by identifying the

viruses in the cell with the help of MHC molecules, they kill the cell.
However, if the virus has been successfully camouflaged, escaping
even the notice of killer T cells, then "natural killer cells", briefly called
NKs, swing into action. These cells destroy the cells which host viruses in
them, and which are imperceptible to other cells.