Page 42 - The Miracle in the Immune System

40 THE MIRACLE OF THE IMMUNE SYSTEM

sents a wisdom and planning that are too great for the
human mind to comprehend, let alone design.
An unlimited number of combinations can be made
with the use of one hundred thousand genes. The cell,
however, uses, with great intelligence, only 5,200 basic
combinations and produces 1,920,000 specific antibod-
ies. How has the cell learned to make the right combi-
nations out of these unlimited possibilities to form the
required antibodies?
Making the correct combinations out of an infinite
number of possibilities aside, how has the cell got this
idea of making combinations?
Moreover, the produced combinations serve a cer-
tain purpose, and aim to produce an antibody that

An individual B cell makes copies of its own specific anti-
body and attaches them to the outer surface of its cell mem-
brane. The antibodies extend outward like minute, highly
tuned aerials waiting for contact with the specific bit of pro-
tein that they can recognise. An antibody is made of two
light and two heavy chains of amino acids held togeth-
er in a Y shape. The constant regions of chains are
the same in many different types of antibodies.
But the variable regions - the tips of the
Variable region
arms - each have a uniquely shaped
of light chain
cavity that fits exactly onto the
Variable
shape of the antibody's "cho-
Constant region region
sen" protein fragment.
of light chain of heavy
chain
Antibodies
Constant region
of heavy chain

Carbohydrate group

Antigen-
B cell
binding site