1. If a germs gets through the
physical barriers of the defense
system, it still has to do the battle
with the internal workings of the
immune system.

2. . The reaction of
the body to a
germ that has
gotten in, is
called an immune
response.

3. Imagine that virus has entered your
body and invaded your body’s cells. This
is the immune response that would
follow :
1.Cells called macrophages engulf cells that have
been infected by viruses.
2,The macrophages signal cells called T cells and
cells called B cells.

4. 3.The B cells produce
antibodies, which are substances
that destroy germs.
4. Antibodies attach to other
viruses outside of cells. This
signals other cells to destroy the
viruses.