Hypersensitivity
Hypersensitivity is multistep phenomenon that generally requires
(i)
exposure
to
an
antigen,
(ii)
a
dormant
stage
during
which
an
individual
becomes
sensitized,and
(iii)
a
reaction
to
a
subsequent
exposure
to
the
antigen.
The
process
may
involve
humoral
antibodies,
sensitized
T.-Iymphocytes,
or
sometimes
both.
A
response
by
antibodies
to
the
subsequent
dose
of
antigens
often
occurs
early,
say
within
minutes.
This
type
is
known
as
immediate
hypersersitivity.
However,
a
response
by
T-Iymphocytes
usuallly
develops
over
two
or
three
days
and
thus
called
delayed
hypersensitivity.
