Front Matter

Why are Fetal Neuroantigens Immunogenic to the Maternal Immune System? 239

to sperm antigen may result in low sperm count and infertility [7]. Unfortunately,
the mump vaccine has been reported to induce autoimmune orchitis or infer­
tility. We will return to this topic later in the chapter [8].
Similarly, multiple sclerosis (MS) is considered to be due to leakage of certain
specific types of neuroantigens (myelin) into the patient’s blood circulation. MS
is a disease of the central nervous system (CNS). The CNS consists of the brain,
optic nerves, and spinal cord. In MS patients, the immune system responds by
causing inflammation of the CNS and damaging the myelin sheath (insulated
covering) that protects and covers the axons of the neurons. The damage to the
myelin disrupts the smooth flow of nerve impulses. As a result, the speed of
information from the central location in the brain and spinal cord to other parts
of the body is delayed causing the symptoms observed in MS [9,10]. Figure 8.2
illustrates the autoimmune response to myelin antigen and development of MS.
The good thing about the “immunological privileged” sites is that a “foreign
graft” can be accepeted from other humans without matching the human leuko­
cyte antigens or carrying out “tissue typing”. The antigens inside the privileged

Normal myelin in MS

Cell body

Damaged myelin in MS

Myelin Damaged myelin (demyelination)

Distorted messages

Normal

Nerve fibre (axon)

Figure 8.2 The immunological mechanism that leads to MS. (See insert for color
representation of this figure.)