The predominant theory to explain this phenomenon
is
that
P.
f
al c i par um parasites accumulate
selectively in the placenta, and particular antigenic
variants
interact
with
syncytiotrophoblastic
chondroitin
sulfate
A.
22
Women have a malaria
episode caused by chondroitin sulfate A–binding
parasites during their first pregnancy because they
lack immunity to antigenic variants presented by
these strains (even though they may be immune to
other antigenic variants of parasites that bind endothelial
receptors
from
previous
infections)
and
are
thus
highly
susceptible
to
the
new
infection.