CD4(+) T cells are necessary for a protective immune response against
the erythrocytic stages of the malaria parasite Plasmodium chabaudi ch
abaudi AS. B cells are not required for control of early acute parasit
aemias, but appear to be important for final clearance of the infectio
n, most probably by producing specific antibodies against the parasite
. However, immune sera and immune IgG are unable to replace the protec
tive capacity of B cells in adoptive transfer of immunity to P. chabau
di AS. It is therefore conceivable that B cells are required to achiev
e protective immunity, not only as effector plasma cells, but because
they may also play a second important role. We have recently suggested
that B cells may regulate the Th response to P. chabaudi AS during a
primary infection. We discuss here the possibility of a dual requireme
nt of B cells in achieving protective immunity to P. chabaudi AS.