In areas where malaria is endemic, helminthic infections, caused
by
intestinal or filarial parasites, commonly coexist with
malaria in the same individual. This study investigates the course of
Plasmodium berghei malaria infection in CBA/J mice
inoculated with irradiated attenuated 3rd-stage larvae (L3) of Brugia
pahangi. Peripheral eosinophil counts, serum IgE
levels and cytokine production revealed that the filarial antigen induced
T-helper type 2 (Th2) cell predominance in these
mice, which protected them against the development of cerebral malaria.
These
mice significantly prolonged their survival,
compared with the control mice after P. berghei infection. All
of the
mice not inoculated with irradiated L3 died within
12 days with acute neurological manifestations unrelated to the level of
parasitaemia after infection of P. berghei.
Conversely, most of the inoculated mice lived more than 3 weeks following
infection with P. berghei, dying in the fourth
week of severe anaemia and overwhelming parasitaemia. This suggests that
Th2-dominant responses lead to the downregulation of susceptibility to
murine
cerebral malaria.