DOWN-REGULATION OF MURINE SUSCEPTIBILITY TO CEREBRAL MALARIA BY INOCULATION WITH 3RD-STAGE LARVAE OF THE FILARIAL NEMATODE BRUGIA-PAHANGI

In areas where malaria is endemic, helminthic infections, caused by in testinal or filarial parasites, commonly coexist with malaria in the s ame individual. This study investigates the course of Plasmodium bergh ei malaria infection in CBA/J mice inoculated with irradiated attenuat ed 3rd-stage larvae (L3) of Brugia pahangi. Peripheral eosinophil coun ts, serum IgE levels and cytokine production revealed that the filaria l antigen induced T-helper type 2 (Th2) cell predominance in these mic e, which protected them against the development of cerebral malaria. T hese mice significantly prolonged their survival, compared with the co ntrol mice after P. berghei infection. All of the mice not inoculated with irradiated L3 died within 12 days with acute neurological manifes tations unrelated to the level of parasitaemia after infection of P. b erghei. Conversely, most of the inoculated mice lived more than 3 week s following infection with P. berghei, dying in the fourth week of sev ere anaemia and overwhelming parasitaemia. This suggests that Th2-domi nant responses lead to the downregulation of susceptibility to murine cerebral malaria.