Antibodies to the glutamate dehydrogenase of Plasmodium falciparum

Polyclonal antisera raised against Plasmodium knowlesi reacted with NADP-specific glutamate dehydrogenase (GLDH) of P. knowlesi, GLDH of P. falciparum and GLDH of Proteus spp. The antisera did not react with NAD(P) GLDH from bovine liver. Polyclonal antisera raised against the GLDH of Proteus spp. cross-reacted with GLDH from P. falciparum. Monoclonal antibodies (McAbs) obtained from mice immunized with Proteus GLDH were either specific for the bacterial enzyme or cross-reacted with P. falciparum GLDH. The selected McAbs did not react with GLDH from P. knowlesi, P. chabaudi or P. berghei. The GLDH of P. falciparum was shown to be a cytosolic protein (by FAT) with a subunit molecular weight of approximately 49 000 Da (by immunoprecipitation) having a predominantly hexameric form (by sucrose density gradient). Implications of the conserved sequences of GLDHs and other enzymes are discussed.