Copyright C 1992, American Society for Microbiology Serological Relationship of Tumor Necrosis Factor-Inducing Exoantigens of Plasmodium falciparum and Plasmodium vivax

Exoantigens ofPlasmodium vivax-parasitized erythrocytes stimulated macrophages to secrete tumor necrosis factor, and antisera raised against the exoantigens inhibited this secretion. The antisera also inhibited the activity of Plasmodium falciparum and Plasmodium yoelii exoantigens, and conversely, antisera against the latter cross-reacted with the exoantigens of P. vivax. Tumor necrosis factor (TNF) is thought to be an important factor in the pathogenesis of malaria (4, 5), and there is a good correlation between disease severity and serum con-centrations of TNF in Plasmodium falciparum patients (6, 11, 13). P. falciparum parasitized erythrocytes liberate exo-antigens, probably during schizont rupture (12), which stim-ulate both mouse macrophages (20) and human monocytes (17, 20) to secrete TNF. Plasmodium vivax patients experi-ence paroxysms of high fever, chills, and rigors that coincide with schizont rupture, and their serum contains TNF (3, 9, 15). Further, human mononuclear cells stimulated by P