Identification and partial characterization of exoantigens derived from medium used to culture Plasmodium falciparum.
Rabbits were immunized with exoantigens from the spent medium of Plasmodium falciparum cultures, and the resultant immunologic responses were studied by indirect fluorescent antibody (IFA), hemagglutination (HA), and two-dimensional crossed immunoelectrophoretic (IEP) techniques. By crossed IEP, three parasite antigens, identified and characterized as proteins lacking lipid and carbohydrate moieties, reacted with rabbit antiserum and human immune serum. Pre-immunization sera of the rabbits used in these experiments had 1:80 IFA titers against P. falciparum schizonts which were then boosted eightfold by immunization with parasite exoantigens, in contrast to IFA titers of less than 1:2 for coccidia- and Pasteurella-free rabbits. Experimental infections of coccidia- and Pasteurella-free rabbits with rabbit Eimeria spp. resulted in 1:80 anti-P. falciparum IFA titers, suggesting cross-reactivity of coccidial and plasmodial antigens. Post-immunization sera demonstrated extremely high HA titers against human erythrocytes, underscoring the potency of human blood components containing parasite antigens prepared from cultures. These results suggest that coccidia- and Pasteurella-free rabbits may be useful in the analysis of antigen of cultured P. falciparum.
D000818:Animals; D000954:Antigens, Surface / Q000032:analysis*; D003470:Culture Media; D010963:Plasmodium falciparum / Q000276:immunology*; D011817:Rabbits
D000954:Antigens, Surface; D003470:Culture Media