Plasmodium berghei: reaction of sporozoites with chemically and enzymatically modified hepatoma cells

Plasmodium berghei sporozoites were observed to react with human hepatoma (HepG2) target cells which had been fixed with methanol, formaldehyde, or glutaraldehyde. The reaction consisted of attachment of sporozoites to the fixed target cells and the release of circumsporozoite protein which bound to target cell areas adjacent to the attachment sites. Treatment of fixed target cells with 0.1 N H2SO4 at 80 C, neuraminidases, neuraminidase plus galactose oxidase or inclusion of transferrin, orosomucoid, their asialo forms, or various monosaccharides in the incubation medium had no significant effect on target cell reactivity with sporozoites. Fixed cells oxidized with periodate or cells extracted with methanol or chloroform-methanol were reactive but lost activity if allowed to air dry after treatment. Treatment with papain or chymotrypsin at levels producing heavy cell structure damage caused a major loss of activity.