ACTIVITY OF HUMAN VOLUNTEER SERA TO CANDIDATE PLASMODIUM-FALCIPARUM CIRCUMSPOROZOITE PROTEIN VACCINES IN THE INHIBITION OF SPOROZOITE INVASION ASSAY OF HUMAN HEPATOMA-CELLS AND HEPATOCYTES

Sera from human volunteers immunized with either synthetic peptide (NANP)3-TT or recombinant protein R32tet32Plasmodium falciparum CS vaccines were tested in the inhibition of sporozoite invasion (ISI) assays using human hepatoma (HepG2-A16) cells or primary human hepatocytes. Sera or purified immunoglobulin (Ig) from volunteers who were completely protected against P. falciparum sporozoite challenge had higher ISI activity than sera from non-protected volunteers, or the highest titre endemic serum. However, Ig from protected and non-protected volunteers did not block sporozoite invasion of human hepatocytes, suggesting that P. falciparum sporozoites invade hepatocytes by mechanisms which differ from those concerned with invasion of HepG2-A16 cells. © 1990, Royal Society of Tropical Medicine and Hygiene. All rights reserved.