ABSENCE OF SPOROZOITE-NEUTRALIZING ACTIVITY OF ANTIBODIES RECOGNIZINGTHE PLASMODIUM-FALCIPARUM SEXUAL STAGE ANTIGEN PFS16

Pfs16 was isolated independently by two groups of researchers either b y screening cDNA and genomic expression libraries with monoclonal anti bodies raised against purified gametocytes of Plasmodium falciparum, o r by a substractive cloning strategy. Expression of this antigen has b een found unambiguously in gametocytes by both teams but in sporozoite s by only one group Moreover, the latter group reported that antibodie s raised against recombinant Pfs16 proteins could prevent sporozoite p enetration into human hepatoma cells and human hepatocytes. In contras t we have found that monoclonal and polyclonal antibodies specifically recognizing Pfs16 in gametocytes do not react with sporozoites. Moreo ver, they were shown io hove no inhibitory activity against P. falcipa rum sporozoite penetration in human hepatocytes.