Characterization ofPlasmodium falciparum sporozoite surface protein 2 (nalaria/vacdine/thrombospondin related anonymous protein/T-cell Western blot/circumsporozoite protein)

ABSTRACT Immunizationofmice withPasnodiumyoeli sporozoite surface protein 2 (PySSP2) and cfrcumorozoiteprotein protects completely against P. yoelii. The aminoacid sequence of PySSP2 suggested that the thrombospondin-related anonymous protein (TRAP) [Robson, K. J. H., Hall,J. R. S.,Jennings, M. W.,Harris, T. J. R.,Marsh,K., New- bold, C. I., Tate, V. E. &Weatherall, D. J. (1988) Nature (London)335,79-82]isthePlasmodiumfalcqiarumhomologofPySSP2.Wereportdataconfirming thatTRAP isP.falcqiarumSSP2 (PfSSP2). Murine antibodies against recombinant PfSSP2identify a 90-kDaprotein in extracts of P. faiciparum sporozoites, recognizesporozoltes andinfected hepatocytesby Immunofluorescence, localize PfSSP2 tothe sporozoite micro-nemes by immunoelectron microscopy and to the surface membranebyliveimmunofluorescence, andinhibit sporozoiteinvasion and development in hepatocytes in vitro. Human volunteers immunized with irradiated sporozoites and pro-tectedagainstmalariadevelopantibody and proliferativeT-cellresponsestoPfSSP2,