Disruption of the C-terminal region of EBA-175 in the Dd2/Nm clone of Plasmodium falciparum does not affect erythrocyte invasion

EBA-175 is a Plasmodium falciparum micronemal protein that binds to sialic acid in the context of the peptide backbone of glycophorin A and has been i mplicated in sialic acid-dependent invasion of erythrocytes. The existence of an alternative invasion pathway has been suggested by the finding that t he P. falciparum clone Dd2/Nm can invade sialic acid-depleted erythrocytes. To study the role of EBA-175 in this alternative pathway, we have generate d Dd2/Nm clones expressing a truncated form of EBA-175 that lacks region 6 and the cytoplasmic domain. The protein still appears to be localized to th e apical end in the vicinity of the micronemes, suggesting that region 6 an d the cytoplasmic domain are not involved in EBA-175 trafficking to the mic ronemes. In these genetically modified clones, the level of truncated EBA-1 75 protein expression was greatly reduced. EBA-175-disrupted clones display ed normal rates of invasion of untreated and enzyme-treated human and anima l erythrocytes, suggesting a lack of involvement of EBA-175 in this alterna tive invasion pathway. (C) 2000 Published by Elsevier Science B.V.