Impaired accessibility of the pRBC surface for anti-PfEMP1 antibodies within a rosette as seen by indirect immunofluorescence: FCR3S1.2 pRBC were labelled with anti-DBL1α antibodies visualized in confocal microscopy using 10 μg/ml anti-DBL1α goat IgG and anti-goat-Alexa488. PfEMP1 expressed on the pRBC surface is labelled, but antibodies are hampered in accessing PfEMP1 by uninfected RBC bound to the pRBC surface. pRBC in smaller rosettes as in blood group O (upper panel) are more accessible as compared to pRBC in larger rosettes with more RBC as in blood group A (middle panel). Staining over the whole pRBC surface is seen for non-rosetting pRBC (lower panel). staining of live pRBC with strain specific pgIgG showed stronger labelling of the pRBC in rosettes of blood group O as compared to blood group A labelling over the whole pRBC-surface was observed with pRBC not incorporated in a rosette.

Moll K, Palmkvist M, Ch'ng J, Kiwuwa MS, Wahlgren M. Evasion of Immunity to Plasmodium falciparum: Rosettes of Blood Group A Impair Recognition of PfEMP1. PLoS One. 2015 Dec 29;10(12):e0145120.