PfEMP1 expression in trophozoite-stage cultures of unselected 3D7 (3D7UM), 3D7 selected for expression of VSASM-type IE surface antigens (3D7SM) and of NF54 established from six volunteers on different days after infection. A: Western blot using antibodies (αATS) targeting the acidic terminal segment (ATS), which is conserved between most PfEMP1 types. Black arrows indicate changes in protein expression between isolates of the same volunteer. B: Western blot identifying the αATS-detected 400 kDa band in the day 10 culture of volunteer 1 as PFD1235w/VAR4 using an αDBL5δ antibody. VAR4 is expressed on the surface of the 3D7SM line selected for high immune serum recognition .