Purified human ApoE binding to mid-exponential S. aureus wild-type (ClfA+) and the isogenic ClfA-deficient mutant (ClfA−) after incubation for 2 h at 37 °C. Cell-wall proteins were solubilized from the washed bacteria and analysed via Western blotting and probing of ApoE. Sequence of lanes on Western blot: A, MagicMark XP Western protein standard; B, ApoE in the wild-type ClfA+ strain cell-wall preparation; C, purified human ApoE (EMD Millipore Chemicals) used as an internal control; D, absence of ApoE binding to cell wall of the ClfA-deficient mutant; E, MagicMark XP Western protein standard.