Figure 1.

Soluble Aβ is recovered after immunoprecipitation with antibodies to apoE or Aβ in AD brains. Both polyclonal antibodies R3660 (specific for the amino-terminal portion of Aβ) and AB947 (to human apoE) immunoprecipitate (IP) Aβ peptides detected as two bands of 4.5 and 4.2 kDa after immunostaining with the Aβ monoclonal antibody 6E10 in AD brains only. Control (CO) brains are not immunoreactive irrespective of their apoE genotype (3/3, etc.). The presence of Aβ peptides immunoprecipitated with the antibody AB947, specific to apoE, indicates that a portion of the soluble Aβ is bound to apoE and separates in SDS/PAGE. The synthetic peptide Aβ-(1–42) comigrates with the upper band in AD samples.