FIG. 1.

Fractionation of AB serum on a DEAE-Sephacel anion-exchange column. AB serum (3.5 ml) was applied to a 2.5- by 6.5-cm (20-ml) DEAE-Sephacel column. Proteins were eluted (fractions 1 to 5) with Tris-HCl buffer (0.1 M, pH 8.5) and then with 0.1, 0.2, and 0.3 M NaCl in buffer (fractions 6 to 10, 11 to 15, and 16 to 20, respectively). Protein concentrations in 5-ml fractions were estimated by absorbance at 280 nm as given on the vertical axis.