FIG. 1.
Purity of IgG and Fab preparations. (A) Two micrograms of protein was heated in SDS sample buffer and electrophoresed under nonreducing conditions through a 10% Bis-Tris gel with MOPS running buffer. The gels were stained with colloidal Coomassie blue. Molecular mass markers (WM) are indicated in kilodaltons. (B) IgG and (C) Fab were titrated in ELISA against a solid-phase immunoadsorbent of PR8. In each titration, bound Ab was measured with either biotinylated anti-CK (triangles) or anti-CHγ2a, and the assay was developed with streptavidin-AP and pNPP. One of three assays is shown.