Binding of 4H8, 1A11, and 3H9 to chromatin is unaffected by PNGase F. Relative affinities for chromatin in solid phase ELISA were measured as described in Materials and Methods, and absorbance readings at 405 nm were plotted. Binding of 3H9 (A), 4H8 (B), and 1A11 (C) is shown in red, along with the binding of PNGase F- treated IgG (green), and with IgG incubated in buffer alone (blue). Triplicate values from two separate experiments were averaged, standard errors were computed, and displayed as vertical bars.