Figure 2. Affinity maturation in GCs responding to complex antigens.

Clonal IgGs were generated from antigen-binding pre-immune mature B cells (gray) or day 8 (green) or day 16 (blue) GC B cells from rPA-immunized mice. The distributions of binned avidity indices from clonal IgGs binding to rPA are shown. Clonal IgGs that did not bind antigen were excluded from analysis. The cutoff for antigen binding was set six standard deviations above the mean value for culture supernatants from B-cell-negative samples. Reprinted from (38) with permission.