In high-CLIP-affinity Ii transfectants, total cellular abundance of I-Ag7 is increased and abundance of high-CLIP-affinity Ii is decreased. (A) Steady-state levels of I-Ag7β, β-actin, total Ii and transfected 6×His-Ii in stable 3A5.g7 Ii transfectants were assessed by western blotting (antibodies: 10-2.16, anti-actin, In-1 and anti-Tetra-His, respectively). Lysates were normalized for protein amount (shown: 25 μg per lane). One representative experiment of several is shown. (B) Densitometry from several experiments (normalized to the appropriate untagged or 6×His-tagged wt Ii sample within each experiment). Statistical significance was determined by Wilcoxon signed ranks test: *P = 0.0156; **P = 0.0078; ***P < 0.005. All indicated comparisons remain statistically significant after sequential Bonferroni correction for multiple comparisons.