Figure 5.

Histones are abundant in the plastic bronchitis airway cast proteome, and histone H4 is evident by immunofluorescence (IF) staining. (A) Histone H4 is the most abundant of the histones and is the eighth most abundant protein in the airway cast proteome. Another nuclear protein, high mobility group protein B1 (HMGB1), which is indicative of cell necrosis, had a similar abundance to histones in the cast proteome. (B) Representative IF micrograph (original magnification, ×100) of an airway cast section stained for histone H4 (red), DNA (blue), and annexin A5 (green) that illustrates the distribution of intracellular and nuclear material in plastic bronchitis airway casts. Representative IF of control slides that demonstrate antibody specificity and performance can be found in Figure E2. Data represented in (A) are the normalized spectral abundance factors of each respective protein in each of three plastic bronchitis airway casts.