Electron microscopy of radiating clubs in tonsillar crypts of swine

Tonsils of 25 adult swine with inflamed crypts were screened for the presence of radiating clubs, and five were selected for electron microscopic study of pathogenesis of clubs. Radiating clubs in crypts were surrounded by an exudate which principally contained neutrophils. Clubs were present on the outer surface of bacterial microcolonies; they also were present on the outer surface of plant particles wedged in crypts or on the cell walls of these particles near bacterial microcolonies. The study demonstrated development of clubs from an amorphous material derived from bacterial and leukocytic cells and also from precipitated proteins. The amorphous material was shaped into clubs by a protracted phagocytic activity of numerous neutrophilic leukocytes. The lesions with radiating clubs within crypts were not surrounded by granulomatous inflammation due to the intact epithelial lining of crypts, and therefore they differ from the granulomas having clubs around microbial colonies. They could, however, serve as models of pathogenesis of radiating clubs in the purulent core of specific granulomas with radiating clubs.