Migratory Response of Granulomatous Alveolar Cells from BCG-Sensitized Rabbits

Abstract

Rabbits sensitized subcutaneously with bacillus Calmette Guérin (BCG) in oil routinely developed dermal tuberculin sensitivity but failed to develop pulmonary granulomas. Alveolar cells procured from such animals were not always inhibited by purified protein derivative (PPD) in the migration-inhibition test. In contrast, the majority of rabbits sensitized with the same dose of BCG by the intravenous route developed a pulmonary granulomatous response reflected by increased lung weight/body weight ratios and increased numbers of alveolar cells. The majority of such animals did not develop dermal tuberculin sensitivity. However, the granulomatous alveolar cells obtained from rabbits sensitized by the i.v. route were consistently inhibited by PPD in the migration-inhibition test. Alveolar cells procured from rabbits with extensive pulmonary granulomas exhibited inhibition of migration (auto-inhibition) in the absence of PPD. Granulomatous cells exhibiting auto-inhibition showed a tendency to escape both auto-inhibition and PPD-induced inhibition. Some BCG-immune sera potentiated PPD-induced inhibition, whereas other BCG-immune sera exhibited a tendency to relieve the auto-inhibitory response of granulomatous cells. Supernatant fluids obtained from granulomatous cells incubated with PPD inhibited the migration of normal alveolar cells. The possible role of the migration-inhibition response in granuloma formation is discussed.