Quantitative studies on cell-mediated immunity in the pleural cavity of guinea-pigs.

Intrapleural injection of PPD into CFA-sensitised guinea-pigs produced a reaction having many of the characteristics of classical delayed hypersensitivity. Quantitative investigations of the time course of this reaction showed that it was typified by an initial delay in the onset of increased vascular permeability, which reached its peak between 12 and 18 hr. The cellular response in the pleural cavity followed a similar pattern, attaining maximum levels between 18 and 24 hr. Mononuclear cells dominated the reaction from 12 to 48 hr. The histological appearance of the lung tissue was also studied. Treatment with Cobra venom factor, a complement-depleting agent, failed to modify this reaction. Cyclic AMP levels were assayed for both the cellular and cell-free exudates.