[Delayed local reaction (DLR) after BCG vaccination in mice. I.--Description (author's transl]

Mice injected subcutaneously in the hind footpad with BCG vaccine subsequently develop a local reaction. This local reaction could be divided into three stages: a first characterized as an acute inflammatory reaction, a second as an active granulome formation, and a third as a chronic long lasting inflammatory reaction. The second stage is mainly formed by the appearance of a typical histiolymphocytic granuloma. The intensity of the delayed local reaction (DLR) is measured by the swelling of the injected footpad. This reaction does not occur after injection with irradiated (gamma or UV) BCG in normal mice, nor after injection of living BCG in Nude mice, indicating a T-cell immune response which develops during the in vivo multiplication of this intracellular bacteria. When the lymphoproliferation response in draining node was measured, a direct correlation was found with the intensity of the DLR, and the 125IUdR incorporation into DNA after injection of living BCG or after an irradiated BCG inoculation. The intensity and the rapidity of the onset of this DLR depend upon the dose of viable BCG inoculated in the mouse. When the DLR reached its peak, a linear dose relationship was observed in C57Bl/6 and in NCS mice.