Macrophage spreading: inhibition in delayed hypersensitivity.

The capacity of peritoneal macrophages to spread was studied with cells of mice infected with Listeria monocytogenes and with cells of guinea pigs sensitized with BCG (bacille Calmette Guérin) vaccine or immunized with ovalbumin. In macrophages taken from animals having delayed hypersensitivity, this ability was markedly decreased by the presence of specific antigen for less than 1 hour. Such an effect was not observed in guinea pigs having only circulating antibodies.