Effect of pretreatment with Bacillus Calmette-Guerin on the course of a Listeria monocytogenes infection in normal and congenitally athymic (nude) mice.

The effect of pretreatment with BCG on the course of a Listeria monomcytogenes infection was studied in nu/nu mice and in their heterozygous littermates (+/nu). First, evidence was presented that the nu/nu mice used lacked functional T cells, since BCG treatment resulted only in skin reactivity to tuberculin in +/nu mice and not in nu/nu mice. Acquired resistance to Listeria (based on lower spleen counts) was only obtained in BCG pretreated +/nu mice. Evidence was presented that BCG pretreatment in nu/nu mice failed to increase non-specific resistance, both in terms of spleen counts and survival rate. These results seem to imply that functional T cells are required for this type of non-specific resistance to heterologous antigens. In this connection attention has been drawn to the possible implication of BCG treatment in man.