Measurement of resistance to experimental tuberculosis in mice.

NCS mice were found to be susceptible to a hyperacute form of disease induced by injection of relatively large doses of Mycobacterium tuberculosis. Susceptibility to this type of disease was conditioned by the sex, age, and dietary history of the animals. Unlike the more usual response of mice to mycobacterial disease, these conditions affected primarily the relative occurrence of early-acute deaths rather than average survival time. Resistance to this form of disease was increased by previous exposure of the animals to Gram-negative bacteria, to their endotoxin, or to various preparations of killed mycobacterial cells.