[The tubercular process and antitubercular immunity in mice of different ages]

Experiments on "young" and "old" mice (aged, respectively, 2-4 and 22-24 months) infected with Mycobacterium tuberculosis, strain Bovinus-8, have revealed that in old mice the tuberculous process progresses at a faster rate than in "young" mice, which is manifested in "old" mice by their earlier death, more pronounced lesion of their internal organs and by a greater number of Mycobacterium colonies harvested after the inoculation of samples taken from their organs (after equal periods of incubation). In the process of the development of tuberculosis most immunity parameters are progressively suppressed, this suppression being more pronounced in the old animals and leading to a decrease in antibody-dependent cell cytotoxicity, the number of natural killer cells, the reaction of lymphocyte blast-transformation on PPD, cytotoxic effect on PPD-coated red blood cells, the synthesis of interleukin-1 and interleukin-2 after incubation with PPD, the titer of antituberculosis antibodies.