Early response of lymphatic system to experimental infection with Mycobacterium kansasii and Mycobacterium...

Weight, cellularity and metabolic activity (nucleolar test) of draining and contralateral popliteal lymph nodes were studied in groups of guinea pigs infected intratarsally in right hind limb with Mycobacterium kansasii (2.4 x 10(6) viable units) and Mycobacterium scrofulaceum (3.4 x 10(6) viable units) species and examined 1, 3, 7 and 14 days after inoculation. Time-related differences and inter-group differences in cellularity and per cent of active lymphocytes were statistically analyzed by paired t-test. Experimental animals infected with the two mycobacterial species showed at all time intervals a significant increase in weight, cellularity and per cent of active lymphocytes in draining lymph nodes as compared to contralateral nodes and to control values. Infection with M. kansasii produced a more significant increase in all the parameters studied than inoculation with M. scrofulaceum. These differences are in agreement with the different pathogenic activity of these two species of the potentially pathogenic mycobacteria. Early activation of lymphatic tissues occurring within the first 24 hours after inoculation results from the action of some cellular immunity mediators is released already at the early phases of lymphocyte-antigen interaction.