EVOLUTION OF LYMPHOCYTE POPULATIONS IN ARMADILLOS (DASYPUS-NOVEMCINCTUS) INOCULATED WITH M-LEPRAE

In human leprosy patients there are changes in the percentages of T an d B lymphocytes in peripheral blood, and there is a correlation with t he clinical characteristics or manifestations of the disease. These ph enomena still require clarification regarding the triggering mechanism involved that may lead to one or the other clinical entities. Much ha s yet to be learned about the intricacies of whether the changes in su bpopulations of T and B lymphocytes are a causative factor or an effec t attributable to the microorganism itself. The armadillo is an excell ent animal model to study how Mycobacterium leprae spread, turning int o an established infection. The application of modifications in percen tages of the subpopulations of B and T lymphocytes in armadillos may w ell lead to extrapolation of the results obtained this animal model in an attempt to be able to manipulate course of the disease in humans. The purpose of the study was to evaluate changes in the percentages of rosette-forming and sIgM+ mononuclear cells during a full year in gro ups of armadillos: five randomly chosen animals formed the control gro up and 11 armadillos were inoculated with M. leprae obtained from a hu man leproma at the onset of the 12-month period of the study. Of the 1 1 randomly selected armadillos that were inoculated, only five develop ed an active and disseminated infection. The percentage of rosette-for ming cells did not show statistically significant variations during th e first 6 months of the study. However, at months 8 and 12 a significa nt increment in this parameter was observed (p < 0.05) in the animals with active infection. In regard to the variations in the numbers of s IgM+ cells, significant changes occurred in the armadillos with active infection at month 2. However, results returned to normal and no chan ges were seen at later times. No significant changes occurred in the g roup of animals inoculated but not developing active infection compare d with the other groups. The results are considered sufficiently inter esting to encourage further study on the cell-mediated immune system o f the armadillo and the changes that occur during the development and dissemination of an inoculated infection with M. leprae. Since this ma mmal is of great value as an effective animal model in the experimenta l research of M. lep, ae, there is an urgent need to obtain, as quickl y as possible, a thorough understanding of the cellular branch of its immune system and, thereby, be in a position to extrapolate immune mod ulation to benefit human leprosy patients.