INTERNATIONAL JOURNAL OF LEPROSY Volurnc 64. Numhcr 2 I'IIII~C~ I ~ I llir US A Evolution of Lymphocyte Populations in Armadillos (Dasypus novemcinctus) Inoculated with M. leprae l Fernando Guerra-Infante, Fausto Quesada-Pascual, Sergio Estrada-Parra, and Leopoldo Santos-Argumedo 2 Two distinct clinical presentations of My- cobacterium feprae infection in man corre- late with changes found in the T and B lym- phocytes of leprosy patients (6.9. 19). It is questionable if these alterations in the lym- phocyte characteristics are responsible for the variations in the clinical manirestations of tuberculoid leprosy (TL) or lcpromatous (LL) leprosy. Recent research has suggested that T lymphocytes from LL patients pro- duce an interleukin pattern in which interleukin-4 (IL-4), IL-5 and IL-10 are identifiable (I3* 21* 22). The preponderance of these interleukin moieties could explain the existence of anergy in the T-cell population and the exacerbation in the humoral re- sponses manifest in this specific type of pa- tients. Still needing explanation is whether the clinical entities are dependent on a pre- disposition of the infected individual to- ward one or the other type of lymphocyte response, or whether the microorganism per se is the determining factor. The answer is not clearly established since we still do not understand why T cells from LL patients generate a Th- 2 response while patients with TL give rise to a Th-1 interleukin pattern. T-cell supressor activity has been claimed to be responsible for the specific anergy seen among LL patients; CD8 T-cell clones taken from these patients generated a Th- 2 inter- leukin pattern (IL). Other factors, different than IL-4 or IL- I0 also have been claimed I Received for publication on 7 June 1995; accepted for publication in revised form on 5 December 1995. F. Guerra-Infante, M.Sc.; F. Qucsada-Pascual, M.Sc.; S. Estrada-Parra, Ph.D., Department of Im- munology, Escuela Nacional de Ciencias Biologicas, I.P.N., Prol. Carpio y Plan de Ayala, Mexico D F 1 1340, Mexico. L. Santos-Argumedo, Ph.D., Department of Cell Biology, Centro de Investigation y Estudios Avan- zados, I.P.N., Apartado Postal 14- 740, Mexico DF 07000, Mexico. Reprint requests to Dr. Santos-Argumedo at above address or FAX 52 - 5 - 747 - 7002 or e - mail san- tos@cell.cinvestav.mx to be responsible for this allergy ('). The role of IL- 12 (I5, 17) and the recognition of non- peptide antigens from M. feprae presented to T cells by human CD 1 b molecules should be evaluated in both tuberculoid and lep- romatous leprosy (I4) to analyze how they contributc to protection or anergy against M. feprac. To explain the proccss involved in the initial stages of M. feprae infection, an animal model may be quite helpful. Armadillos with an induced inrection with M. Ieprac (5v 16) develop a lepromatous-type infection, and spontaneous lcpromatous leprosy in these animals has been described ('9 20). There is little information concerning the immune responses related to AT. feprae infection in the nine - banded armadillo (Dasypus noven~cinctus). The data focus on antibody production (49 Is) and, presumably, changes in the cellular branch or immunity were omitted due to a lack of the required reagents. There are published results on specific lymphocyte markers for identification of these cell populations in arn~adillos. Rosette formation with sheep red blood cells (SKBC) (2p 3. 12), FC C3b receptors (2*3) and the presence of surface Ig (2. 3, are re- ported in the literature. Strangely, no con- trol comparisons between healthy versus in- oculated armadillos appears in these pub- lications. In the present study, particular interest has been given to the analysis of cellular changes in armadillos inoculated with M. feprae. Prior to this, a study on two lym- phocyte markers for lymphocytes Tram ar - madillos was performed: formation or ro- settes with SRUC and the identification of lymphocyte surface IgM (I2). Comparing these cell populations and the modifications that occur was begun many months before the initiation of this study, and provided a firm basis for the acquisition of internal controls of the parameters under investi- gation in these same armadillos.