Evolution of lymphocyte populations in armadillos (Dasypus novemcinctus) inoculated with M. leprae.

In human leprosy patients there are changes in the percentages of T and B lymphocytes in peripheral blood, and there is a correlation with the clinical characteristics or manifestations of the disease. These phenomena still require clarification regarding the triggering mechanism involved that may lead to one or the other clinical entities. Much has yet to be learned about the intricacies of whether the changes in subpopulations of T and B lymphocytes are a causative factor or an effect attributable to the microorganism itself. The armadillo is an excellent animal model to study how Mycobacterium leprae spread, turning into an established infection. The application of modifications in percentages of the subpopulations of B and T lymphocytes in armadillos may well lead to extrapolation of the results obtained in this animal model in an attempt to be able to manipulate the 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 groups of armadillos: five randomly chosen animals formed the control group and 11 armadillos were inoculated with M. leprae obtained from a human leproma at the onset of the 12-month period of the study. Of the 11 randomly selected armadillos that were inoculated, only five developed an active and disseminated infection. The percentage of rosette-forming cells did not show statistically significant variations during the first 6 months of the study. However, at months 8 and 12 a significant increment in this parameter was observed (p < 0.05) in the animals with active infection. In regard to the variations in the numbers of sIgM+ cells, significant changes occurred in the armadillos with active infection at month 2. However, results returned to normal and no changes were seen at later times. No significant changes occurred in the group of animals inoculated but not developing active infection compared with the other groups. The results are considered sufficiently interesting to encourage further study on the cell-mediated immune system of the armadillo and the changes that occur during the development and dissemination of an inoculated infection with M. leprae. Since this mammal is of great value as an effective animal model in the experimental research of M. leprae, there is an urgent need to obtain, as quickly as possible, a thorough understanding of the cellular branch of its immune system and, thereby, be in a position to extrapolate immune modulation to benefit human leprosy patients.

Immunomodulation of human T cell responses with receptor selective enkephalins.

The delta-opioid receptor selective [2-D-penicillamine-5-D-penicillamine] enkephalin (DPDPE) and the mu receptor selective Tyr-D-Orn-Phe-Asp-NH2 (TOPA) were found respectively, to have marked immunostimulant and immunosuppressant activities in both normal subjects and patients suffering from leprosy and tuberculosis. Antigen specific lymphoproliferation and numbers of rosette forming T cells were significantly (P < 0.05) enhanced on in vitro treatment with Met-enkephalin. This was further increased (P < 0.001) in the presence of the delta selective DPDPE. In contrast, treatment with mu selective TOPA inhibited lymphoproliferation substantially (P < 0.01) and rosette formation to a lesser extent.

Flow cytometric analysis of CD2 modulation on human peripheral blood T lymphocytes by Dharmendra preparation of Mycobacterium leprae.

It has been reported previously that Mycobacterium leprae modulated CD2 on human peripheral blood T lymphocytes and that this modulation was accompanied by a marked reduction in the proliferative response of these cells to mitogens and antigens. In this study, we report that treatment of peripheral blood mononuclear cells from healthy individuals with Dharmendra preparation of M. leprae inhibited their ability to form rosettes with sheep red blood cells. Flow cytometric analysis of Dharmendra lepromin-treated cells showed that, in addition to CD2, CD4 and CD8 were modulated while the surface expression of CD3 was not affected. The specificity of CD2 modulation was confirmed by similar effects of Dharmendra lepromin on thymocytes and lymph node cells from human CD2 transgenic mice. The modulatory effect of Dharmendra lepromin was not observed at lower temperatures. Dharmendra lepromin treatment of activated T cells resulted in reduced binding of monoclonal antibodies to IL-2R and D66 epitope of CD2. The modulatory effects were not observed with Dharmendra preparation of BCG or other preparations of M. leprae. Our results indicate that certain M. leprae factor(s) specifically modulate(s) CD2, CD4, CD8 and IL-2R but not CD3 on T lymphocytes. The suppressive effect of Dharmendra lepromin on the T-cell proliferative response reported earlier may be explained by its modulatory effect on a number of T-cell surface molecules.

Immunologic defects in leprosy patients. I. Evidence of immune aberration of suppressor-T lymphocytes in lepromatous leprosy.

Immunoregulation in various types of leprosy patients was evaluated in vitro using peripheral blood mononuclear leukocytes (PBML) stimulated with phytohemagglutinin-P (PHA-P) or concanavalin A (ConA) for a cell-mediated immune (CMI) assay or pokeweed mitogen (PWM) for a humoral-mediated immune (HMI) assay. The immune responses were evaluated by a lymphocyte transformation test (LTT) and lymphocyte-mediated cytotoxicity (LMC) for the immunoregulation of CMI, and a reverse hemolytic plaque assay for measuring the plaque-forming cells (PFC) and a sandwich ELISA for measuring IgG concentrations for the immunoregulation of HMI. In LTT with PHA-P or ConA, the mean of the normal controls was not significantly different from the means of the untreated LL, BL, BB, BT, and TT leprosy patients. However, a wide variation of LTT results from BT to LL patients was noted: the LTT results of TT patients and normal controls were less variable. A similar pattern of immune responses was noted when studied by LMC in untreated LL, BL, BB, BT, and TT leprosy patients and normal controls. When the untreated patients and normal controls were studied for PFC, using PBML stimulated with PWM, a very similar pattern of PFC was obtained with the different types of leprosy patients. The immunoregulatory role of lymphocytes in leprosy patients was further evaluated by cell mixing cultures. ConA-stimulated PBML from lepromatous leprosy patients were mixed with normal PBML and then stimulated with PHA-P.(ABSTRACT TRUNCATED AT 250 WORDS)

T lymphocyte subpopulations in leprosy patients and their relation with circulating immune complexes.

The possible relationship between circulating immune complexes (CIC) and peripheral T lymphocyte populations was studied in thirteen active multibacillary leprosy (10 lepromatous--LL--and 3 borderline lepromatous--BL--) and 19 matched controls. Theophylline-resistant T cells (The-R, a lymphocyte subpopulation displaying helper activity on B cells) and total T cells were assessed by means of the E rosette technique, with and without previous theophylline incubation, 1h 37 degrees C, respectively. CIC were quantified by 125I-C1q binding test. Although leprosy patients showed a statistical non significant light depression in total T cells the remarkable variability in circulating levels of The-R T cells enabled us to separate them into two well delineated groups (in relation to this variable p less than 0.001) with no difference in age, sex and bacteriologic state: a) leprosy patients with The-R T cells proportionally conserved (6LL and 2BL); b) leprosy patients with The-R T cells proportionally depressed (4LL and 1BL). Patients belonging to the latter group showed the highest statistically significant levels of CIC. Even though we do not discard an unknown factor being responsible for our findings, we believe that this inverse relationship between elevated CIC and depressed The-R circulating T cells might be representing a lower helper activity on antibody synthesis intending to reduce its excessive production.

[Desoxyfructo-serotonin: its therapeutic effect in the treatment of leprosy]. / La desoxyfructo-serotonine: son effet thérapeutique dans le traitement de la lèpre.

Desoxyfructo-serotonin (DFS) has shown good results in clinical trials of LL patients. After clinical trials in Bamako (Mali) reported in three articles, clinical trials began in India, at Bombay. Acute toxicity tests done in Paris and chronic toxicity tests done in India had shown absence of side effects. This was also confirmed after pre-clinical pharmacology. In vitro tests show that DFS enhances cellular immune response. Receptors for anti-erythrocyte antibody on LL macrophages are demonstrated by erythrocyte rosetting. Infection with M. leprae markedly reduces rosetting. But in the presence of DFS this reduction in rosetting is not observed. Patient's peripheral blood lymphocytes, sensitised with leprosy antigen, show a low level of rosetting with patients' macrophages. DFS greatly enhances the lymphocyte-macrophage interaction. DFS has an important anti-stress activity. Gastric ulcer induced in rats by restraint were reduced by 40% (Mester et al.) and 50% (Das Neves). DFS increased the uptake of serotonin by LL patients platelets. HPLC studies were done to see the level of DFS in the plasma, in the serum and in the urine of LL patients and controls. We are synthetising new lyposoluble derivatives in order to make easier the penetration of DFS and a long time effect.

The alternative pathway of T cell activation: biology, pathophysiology, and perspectives for immunopharmacology.

The application of monoclonal antibodies and recombinant mediators to studies of T cell activation has led to a new concept regarding the central mechanisms underlying specific immune responses in man. Stimulation of human T cells to express their functional programs with regard to immunoregulatory activities and effector functions can be mediated through several distinct mechanisms or pathways. We report on the recently discovered T3-Ti antigen receptor independent mode of human T cell activation, namely, the T11-mediated "alternative pathway." Recent evidence supports the notion that this pathway plays an important role in the immune response in man and that failure to activate T cells through T11 is associated with immunodeficiency. The characterization of functional epitopes of the T11 molecule along with functional investigations on patients suffering from etiologically different cases of immunodeficiency provides important perspectives for future pharmacological interventions into the human immune system. It seems likely that immunologic disorders such as autoimmune disease and immunodeficiencies result from overamplification or blockades of the "alternative pathway of T cell activation" and that the T11 epitope represents a potential site for selective inhibition of the "alternative pathway of T cell activation," e.g., by means of synthetic peptide analogues. Conversely, high affinity ligands to the T11 epitope might be suitable for immunostimulation immunodeficiencies that result from circulating blocking factors of the LFA-3/T11 interaction.

[Lymphocyte imbalance in autoimmunity]. / La desregulación linfocitaria en autoinmunidad.

A subset of normal peripheral B lymphocytes expresses a T surface antigen recognized by monoclonal CD5. They form rosettes with mouse erythrocytes (MRBC). Other studies suggest that these B cells may have regulatory and helper properties. An expanded subset of lymphocytes forming MRBC was demonstrated in the peripheral blood of 31 Systemic Lupus Erythematosus (SLE) patients (14.4 +/- 2.8%) compared with normal controls (4.3 +/- 1.4%) and patients with tuberculosis (6.4 +/- 1.7%). Increased MRBC values correlated with disease severity. Investigation of cell surface antigen expression was attempted with enriched sedimented fractions using several monoclonal antibodies and immunofluorescent staining. Complete inhibition of MRBC formation was obtained with monoclonal antibodies against CD5, CD3 and CD8 while partial inhibition was observed with anti-Ia and no activity with CD4 and CD10 antibodies. Indirect evidence supports the concept that antilymphocyte antibodies cause T and B cell depletion and dysfunction. Sera from 12 patients with SLE and 28 with leprosy (LL) were analyzed for antibodies to lymphocytes in the microcytotoxicity assay: 87% of SLE and 57% of LL were positive. Lymphocytotoxic activity towards each cell type of a panel with 98 different HLA antigens was essentially the same and most sera were not specific for either T or B cells. Lymphocytotoxic sera from SLE and LL contained antibodies which inhibited MRBC formation.

La desregulación linfocitaria en autoinmunidad / Lymphocyte imbalance in autoimmunity

Una pequeña proporción de linfocitos B presente en ganglios y sangre periférica humana tiene la propiedad de formar rosetas con eritrocitos de ratón (RR) y expresar en la superficie de su membrana un antígeno de 67 Kda perteneciente a la serie T (Pan T) que es reconocido por el monoclonal CD5. Se valoró en sangre periférica de pacientes con Lupus Eritematoso Sistémico (LES) la capacidad de formar RR. Treinta y un LES tenían un valor de 14,4 + o - 2,8% que fue comparado con controles normales: 4,3 + o - 1,4 (p<0,001) y pacientes con tuberculosis activa 6,4 + o - 1,7%. La expansión de esta subpoblación en el LES correlacionó con la severidad de la enfermedad. En experimentos de inhibición obteniéndose efecto parcial con la y ninguna actividad con CD4 y CD10. Hay evidencias que apoyan el concepto de que los anticuerpos antilinfocitarios producirían disfunción y depleción específica de subpoblaciones T y B linfocitarias. Los sueros de 12 pacientes con LES y de 28 con lepra lepromatosa (LL) fueron investigados para la presencia de estos anticuerpos con el método de microcitotoxicidad. La mayoría de los sueros con LES (87%) y un 57% de los LL fueron positivos en este ensayo. No hubo diferencias en la actividad cuando se los enfrentó con un panel de 98 diferentes antígenos HLA y tampoco hubo reactividad selectiva para linfocitos T o B. En un sistema de inhibición de RR, tanto los sueros de LES como los de LL, mostraron interferencia en la formación de rosetas, lo que sugiere la presencia de...

La desregulación linfocitaria en autoinmunidad / Lymphocyte imbalance in autoimmunity

Una pequeña proporción de linfocitos B presente en ganglios y sangre periférica humana tiene la propiedad de formar rosetas con eritrocitos de ratón (RR) y expresar en la superficie de su membrana un antígeno de 67 Kda perteneciente a la serie T (Pan T) que es reconocido por el monoclonal CD5. Se valoró en sangre periférica de pacientes con Lupus Eritematoso Sistémico (LES) la capacidad de formar RR. Treinta y un LES tenían un valor de 14,4 + o - 2,8% que fue comparado con controles normales: 4,3 + o - 1,4 (p<0,001) y pacientes con tuberculosis activa 6,4 + o - 1,7%. La expansión de esta subpoblación en el LES correlacionó con la severidad de la enfermedad. En experimentos de inhibición obteniéndose efecto parcial con la y ninguna actividad con CD4 y CD10. Hay evidencias que apoyan el concepto de que los anticuerpos antilinfocitarios producirían disfunción y depleción específica de subpoblaciones T y B linfocitarias. Los sueros de 12 pacientes con LES y de 28 con lepra lepromatosa (LL) fueron investigados para la presencia de estos anticuerpos con el método de microcitotoxicidad. La mayoría de los sueros con LES (87%) y un 57% de los LL fueron positivos en este ensayo. No hubo diferencias en la actividad cuando se los enfrentó con un panel de 98 diferentes antígenos HLA y tampoco hubo reactividad selectiva para linfocitos T o B. En un sistema de inhibición de RR, tanto los sueros de LES como los de LL, mostraron interferencia en la formación de rosetas, lo que sugiere la presencia de... (AU)

T and B cells in borderline (BB) leprosy.

The response to standard Dharmendra lepromin and the circulating T, B cell numbers in the peripheral blood were quantitated in 15 patients with Borderline (BB) Leprosy. On the basis of lepromin response, the patients fall into three groups (a) negative (b) +/- reaction (c) rarely positive. No significant difference in the numbers of E-rosette and EAC rosette forming cells was observed in the BB patients in comparison to controls.

Accessory cell function of cells isolated from Mycobacterium leprae-induced granulomas.

The large cells from Mycobacterium leprae-induced granulomas in guinea pig lymph nodes were separated by Percoll discontinuous density gradient centrifugation and on a fluorescence-activated cell sorter (FACS) using cross-reacting monoclonal antibody to human MHC Class II antigens. Large Percoll-separated cells (83% Class II antigen positive and 52% macrophage-specific antigen positive) and FACS-separated cells are able to act as antigen-presenting cells for T-cell proliferation to PPD. In previous studies, macrophage antigen-positive cells consistently failed to act as accessory cells. This indicates that there is a population of accessory cells which are macrophage antigen negative and MHC Class II antigen positive present in these M. leprae-induced granulomas.

Immunologic aspects of leprosy.

Twenty seven cases of leprosy from Egypt were examined. Monocytes were found to be high in peripheral blood in lepromatous cases. The percentage of small lymphocytes in blood was increased in tuberculoid patients. The immunoglobulins were higher in all types of leprosy patients than in normal persons.