DC-SIGN receptor is expressed by cells from cutaneous leishmaniasis lesions and differentially binds to Leishmania (Viannia) braziliensis and L. (Leishmania) amazonensis promastigotes

BACKGROUND Dendritic cells (DCs) specific intercellular adhesion molecule (ICAM)-3-grabbing non integrin receptor (DC-SIGN) binds to subgenera Leishmania promastigotes mediating its interaction with DC and neutrophils, potentially influencing the infection outcome. OBJECTIVES In this work, we investigated whether DC-SIGN receptor is expressed in cells from cutaneous leishmaniasis (CL) lesions as well as the in vitro binding pattern of Leishmania (Viannia) braziliensis (Lb) and L. (L.) amazonensis (La) promastigotes. METHODS DC-SIGN receptor was labeled by immunohistochemistry in cryopreserved CL tissue fragments. In vitro binding assay with CFSE-labeled Lb or La promastigotes and RAJI-transfecting cells expressing DC-SIGN (DC-SIGNPOS) or mock-transfected (DC-SIGNNEG) were monitored by flow cytometry at 2 h, 24 h and 48 h in co-culture. RESULTS In CL lesion infiltrate, DC-SIGNPOS cells were present in the dermis and near the epidermis. Both Lb and La bind to DC-SIGNPOS cells, while binding to DC-SIGNNEG was low. La showed precocious and higher affinity to DC-SIGNhi population than to DC-SIGNlow, while Lb binding was similar in these populations. CONCLUSION Our results demonstrate that DC-SIGN receptor is present in L. braziliensis CL lesions and interact with Lb promastigotes. Moreover, the differences in the binding pattern to Lb and La suggest DC-SIGN can influence in a difference way the intake of the parasites at the first hours after Leishmania infection. These results raise the hypothesis that DC-SIGN receptor could participate in the immunopathogenesis of American tegumentary leishmaniasis accounting for the differences in the outcome of the Leishmania spp. infection.

Immunological responsiveness to M. leprae and BCG antigens in 98 leprosy patients and their household contacts

The cellular immune response to M. leprae and BCG antigens was evaluated in 98 leprosy patients and 143 household contacts lacking clinical manifestation of the disease. The proliferative responses and release of Interferon-gamma by peripheral blood mononuclear cells were assessed and both patients and contacts were classified as low or high responders to M. leprae. The high responder contacts constitued 54.8% of the population analyzed, a three times higher proportion when compared to the controls, indicating the possible existence of active infection among them. The correlation coefficient between the immunological response to M. leprae and BCG was found to be higher within the contact group than in the patients, suggesting that cross-reactivity defense mechanisms against mycobacteria exist even before the onset of clinical detectable disease

Isolation and functional characterization of mononuclear phagocytes from human lepromatous lesions

Células inflamatórias presentes em lesöes Virchowianas humanas foram isoladas do tecido por um processo de digestäo enzimática. Elas foram mantidas em cultura por cerca de 5 dias e suas características morfológicas citoquímicas e funcionais foram descritas

Caracterizaçäo morfológica e funcional de células aderentes de baço de camundongo / Morphological and functional characterization of adherent splenic cells of mice

A separaçäo, caracterizaçäo e ensaio funcional das células inflamatórias presentes no local de lesäo têm se tornado imperiosos no estudo de diversas doenças. Através da utilizaçäo de métodos histoquímicos para esterase e fosfatase ácida, bem como do Teste de Fagocitose e da coloraçäo pelo Giemsa, realizados nas células esplénicas de dez camundongos, foi possível se caracterizar bem os componentes do Sistema Fagocítico Mononuclear e distinguir os outros tipos de células presentes, além de permitir a quantificaçäo diferencial das mesmas