RESUMO
We evaluated the adoptive transfer of DCs on Leishmania (L.) mexicana-infected neonatal BALB/c mice. DCs were isolated and purified from the spleens of the following donor groups: a) Adult BALB/c mice infected during adulthood with L. (L) mexicana; b) Adult BALB/c mice infected during neonatal life; c) Healthy neonatal BALB/c mice; d) Healthy adult BALB/c mice. A neonatal model of infection, generated after inoculation with 5 × 105 promastigotes of L. (L) mexicana, was used as the infection control group. Sixteen hours after intraperitoneal transfer of DCs (1 × 103, 1 × 105, or 1 × 106 cells/ml), neonatal recipient BALB/c mice were infected. The adoptive transfer of DCs diminished disease progression in neonatal mice. This reduction depends on the quantity and provenance of transferred DCs, since the effect was more evident with high numbers of DCs from adult mice infected during adulthood and healthy neonatal mice. Protection was significantly reduced in animals receiving DCs from healthy adult mice but it was absent in mice receiving DCs from adult mice infected during neonatal life. These results suggest that genetic susceptibility to Leishmania infection can be modified during neonatal life, and that the period of life when antigens are encountered is crucial in influencing the capacity of DCs to induce resistance or tolerance.
RESUMO
We characterized key leukocyte immunophenotypes in the liver and spleen of naturally infected dogs from an area in Venezuela endemic for leishmaniasis. Dogs were classified as symptomatic or asymptomatic after serologic and physical analysis. Symptomatic dogs showed a higher parasite burden in the liver and spleen than asymptomatic dogs. The livers of asymptomatic dogs showed an effective immunity with well-organized granulomas walling off parasites in an environment of central memory CD44(lo), CD45RO(hi), activated effector CD44(hi), and CD45RO(hi) T cells. These granulomas also had many major histocompatibility class II+ cells and CD11c+ dendritic cells, and cells expressing CD18 and CD44. In contrast, symptomatic livers showed a non-organized and non-effective infiltrate composed of T cells and heavily parasitized Kupffer cells and a diminished expression of activation molecules. In the spleen, the immune responses of symptomatic and asymptomatic dogs were very similar. The results showed a distinct immune response against Leishmania chagasi in target organs.
Assuntos
Doenças do Cão/imunologia , Leishmaniose Visceral/veterinária , Fígado/imunologia , Baço/imunologia , Animais , Doenças do Cão/parasitologia , Doenças do Cão/fisiopatologia , Cães , Feminino , Imunofenotipagem , Leishmania , Leishmaniose Visceral/imunologia , Leishmaniose Visceral/parasitologia , Masculino , Especificidade de Órgãos , Linfócitos T/imunologiaRESUMO
La leishmaniasis cutánea americana (LCA) presenta varias manifestaciones clínicas e inmunitarias: La leishmaniasis cutánea localizada (LCL), cuya respuesta inmunitaria es tipo Th1, la leishmaniasis cutánea difusa (LCD) con una respuesta Th2, y la leishmaniasis cutánea intermedia (LCI) cuya respuesta inmunitaria es exacerbada con un patrón mixto de citocinas. Se ha demostrado la importancia de los receptores tipo toll (TLR) en la respuesta inmunitaria frente a Leishmania promoviendo la transcripción y síntesis de citocinas inflamatorias. El reconocimiento de componentes del parásito por los TLRs activa a macrófagos, células dendríticas y células NK. En este estudio, evaluamos la presencia TLR2, TLR4, TLR9 y células tipo NK (NK y NKT CD56+) en las lesiones de pacientes con LCL, LCI y LCD mediante inmunocitoquímica. Las lesiones de LCL y LCD mostraron una alta densidad de células TLR2 y TLR4+ con respecto a LCI, mientras que LCD mostró una mayor densidad de células TLR9+. Se observó también la expresión de TLR2 en los queratinocitos y el TLR9 se localizó en el interior de los macrófagos infectados asociado con los parásitos. La densidad de células CD56+ fue mayor en LCL en comparación con LCI y LCD. Los resultados demuestran la participación de los TLR2, 4 y 9 en la respuesta inmunitaria durante la LCA, mostrando evidencia del reconocimiento del parásito por TLR9 y una mayor densidad de células NK en LCL que se puede asociar a la respuesta Th1 que prevalece en estos pacientes.
American cutaneous leishmaniasis (ACL) has several clinical and immunological manifestations: localized cutaneous leishmaniasis (LCL) that produces a Th1 immune response, diffuse cutaneous leishmaniasis (DCL) that produces a Th2 response, and intermediate cutaneous leishmaniasis (ICL) that promotes an exacerbated immune response with a mixed pattern of cytokines. The importance of toll-like receptors (TLRs) to the immune response has been demonstrated against Leishmania, as these promote the transcription and synthesis of inflammatory cytokines. Parasite components are recognized by TLRs leading to the activation of macrophages, dendritic cells and NK cells. In this study, we evaluated the presence of TLR2, TLR4, TLR9 and NK/NKT CD56+ cells by immunocytochemistry in the lesions of patients with LCL, ICL and DCL. LCL and DCL lesions showed higher densities of TLR2 and TLR4 cells than ICL, while DCL showed an increase in TLR9 + cell density. The expression of TLR2 in keratinocytes was also observed, and TLR9 was located inside the infected macrophages in contact with the parasites. NK cell density was higher in LCL compared with ICL and DCL. These results demonstrate the participation of TLR2, 4 and 9 in the immune response during ACL, and show evidence of parasite recognition by TLR9 and increased CD56+ cell density in LCL associated with the Th1 response which prevails in these patients.
RESUMO
En el presente estudio se caracterizó el patrón de citocinas del bazo e hígado de perros infectados en forma natural por Leishmania infantum (chagasi) provenientes del estado Nueva Esparta, Venezuela. Los perros fueron clasificados como sintomáticos y asintomáticos considerando tres signos principales de esta patología como hepatoesplenomegalia, caquexia y onicogrifosis. Muestras de hígado y bazo fueron tomadas para evaluar carga parasitaria y la expresión de citocinas y quimiocinas por inmunohistoquímica. En los perros sintomáticos se observó una mayor carga parasitaria tanto en el hígado como en bazo. En el bazo se observó una densidad de células positivas para interferón gamma (IFN-g), interlucinas (IL-12, IL-10, IL-4, IL-8) y Proteína 1 quimioatrayente de monocito (MCP-1), similar en perros asintomáticos y sintomáticos. Mientras que en el hígado la evaluación de las citocinas IFN-g, IL-12, IL-10 IL-8 y MCP-1, mostró una tendencia al aumento en el grupo de perros sintomáticos, con incremento significativo de las células IL-4+ en los perros sintomáticos, con respecto a los asintomáticos. La densidad de células IL-4+ en el hígado se correlacionó positivamente con la hepatomegalia. Al cuantificar las concentraciones séricas de la quimiocina Proteina 1 alfa inflamatoria de macrófago (MIP-1a) se observó una alta producción en los perros asintomáticos. Estos resultados confirman laexistencia de una respuesta órgano-especifica frente a L. infantum (chagasi), del tipo T cooperador 2 (Th2) en el hígado de los perros sintomáticos, caracterizada por un marcado predominio de IL-4 sobre IFN-g e IL-12. La elevada producción de IL-4 fue directamente relacionada con la hepatomegalia.
In the present study, we characterized the cytokine pattern in the spleen and liver of naturally infected dogs with Leishmania infantum (chagasi) from the Nueva Esparta state of Venezuela. The dogs were classified as symptomatic and asymptomatic considering three main signs of this disease: hepatosplenomegalia, cachexia and onichogriphosis. Tissue samples from liver and spleen were taken to evaluate parasite load, cytokines and chemokines expression by immunohistochemistry. In symptomatic dogs, a higher parasitic load was observed in the liver and spleen as compared to asymptomatic dogs. In the spleen, the density of gamma interferón (IFN-g), interleukins (IL-12, IL-10, IL-4, IL-8) and Monocyte Chemoattractant Protein-1 (MCP-1), it was similar between asymptomatic and symptomatic dogs. Whereas, in the liver IFN-g, IL-12, IL-10 IL-8 and MCP-1 showed a tendency to increase in symptomatic dogs, with a significant increment of IL-4 + cells. In the liver, the density of IL-4+ cells was positively correlated with hepatomegaly. In addition, higher concentrations of Macrophage inflammatory protein 1 alpha (MIP-1a) were observed in the serum of asymptomatic than in symptomatic dogs. These results corroborate the existence of an organ-specific immune respose against L. infantum (chagasi), with a T helper 2 (Th2) immune response in the liver of symptomatic dogs, with prevalence of IL-4 over IFN-g and IL-12. The high production of IL-4 is directly related with hepatomegalia.