RESUMO
Cellular immune responses directed against protozoan parasites are key for controlling pathogen replication and disease resolution. However, an uncontrolled, or improperly controlled, response can be deleterious to the host in terms of both allowing for the establishment of pathology, as well as less effective establishment of memory responses. Human cutaneous leishmaniasis is a disease caused by the infection with Leishmania spp. following a bite from the sandfly, the natural vector of this disease. Tens of millions worldwide are currently infected with Leishmania and no effective vaccines have been developed to date. In the face of the complexity presented by the interaction between a host (humans) with the parasite, Leishmania, and the fact that this parasite is inoculated by another complex, biologically active, vector, the sandfly, it is clearly important to study the immunoregulatory mechanisms that are induced in humans naturally infected by this parasite if we hope to develop effective vaccines and immunotherapeutic treatments in the future. Our laboratory has focused over the years on the study of the local and systemic T cell response during the first episode of cutaneous leishmaniasis suffered by individuals before they undergo antimony treatment. The goal of this review is to briefly outline our findings with hopes of putting our most recent studies concerning the dichotomy between alpha/beta TCR and gamma/delta TCR expressing, CD4-CD8- (double negative-DN) T cells in the context of a balanced immune response against Leishmania and to discuss the implications of these findings toward our understanding of human leishmaniasis.
Assuntos
Antígenos CD4/efeitos dos fármacos , Antígenos CD8/efeitos dos fármacos , Leishmania , Leishmaniose Cutânea/imunologia , Subpopulações de Linfócitos T/imunologia , Animais , Arginase/imunologia , Previsões , Humanos , Receptores de Antígenos de Linfócitos T alfa-beta/imunologia , Receptores de Antígenos de Linfócitos T gama-delta/imunologiaRESUMO
Enfuvirtide (T-20) is the first approved HIV-1 entry into cells' inhibitor. It is a peptide with an amino acid sequence analogue to HR2 region of the viral surface glycoprotein gp41. Its mechanism of action is the competitive binding to HR1 region of the gp41, preventing the interaction between HR1 and HR2 and impeding the conformational changes in gp41 necessary for fusion of the virus with the cell. Its application is by subcutaneous injection. The main clinical trials of enfuvirtide (TORO 1 and 2) were performed in HIV-infected patients with virological failure, high antiretroviral experience and highly resistant viral isolates. Those trials showed that the addition of enfuvirtide to an optimized HAART (chosen with a resistance test) provided better results than HAART alone, measured by drop in viral load and immunologic benefit. The best results were observed in the subgroup of patients with more useful drugs in HAART (according to the information of the resistance test), a lower viral load, and a higher CD4 cell count at baseline. The most important adverse event is the production of injection drug hypersensitivity reaction in 98% of patients. The high cost is compensated by a reduction in costs derived from admissions.
Assuntos
Proteína gp41 do Envelope de HIV/uso terapêutico , Inibidores da Fusão de HIV/uso terapêutico , Infecções por HIV/tratamento farmacológico , HIV-1 , Fragmentos de Peptídeos/uso terapêutico , Terapia Antirretroviral de Alta Atividade , Antígenos CD4/efeitos dos fármacos , Contagem de Linfócito CD4 , Farmacorresistência Viral , Enfuvirtida , Proteína gp41 do Envelope de HIV/efeitos adversos , Inibidores da Fusão de HIV/efeitos adversos , Infecções por HIV/virologia , HIV-1/efeitos dos fármacos , Humanos , Fragmentos de Peptídeos/efeitos adversos , Falha de Tratamento , Carga ViralRESUMO
Enfuvirtide (antes T-20) es el primer inhibidor de la entrada a la célula del HIV-1 en ser aprobado. Es un péptido análogo de la porción HR2 de la glucoproteína de superficie viral gp41. Su mecanismo de acción consiste en la unión competitiva a la porción HR1 de la gp41 para impedir los cambios conformacionales del complejo gp41-gp120 tras la unión del HIV-1 a los receptores celulares, impidiendo así el acercamiento y posterior fusión entre el virus y la célula. Se aplica por vía subcutánea. Los resultados de los principales estudios clínicos (TORO 1 y 2) llevados a cabo en pacientes con fallo virológico, tratamientos previos con antirretrovirales y portadores de cepas virales altamente resistentes, mostraron que quienes recibieron enfuvirtide + HAART optimizado, elegido mediante un test de resistencia, presentaron mayores beneficios que quienes sólo recibieron HAART optimizado, en términos de mejor recuperación inmune y mayor descenso de la carga viral de HIV. Los mejores resultados se observaron en el subgrupo de pacientes con más drogas útiles en el HAART según el test de resistencia, una menor carga viral de HIV y un mayor recuento de linfocitos CD4 basales. El principal efecto adverso es el desarrollo de lesiones por hipersensibilidad en los sitios de aplicación. El alto costo de enfuvirtide se vio compensado por una reducción en los costos de internación.(AU)
Enfuvirtide (T-20) is the first approved HIV-1 entry into cells inhibitor. It is a peptide with an amino acid sequence analogue to HR2 region of the viral surface glycoprotein gp41. Its mechanism of action is the competitive binding to HR1 region of the gp41, preventing the interaction between HR1 and HR2 and impeding the conformational changes in gp41 necessary for fusion of the virus with the cell. Its application is by subcutaneous injection. The main clinical trials of enfuvirtide (TORO 1 and 2) were performed in HIV-infected patients with virological failure, high antiretroviral experience and highly resistant viral isolates. Those trials showed that the addition of enfuvirtide to an optimized HAART (chosen with a resistance test) provided better results than HAART alone, measured by drop in viral load and immunologic benefit. The best results were observed in the subgroup of patients with more useful drugs in HAART (according to the information of the resistance test), a lower viral load, and a higher CD4 cell count at baseline. The most important adverse event is the production of injection drug hypersensitivity reaction in 98% of patients. The high cost is compensated by a reduction in costs derived from admissions.(AU)
Assuntos
Humanos , Fragmentos de Peptídeos/uso terapêutico , Proteína gp41 do Envelope de HIV/uso terapêutico , Inibidores da Fusão de HIV/uso terapêutico , Infecções por HIV/tratamento farmacológico , HIV-1 , Fragmentos de Peptídeos/administração & dosagem , Fragmentos de Peptídeos/efeitos adversos , Proteína gp41 do Envelope de HIV/administração & dosagem , Proteína gp41 do Envelope de HIV/efeitos adversos , Inibidores da Fusão de HIV/administração & dosagem , Inibidores da Fusão de HIV/efeitos adversos , Infecções por HIV/virologia , HIV-1/efeitos dos fármacos , Farmacorresistência Viral , Contagem de Linfócito CD4 , Terapia Antirretroviral de Alta Atividade , Carga Viral , Falha de Tratamento , Antígenos CD4/efeitos dos fármacosRESUMO
Alterations in immune function are associated with major depression and have been related to changes in endocrine function. We investigated whether alterations in immune function were associated with altered basal hypothalamic-pituitary-adrenal (HPA) function (salivary cortisol) and lymphocyte sensitivity to dexamethasone (DEX) intake (1 mg PO). The latter was explored by comparing the impact of DEX-induced changes on peripheral lymphocyte redistribution and expression of adhesion molecules (beta2 integrins and L-selectin). The study included 36 inpatients with treatment-resistant major depression (unipolar subtype) and 31 matched healthy controls. The dexamethasone suppression test (DST) was carried out and used to classify 10 patients as HPA axis non-suppressors. The latter presented significantly higher post-DEX salivary cortisol levels than DST suppressors, 82.0 vs. 8.9 nM l(-1) h(-1). No differences in basal salivary cortisol levels were found between patients and controls. Changes in cell redistribution (CD4(+), CD8(+), CD19(+), CD56(+) and HLADR(+) cells) after DEX administration were more prominent in controls than in patients, but the effects of DEX varied dependent on whether patients exhibited DEX-induced suppression of cortisol secretion. Glucocorticoid-induced suppression of adhesion molecule expression was also generally less marked in patients than controls. Our data indicate that alterations in immune function and steroid regulation associated with depression are not related to elevated basal levels of cortisol and further suggest that lymphocyte steroid resistance is associated with drug-resistant depression.