T cell responses to crude and defined leishmanial antigens in patients from the Lower Amazon region of Brazil infected with different species of Leishmania of the subgenera Leishmania and Viannia

Abstract

Amazonian localized cutaneous leishmaniasis (LCL) is caused by parasites of the subgenera Leishmania and Viannia. Respectively, these parasites may cause diffuse cutaneous leishmaniasis (DCL) and mucocutaneous leishmaniasis (MCL). This, together with differing skin test responses, suggests some species-specificity in cell mediated immunity. In this study, T cell responses (proliferative and interferon-gamma) to crude and defined antigens were examined in paired samples pre and post chemotherapy. Untreated L. (L.) amazonensis LCL patients showed lower responses to crude leishmanial antigens than the L. (V.) spp. group. L. (V.) braziliensis antigen was a more potent stimulator of T cell responses than L. (L.) amazonensis antigen in all patient groups. Few positive responses were seen to the L. (L.) amazonensis glycoprotein GP46. A substantial proportion of LCL patients did respond to the L. (L.) pifanoi amastigote antigens A2, and the surface membrane glycoprotein P8. DCL patients were poor responders to all leishmanial antigens, except GP46. In contrast, MCL patients were good responders to all antigens except GP46 and A2. A significant rise in the response to P8 and A2 antigen was seen post treatment across all LCL and MCL patients, indicating that these antigens might provide suitable vaccine candidates.

Novas evidências sobre o valor diagnóstico da reação de imunofluorescência indireta e reação intradérmica de hipersensibilidade tardia na infecção humana por Leishmania (L.) infantum chagasi na Amazônia, Brasil

“…The land is flooded twice a day by the Tocantins River. Thus, the climate and the environmental conditions in this area are very similar to those described in another study conducted in the Municipality of Barcarena, Pará State, located approximately 150 km from this area, where the dynamics of human L. (L.) i. chagasi transmission was previously 28 studied .…”

“…We designed the current study in a similar manner as 28 our two previous studies; one has already been published 29 and the other was accepted for publication .…”

“…For MST, weak skin reactions (5-8 mm) received +, moderate reactions (9-12 mm) ++, strong reactions (13-15 mm) +++, and exacerbated reactions (16 mm) ++++. Thus, we assumed that serological reactions from a titer designation of 80 (IgG) and skin reactions forming indurations ³ 5 mm in diameter were considered positive 23,31,28 cut-off points for IFT and MST, respectively . Therefore, when combining the clinical state of the infected individuals with the semi-quantitative scale of the IFT and MST results, we could identify the following immunological profiles in the clinical infection groups: AI (MST+/++++ and IFT-), SI (=AVL) and SOI with the same immunological profile (MST-and IFT+++/++++), SRI (MST+/++++, and 11,29 IFT+/++) and III (MST-and IFT+/++) .…”

“…The implementation of MST followed the same technical steps described in other studies for the diagnosis of American 31,28 cutaneous leishmaniasis (ACL) . Notwithstanding, considering that this study area has similar epidemiological characteristics that suggest the possibility of ACL transmission, we used a highly specific antigen for AVL, generated from promastigote forms of a stationary phase culture ( amazonensis.…”

Cytokine profile in Montenegro skin test of patients with localized cutaneous and mucocutaneous leishmaniasis

“…The Th1 response in MCL is more intense than in LCL, as demonstrated by the IFN-gamma and IL-2 that are observed at high proportions in vitro and in situ, and an exacerbated lymphoproliferative response to Leishmania antigen in vitro 4,6,31 .…”