Expression of TLR2 and TLR4 in lesions of patients with tegumentary american leishmaniasis

Abstract

SUMMARYObjectives: The aim of this study was to describe the pattern of expression of Toll-like receptor 2 (TLR2) and Toll-like receptor 4 (TLR4) in skin biopsies of patients with American tegumentary leishmaniasis (ATL) caused by Leishmania braziliensis. Methods: This prospective study evaluated 12 patients with ATL caused by Leishmania braziliensis confirmed by polymerase chain reaction. Immunohistochemistry was performed to determine the expression of TLR2 and TLR4. The number of NK cells, dendritic cells and macrophages in the tissue were calculated. The cytokine expression was determined using the anti-TNF-α, anti-IFN-γ, anti-IL-1 and anti-IL-6. Double immunostaining reactions were used to determine the cell expressing TLR2 and TLR4. Results: The numbers of cells expressing TLR2 and TLR4 were 145.48 ± 82.46 cell/mm 2 and 3.26 ± 4.11 cell/mm 2 respectively (p < 0.05). There was no correlation of TLR2 and TLR4 with the amount of cytokines and the number of NK cells, dendritic cells or macrophages. The double immunostaining revealed that TLR2 was expressed by macrophages. Conclusion: In human cutaneous leishmaniasis caused by Leishmania braziliensis, TLR2 is the most common TLR expressed during active disease, mainly by macrophages although without correlation with the amount of cytokines and number of cells.

Dog skin parasite load, TLR‐2, IL‐10 and TNF‐α expression and infectiousness

“…The activation of Toll‐like receptors has recently emerged as an important step in determining the type of immune response and therefore may have an impact on the development of the disease . Toll‐like receptors are capable of recognizing lipophosphoglycan molecules present in the surface of the flagellated promastigote form of the protozoon, resulting in intracellular reactions responsible for the production of pro‐inflammatory and anti‐inflammatory cytokines .…”

“…4,5 On the other hand, sick dogs often exhibit predominance of a Type 2 profile, with expression of transforming growth factor beta (TGFβ) and interleukin 10 (IL-10), as well as an exacerbated humoral immune response due to B lymphocyte proliferation. 6 The activation of Toll-like receptors has recently emerged as an important step in determining the type of immune response [7][8][9] and therefore may have an impact on the development of the disease. 10,11 Toll-like receptors are capable of recognizing lipophosphoglycan molecules present in the surface of the flagellated promastigote form of the protozoon, 12 resulting in intracellular reactions responsible for the production of pro-inflammatory and anti-inflammatory cytokines.…”

Recombinant Leishmania major lipophosphoglycan 3 activates human T-lymphocytes via TLR2-independent pathway

“…From this it can be concluded that the stimulation of IFN production induced in the T-cells by LPG3 and the NT fragment was via a TLR2-independent pathway(s). Such an outcome would appear to conflict with recent studies that demonstrated that TLR2 and TLR4 were involved in the recognition of L. major (Tuon et al, 2012). Moreover, de Veer et al (2003) showed that TLR2-deficient mice infected with L. major had an increased numbers of lesions.…”

Do You See What I See: Recognition of Protozoan Parasites by Toll-Like Receptors

“…A far as a role for TLRs in sensing Leishmania infection in humans, expression of TLR-2, TLR-4 and TLR-9 have been shown within lesions of patients infected with Leishmania brasiliensis [118, 119]. Also, Mϕs isolated from the blood of patients with non-healing cutaneous L. major lesions were shown to express reduced amounts of TLR-2 and -4 compared to Mϕs from patients who were capable of healing their lesions [120], suggesting a role for TLR-2 and -4 in the outcome of cutaneous leishmaniasis.…”