Between the moderate LCL and the low-responsive ADCL, there is a weak, definite cellular hypersensitivity form known as borderline disseminated cutaneous leishmaniasis (BDCL), which has been shown to be lesser immunosuppressed than ADCL. On the other hand, L. (V.) braziliensis infection can cause not only LCL and BDCL but also the mucocutaneous leishmaniasis (MCL), the cellular hypersensitivity pole

of infection with a prominent Th1-type immune response (3). In this way, the ACL caused by these two Leishmania species presents a clinical–immunological spectrum where L. (L.) amazonensis shows selleck chemicals llc a tendency to lead infection to the anergic pole of cellular immune response, whereas L. (V.) braziliensis leads infection to the hypersensitivity pole of host cellular immune response (4). The diversity of clinical manifestations has mainly been associated www.selleckchem.com/products/ABT-888.html with antigenic differences of the different species of parasites (5), but also with the host immune-genetic background (6,7). The dendritic cells (DCs), both Langerhans cell (LC) and dermal dendritic cell (dDC), have been recognized as the main antigen-presenting cells in the skin with a capacity to capture antigen and migrate to the draining

lymph node for activation of a T-cell immune response (8). In this way, DCs seem to play a pivotal role in ACL immunopathogenesis once they represent the vehicle that promotes the first contact of Leishmania with the host immune response. PFKL Some studies have shown that in mice experimentally infected with L. (L.) major, the dDC and not LC as was previously postulated, were able to stimulate antigen-specific T-cell proliferation, suggesting that dDCs are crucial for initiating an appropriate and effective cellular immune response (9–11). In this way, Brewig et al (12). showed that proliferation of L.major-specific CD8+ T cells was reduced during the early

phase of the immune response in the absence of Langerin+ dDC and the impaired CD8+ T-cell response was because of the absence of Langerin+ dDC and not LCs, proposing a novel concept for the role of DCs in the immunopathogenesis of murine cutaneous leishmaniasis by L. major, where the priming of CD4+ T cells is mediated by Langerin-negative dDCs, while Langerin-positive dDCs are involved in the early priming of CD8+ T cells, leading to parasite elimination. Recently, using low-dose infection with L. major, Kautz-Neu et al (13). showed smaller lesions with decreased parasite loads, reduced number of CD4+ Foxp3+ T cells accompanied by increased IFN-γ production in mice depleted in Langerin+ DC; moreover, selective depletion of LC demonstrated that the absence of LC and not Langerin+ dDC was responsible for the reduction T reg cells and the enhanced Th1 response resulting in attenuated disease.