Macrophages participate in host protection and the disease pathology associated with <it>Leishmania braziliensis </it>infection

• Main Authors: Giudice Angela, Vendrame Célia, Bezerra Caroline, Carvalho Lucas P, Delavechia Thaís, Carvalho Edgar M, Bacellar Olívia
• Format: Article
• Language: English
• Published: BMC 2012-03-01
• Series: BMC Infectious Diseases
• Subjects: <it>L. braziliensis</it>; Macrophages; Chemokines; Subclinical infection
• Online Access: http://www.biomedcentral.com/1471-2334/12/75

<p>Abstract</p> <p>Background</p> <p><it>Leishmania </it>preferentially infects macrophages, which allow the parasite to multiply but can also kill the parasite. Although the T cell response in human leishmaniasis is well-characterized, little is known about the concomitant macrophage behavior. The aim of this study was to characterize the macrophage immune response after <it>Leishmania braziliensis </it>infection in cells derived from cutaneous leishmaniasis (CL) or mucosal leishmaniasis (ML) patients, subclinical individuals (SC) and healthy control subjects (HS).</p> <p>Methods</p> <p>Peripheral blood mononuclear cell-derived macrophages from the different groups were exposed to <it>L. braziliensis in vitro </it>and were evaluated for susceptibility to <it>Leishmania </it>infection, ability to kill <it>Leishmania </it>and chemokine/cytokine production. Nitric Oxide (NO) and superoxide (O₂^-) levels in the supernatant of infected macrophage cultures were monitored.</p> <p>Results</p> <p>After exposure to <it>L. braziliensis</it>, peripheral blood mononuclear cell-derived macrophages from SC individuals showed a lower infection rate and a smaller number of intracellular amastigotes compared to cells from CL and ML patients. Macrophages from CL and ML patients produced more chemokines and TNF-α than those from the SC group. Production of NO and O₂^-were detected but did not vary significantly among the different groups.</p> <p>Conclusions</p> <p>Our data indicate that macrophages play a pivotal role in controlling <it>L. braziliensis </it>infection and in leishmaniasis pathology by secreting pro-inflammatory chemokines/cytokines that activate and recruit T cells, overwhelming the inflammatory response.</p>