Neutrophils and Macrophages Cooperate in Host Resistance againstLeishmania braziliensisInfection

Abstract

Neutrophils play an active role in the control of infections caused by intracellular pathogens such as Leishmania. In the present study, we investigated the effect of neutrophil depletion at the time of Leishmania braziliensis infection of BALB/c mice and how neutrophils interact with the infected macrophage to promote parasite elimination. The in vivo depletion of neutrophils led to a significant increase in parasite load and enhanced the Th1-Th2 immune response in this experimental model of infection. BALB/c mice coinoculated with both parasites and live neutrophils displayed lower parasite burdens at the site of infection and in the draining lymph nodes. In vitro, we observed that live neutrophils significantly reduced the parasite load in L. braziliensis-infected murine macrophages, an effect not observed with Leishmania major. L. braziliensis elimination was dependent on the interaction between neutrophils and macrophages and was associated with TNF-α as well as superoxide production. Furthermore, cooperation between neutrophils and macrophages toward parasite elimination was also observed in experiments performed with L. braziliensis-infected human cells and, importantly, with two other New World Leishmania species. These results indicate that neutrophils play an important and previously unappreciated role in L. braziliensis infection, favoring the induction of a protective immune response.

Chronicity of Dermal Leishmaniasis Caused by Leishmania panamensis Is Associated with Parasite-Mediated Induction of Chemokine Gene Expression

“…They act as temporary hosts and facilitators of macrophage colonization during the early stage of infection with L. major, L. donovani, and L. infantum, thereby promoting establishment of infection (12,(27)(28)(29). Conversely, they can cooperate with macrophages in the induction of a protective immune response and parasite elimination (30,31). Although a neutrophilic infiltrate in the mid-dermis has been described for cutaneous lesions caused by L. panamensis with 0.5 to 8 months of disease evolution, 94% of these patients presented lesions Յ4 months before diagnosis (32).…”

Human and Mouse Macrophages Collaborate with Neutrophils To Kill Larval Strongyloides stercoralis

“…Macrophages and neutrophils are professional phagocytes that collaborate in the immune responses to several intracellular pathogens through activation by cytokines or granular components (29,30). Macrophages activate neutrophils following Mycobacterium avium infection through the release of IL-8 (29).…”

Modulation of immune response in experimental Chagas disease

“…During the acute phase of the infection by T. cruzi and other protozoa like Leishmania sp [50] and Plasmodium sp, induction to the inflammatory response is necessary to be able to control parasitaemia [51] . However, if the classi-…”