Immune response induced by New World Leishmania species in C57BL/6 mice

Abstract

In the present study, C57BL/6 mice were inoculated with metacyclic Leishmania amazonensis or L. braziliensis promastigotes. While these animals were capable of controlling the infection by L. braziliensis, they developed chronic lesions with elevated numbers of parasites when infected by L. amazonensis. The differences in parasite control were associated with a decreased production of IFN-gamma and TNF by lymph node cells from L. amazonensis-infected mice. Furthermore, these animals presented decreased spleen cell proliferation and activation of germinal centers. In addition, we compared the ability of these parasites to hydrolyze extracellular ATP and AMP. While the ATPase activity of both parasite species was similar, L. amazonensis promastigotes presented higher AMP hydrolytic activity. This increased activity may lead to an increased production of adenosine, which has been shown to present anti-inflammatory activity and may thus be involved in the establishment of the immunosuppression observed in mice infected by L. amazonensis.

Neutrophils and Macrophages Cooperate in Host Resistance againstLeishmania braziliensisInfection

“…It was also shown that the CD28/ CD80-CD86 interaction on neutrophil/macrophages induces IFN-␥ production, restricting the growth of L. major (44). Importantly, the mechanisms leading to cure and resistance to Leishmania infection are associated with macrophage activation, resulting from TNF-␣-and IFN-␥-induced production of free radicals and ultimately with destruction of the intracellular parasites (45,46).…”

Leishmania amazonensis impairs DC function by inhibiting CD40 expression via A2B adenosine receptor activation

“…Leishmania infections can result in a wide spectrum of clinical manifestations and disease outcome is determined both by the parasite species and by Correspondence: Dr. Luís C. C. Afonso e-mail: afonso@nupeb.ufop.br the host immune response. Leishmania amazonensis differs from other species because it is able to cause chronic non-healing lesions in mouse strains genuinely resistant to other Leishmania species, such as Leishmania braziliensis and Leishmania major [1][2][3]. In humans, L. amazonensis causes diffuse cutaneous leishmaniasis, a condition characterised by a lack of antigen-specific T-cell responses against the parasite [4].…”

The Leishmania-Macrophage Interactions: Role of E-NTPDases and Purinergic Signaling

“…The GP63, a zinc-metalloprotease named glycoprotein 63 (GP63), is another critical virulence factor that has been fully explored [34][35][36][37][38] . However, the E-NTPDases (ecto-nucleoside triphosphate diphosphohydrolases), while less-extensively studied, have been demonstrated and believed to be important infectivity and virulence factors [39][40][41][42][43][44][45][46][47][48] .…”