Leishmania-Derived Trimannose Modulates the Inflammatory Response To Significantly Reduce Leishmania major-Induced Lesions.

lipophosphoglycan (LPG) is a key virulence factor, initiating inflammation resulting in cutaneous lesions. LPG is capped by various oligosaccharides. How these glycans are recognized and how they alter the course of infection are poorly understood. Previous studies synthesized α-1,2-trimannose cap sugars on latex beads and demonstrated that C57BL/6 mice coinoculated with and trimannose-coated beads produced significantly higher levels of interleukin-12p40 (IL-12p40) and other proinflammatory, type 1 cytokines than mice inoculated with alone within the first 48 h of infection. However, as infection typically progress over weeks to months, the role of trimannose in altering disease progression over the course of infection was unknown. Wild-type mice were inoculated with either trimannose-coated or carrier (uncoated) beads, infected with alone, coinoculated with carrier beads and , or coinoculated with trimannose-coated beads and Trimannose treatment of -infected mice decreased the parasite load and significantly decreased the lesion size at 14 days postinfection (p.i.) compared to results for nontreated, infected mice. Infected, trimannose-treated mice had decreased IL-12p40 and IL-10 secretion and increased interferon gamma secretion at 14 days p.i. Mannose receptor knockout (MR) mice lack the ability to detect trimannose. When MR mice were infected with and treated with trimannose beads, they did not have decreased lesion size. -derived trimannose represents a novel immunomodulator that provides early type 1-skewed cytokine production to control the parasite load and alter the course of cutaneous leishmaniasis.