Leishmania 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 Leishmania infection are poorly understood. Previous studies synthesized ␣-1,2-trimannose cap sugars on latex beads and demonstrated that C57BL/6 mice coinoculated with Leishmania major and trimannose-coated beads produced significantly higher levels of interleukin-12p40 (IL-12p40) and other proinflammatory, type 1 cytokines than mice inoculated with L. major alone within the first 48 h of infection. However, as L. major 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 L. major alone, coinoculated with carrier beads and L. major, or coinoculated with trimannose-coated beads and L. major. Trimannose treatment of L. majorinfected 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 Ϫ/Ϫ ) mice lack the ability to detect trimannose. When MR Ϫ/Ϫ mice were infected with L. major and treated with trimannose beads, they did not have decreased lesion size. Leishmania-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.KEYWORDS Leishmania, carbohydrate, cutaneous leishmaniasis, mannose receptor G lycoconjugate cell surface molecules of many pathogens are often key virulence factors that promote pathogen survival (1-5). Antigen glycosylation has become increasingly recognized as a critical component of immune modulation by pathogens (6-9). However, the glycan portion of the glycoconjugate was mainly considered a modulatory component with little to no antigenic properties independent of the lipid or protein that it was conjugated to. Tzianabos et al. (10) and Cobb et al. (11) were the first to describe CD4 ϩ T cell proliferation mediated by zwitterionic polysaccharides of Bacteroides fragilis, which indicated that some carbohydrates can function as antigens without attachment to a lipid or protein. This property of carbohydrates has led to interest in the mechanisms of how pathogen-derived carbohydrates modulate host immune responses, resistance to treatment (12), and their potential role in novel

A formal total synthesis of pancratistatin was accomplished by conversion of advanced intermediates, used in the synthesis of narciclasine, to pancratistatin precursors via Myers’ reductive transposition as the key strategic step. The synthesis began with the whole cell fermentation of m-dibromobenzene with JM109(pDTG601a), a recombinant strain that over-expresses toluene dioxygenase, which provided the corresponding cis-dihydrodiol 16 as a single isomer with complete optical purity. The key reductive transposition of the allylic alcohol 8a to olefin 9a allowed for further installation of the C-1/C-2 trans-diol, ­required for the pancratistatin scaffold, through the introduction of a cyclic sulfate and its subsequent opening. The formal synthesis of pancratistatin was accomplished in 14 steps (12 operations) from commercially available m-dibromobenzene. Experimental and spectral data are provided for all new compounds.

Leishmaniasis, a neglected tropical disease, currently infects approximately 12 million people worldwide with 1 to 2 million new cases each year in predominately underdeveloped countries. The treatment of the disease is severely underdeveloped due to the ability of the Leishmania pathogen to evade and abate immune responses. In an effort to develop anti-leishmaniasis vaccines and adjuvants, novel carbohydrate-based probes were made to study the mechanisms of immune modulation. In this study, a new bioerodible polyanhydride microparticle was designed and conjugated with a glycodendrimer molecular probe. This molecular probe incorporates a pathogen-like multivalent display of α-1,2-trimannose, for which a more efficient synthesis was designed, with a tethered fluorophore. Further attachment of the glycodendrimer to a biocompatible, surface eroding microparticle allows for targeted uptake and internalization of the pathogen-associated oligosaccharide by phagocytic immune cells. The α-1,2-trimannose-linked bioerodible microparticles were found to be safe after administration into the footpad of mice and demonstrated a similar response to α-1,2-trimannose-coated latex beads during L. major footpad infection. Furthermore, the bioerodible microparticles allowed for investigation of the role of pathogen-associated oligosaccharides for recognition by pathogen-recognition receptors during L. major-induced leishmaniasis.