Biological characterization of a novel class of toll-like receptor 7 agonists designed to have reduced systemic activity.

BACKGROUND AND PURPOSE Toll-like receptor 7 (TLR7) agonists have potential in the treatment of allergic diseases. However, the therapeutic utility of current low molecular weight TLR7 agonists is limited by their systemic activity, resulting in unwanted side effects. We have developed a series of TLR7-selective 'antedrugs', including SM-324405 and AZ12441970, which contain an ester group rapidly cleaved in plasma to reduce systemic exposure. EXPERIMENTAL APPROACH Agonist activity at TLR7 of the parent ester and acid metabolite was assessed in vitro in reporter cells and primary cells from a number of species. Pharmacokinetics following a dose to the lungs was assessed in mice and efficacy evaluated in vivo with a mouse allergic airway model. KEY RESULTS Compounds were selective agonists for TLR7 with no crossover to TLR8 and were metabolically unstable in plasma with the acid metabolite showing substantially reduced activity in a number of assays. The compounds inhibited IL-5 production and induced IFN-α, which mediated the inhibition of IL-5. When dosed into the lung the compounds were rapidly metabolized and short-term exposure of the 'antedrug' was sufficient to activate the IFN pathway. AZ12441970 showed efficacy in a mouse allergic airway model with minimal induction of systemic IFN-α, consistent with the low plasma levels of compound. CONCLUSIONS AND IMPLICATIONS The biological and metabolic profiles of these TLR7-selective agonist 'antedrug' compounds are consistent with a new class of compound that could be administered locally for the treatment of allergic diseases, while reducing the risk of systemic side effects. LINKED ARTICLE This article is commented on by Kaufman and Jacoby, pp. 569-572 of this issue. To view this commentary visit http://dx.doi.org/10.1111/j.1476-5381.2011.01758.x.

The effect of cyclosporin A, FK506, and rapamycin on the murine chronic graft-versus-host response--an in vivo model of Th2-like activity.

We have evaluated the effects of three potent immunosuppressive agents: cyclosporin A, FK506, and rapamycin, on a murine chronic graft-versus-host response (chronic GVHR). The chronic GVHR has previously been described to be a Th2-like response, and is characterized by a marked splenomegaly and hyper-IgE production in the early stages of the response. The effects of the immunosuppressive agents on both splenomegaly and hyper-IgE were measured 3 weeks after the induction of the chronic GVHR. Rapamycin was found to inhibit both splenomegaly and the hyper-IgE response in a dose-dependent manner. Unexpectedly cyclosporin A and FK506 were found to potentiate markedly both the splenomegaly and hyper-IgE response at low doses before exhibiting an inhibitory effect at higher doses. We propose the differences of activity seen with rapamycin compared with cyclosporin A and FK506 may be explained by their different mechanisms of action, and also by the selectivity of low dose cyclosporin A and FK506 for Th1-like lymphocytes. The implications of these observations are discussed in relation to the use of these immunosuppressives for the treatment of Th2-like diseases.

[The syndrome of renal and pulmonary vasculitis with positive neutrophil anticytoplasmic antibodies and antibasement membrane antibodies. A case report]. / Síndrome de vasculitis renal y pulmonar con anticuerpos anticitoplasma de neutrófilos y anticuerpos antimembrana basal positivos. Informe de un caso.

The authors present a case of Goodpasture's syndrome with necrotizing vasculitis of spleen and appendix. Serological examination shows antiglomerular basement membrane antibodies and antineutrophil cytoplasmic antibodies. The authors review the literature to establish if this or other similar cases can be considered a distinct disease entity. The authors also mention the laboratory methods that are currently being used to classify more precisely the vasculitides associated with glomerulonephritis.

Síndrome de vasculitis renal y pulmonar con anticuerpos anticitoplasma de neutrófilos y anticuerpos antimembrana basal positivos: informe de un caso / The syndrome of renal and pulmonary vasculitis with positive neutrophil anticytoplasmic antibodies and antibasement membrane antibodies: a case report

The authors present a case of Goodpasture's syndrome with necrotizing vasculitis of spleen and appendix. Serological examination shows antiglomerular basement membrane antibodies and antineutrophil cytoplasmic antibodies. The authors review the literature to establish if this or other similar cases can be considered a distinct disease entity. The authors also mention the laboratory methods that are currently being used to classify more precisely the vasculitides associated with glomerulonephritis