Characterization of Vibrio cholerae neuraminidase as an immunomodulator for novel formulation of oral allergy immunotherapy

To improve current mucosal allergen immunotherapy Vibrio cholerae neuraminidase (NA) was evaluated as a novel epithelial targeting molecule for functionalization of allergen-loaded, poly(D,L-lactide-co-glycolide) (PLGA) microparticles (MPs) and compared to the previously described epithelial targeting lectins wheat germ agglutinin (WGA) and Aleuria aurantia lectin (AAL). All targeters revealed binding to Caco-2 cells, but only NA had high binding specificity to α-L fucose and monosialoganglioside-1. An increased transepithelial uptake was found for NA-MPs in a M-cell co-culture model. NA and NA-MPs induced high levels of IFN-γ and IL10 in naive mouse splenocytes and CCL20 expression in Caco-2. Repeated oral gavage of NA-MPs resulted in a modulated, allergen-specific immune response. In conclusion, NA has enhanced M-cell specificity compared to the other targeters. NA functionalized MPs induce a Th1 and T-regulatory driven immune response and avoid allergy effector cell activation. Therefore, it is a promising novel, orally applied formula for allergy therapy.

Continuous low plasma concentrations of everolimus provides equivalent efficacy to oral daily dosing in mouse xenograft models of human cancer

PURPOSE

Everolimus is a drug used successfully in a number of different oncology indications, but significant on-target toxicities exist. We explored the possibility of improving the therapeutic index (TI) by studying alternative means of administering the drug based upon low continuous dosing.

METHODS

All studies were performed using naïve nude mice or nude mice bearing s.c. human renal 786-O tumours or human breast MDA-MB-468 tumours. Everolimus was administered via a standard emulsion, either i.v., p.o., i.p., s.c., or via s.c. osmotic mini-pumps (MP) or via poly-lactic-co-glycolic (PLGA)-microparticles (PLGA-µP) prepared from everolimus powder injected s.c. Total-drug levels in blood, plasma or tissues were quantified ex vivo by LC-MS/MS. Efficacy studies were performed over 2-3 weeks and toxicity assessed by changes in body weight, glucose and white blood cell count. Effects on tumour activity biomarkers were quantified using reverse-phase protein array.

RESULTS

Everolimus administration s.c. in an emulsion decreased the absorption rate but increased the C _max and bio-availability of everolimus compared to standard approaches of administration p.o. or i.p. Everolimus administration s.c. via MP or PLGA-µP reduced the C _max and provided continuous low concentrations of everolimus in the plasma, which inhibited tumour pS6/S6 to a similar degree to oral administration. Toxicities such as changes in body weight or white blood cell count were unaffected. Provided the everolimus concentration was above the free unbound IC50 for proliferation of the tumour cell line, efficacy could be achieved equivalent to that provided by standard oral administration. However, an overall improvement in the TI could not be demonstrated.

CONCLUSIONS

Continuous low plasma concentrations of everolimus can provide strong efficacy in preclinical models, which if translatable to the clinic may reduce on-target toxicities and so increase the TI.

An antigen-specific semi-therapeutic treatment with local delivery of tolerogenic factors through a dual-sized microparticle system blocks experimental autoimmune encephalomyelitis

Antigen-specific treatments are highly desirable for autoimmune diseases in contrast to treatments which induce systemic immunosuppression. A novel antigen-specific therapy has been developed which, when administered semi-therapeutically, is highly efficacious in the treatment of the mouse model for multiple sclerosis, experimental autoimmune encephalomyelitis (EAE). The treatment uses dual-sized, polymeric microparticles (dMPs) loaded with specific antigen and tolerizing factors for intra- and extra-cellular delivery, designed to recruit and modulate dendritic cells toward a tolerogenic phenotype without systemic release. This approach demonstrated robust efficacy and provided complete protection against disease. Therapeutic efficacy required encapsulation of the factors in controlled-release microparticles and was antigen-specific. Disease blocking was associated with a reduction of infiltrating CD4⁺ T cells, inflammatory cytokine-producing pathogenic CD4⁺ T cells, and activated macrophages and microglia in the central nervous system. Furthermore, CD4⁺ T cells isolated from dMP-treated mice were anergic in response to disease-specific, antigen-loaded splenocytes. Additionally, the frequency of CD86^hiMHCII^hi dendritic cells in draining lymph nodes of EAE mice treated with Ag-specific dMPs was reduced. Our findings highlight the efficacy of microparticle-based drug delivery platform to mediate antigen-specific tolerance, and suggest that such a multi-factor combinatorial approach can act to block autoimmunity.