The adsorption of allergoids and 3-O-desacyl-4′-monophosphoryl lipid A (MPL®) to microcrystalline tyrosine (MCT) in formulations for use in allergy immunotherapy

Abstract

Infectious disease vaccine potency is affected by antigen adjuvant adsorption. WHO and EMA guidelines recommend limits and experimental monitoring of adsorption in vaccines and allergy immunotherapies. Adsorbed allergoids and MPL® in MATA-MPL allergy immunotherapy formulations effectively treat IgE mitigated allergy. Understanding vaccine antigen adjuvant adsorption allows optimisation of potency and should be seen as good practice; however current understanding is seldom applied to allergy immunotherapies. The allergoid and MPL® adsorption to MCT in MATA-MPL allergy immunotherapy formulations was experimental determination using specific allergen IgE allerginicity and MPL® content methods. Binding forces between MPL® and MCT were investigated by competition binding experiments. MATA-MPL samples with different allergoids gave results within 100-104% of the theoretical 50μg/mL MPL® content. Unmodified drug substance samples showed significant desirable IgE antigenicity, 1040-170 QAU/mL. MATA-MPL supernatant samples with different allergoids gave results of ≤2 μg/mL MPL® and ≤0.1-1.4 QAU/mL IgE antigenicity, demonstrating approximately ≥96 & 99% adsorption respectively. Allergoid and MPL® adsorption in different MATA-MPL allergy immunotherapy formulations is consistent and meets guideline recommendations. MCT formulations treated to disrupt electrostatic, hydrophobic and ligand exchange interactions, gave an MPL® content of ≤2 μg/mL in supernatant samples. MCT formulations treated to disrupt aromatic interactions, gave an MPL® content of 73-92 μg/mL in supernatant samples. MPL® adsorption to l-tyrosine in MCT formulations is based on interactions between the 2-deoxy-2-aminoglucose backbone on MPL® and aromatic ring of l-tyrosine in MCT, such as C-H⋯π interaction. MCT could be an alternative adjuvant depot for some infectious disease antigens.

Virus-Like Particle (VLP) Plus Microcrystalline Tyrosine (MCT) Adjuvants Enhance Vaccine Efficacy Improving T and B Cell Immunogenicity and Protection against Plasmodium berghei/vivax

“…MCT has been formulated with numerous proteins [30,31], but to date has not been formulated with VLPs. In order to visualize VLP-absorbance to MCT, we labelled CMVtt VLPs with Alexa Fluor 488 (Alexa Fluor ® 488 Protein Labeling Kit, Thermo Fisher Scientific), formulated with MCT and analysed the MCT crystals by confocal microscopy.…”

“…Of particular note is the conferred immunological synergy of using MCT and VLP. It is hypothesised that MCT offers a distinct mode of adsorption [30] and immunological profile that presents synergy with Th1 adjuvants [61] that warrants further exploration in this and other vaccine targets where the mix-/match- combination of new adjuvants are sought. Further work requires testing of alternative malaria antigens in conjunction with PvTRAP plus MCT and VLP to achieve a protection against the parasite.…”

Allergen immunotherapy in people, dogs, cats and horses – differences, similarities and research needs

“…The most urgent need is to improve safety and achieve shorter treatment periods to improve patient compliance (Table ) . This can be accomplished by Th1 adjuvants such as monophosphoryl lipid A, instead of aluminium hydroxide. SCIT using allergoids was shown to be safer than injections with native allergens .…”

Comparison of a novel microcrystalline tyrosine adjuvant with aluminium hydroxide for enhancing vaccination against seasonal influenza

“…Whereas other manufacturers still use mainly aluminium hydroxide (alum), AT uses Micro-Crystalline Tyrosine (MCT), a natural amino acid formulation, in its vaccine formulations. MCT exhibits a high adsorptive power for proteins at neutral pH, it enhances the induction of IgG antibodies with no unusual propensity to stimulate IgE, has a half-life of 48 h at the site of injection while delivering a sustained release of antigens for prolonged immune exposure and, unlike alum, it is fully metabolised within the body [19, 21, 22]. Its mechanistic pathways as an adjuvant are currently sought and an ongoing study has recently highlighted induction of specific T cell responses.…”

“…As such, has been combined successfully with Monophosphoryl Lipid A (MPL) which offers a novel ultra-short-course allergy immunotherapy as a named patient product [23], of which, has recently completed a successful phase II dose ranging trial in Europe [24], while different iterations (allergy indications) of the platform are in current clinical development both in the EU and US. MPL is a TLR-4 agonist able to modulate Th1 immune reactivity, its physicochemical and biological compatibility with MCT has been described previously [19–22]. …”