Vaccine against peanut allergy based on engineered virus-like particles displaying single major peanut allergens

BACKGROUND

Peanut allergy is a severe and increasingly frequent disease with high medical, psychosocial, and economic burden for affected patients and wider society. A causal, safe, and effective therapy is not yet available.

OBJECTIVE

We sought to develop an immunogenic, protective, and nonreactogenic vaccine candidate against peanut allergy based on virus-like particles (VLPs) coupled to single peanut allergens.

METHODS

To generate vaccine candidates, extracts of roasted peanut (Ara R) or the single allergens Ara h 1 or Ara h 2 were coupled to immunologically optimized Cucumber Mosaic Virus-derived VLPs (CuMVtt). BALB/c mice were sensitized intraperitoneally with peanut extract absorbed to alum. Immunotherapy consisted of a single subcutaneous injection of CuMVtt coupled to Ara R, Ara h 1, or Ara h 2.

RESULTS

The vaccines CuMVtt-Ara R, CuMVtt-Ara h 1, and CuMVtt-Ara h 2 protected peanut-sensitized mice against anaphylaxis after intravenous challenge with the whole peanut extract. Vaccines did not cause allergic reactions in sensitized mice. CuMVtt-Ara h 1 was able to induce specific IgG antibodies, diminished local reactions after skin prick tests, and reduced the infiltration of the gastrointestinal tract by eosinophils and mast cells after oral challenge with peanut. The ability of CuMVtt-Ara h 1 to protect against challenge with the whole extract was mediated by IgG, as shown via passive IgG transfer. FcγRIIb was required for protection, indicating that immune complexes with single allergens were able to block the allergic response against the whole extract, consisting of a complex allergen mixture.

CONCLUSIONS

Our data suggest that vaccination using single peanut allergens displayed on CuMVtt may represent a novel therapy against peanut allergy with a favorable safety profile.

A Single Monoclonal Antibody against the Peanut Allergen Ara h 2 Protects against Systemic and Local Peanut Allergy

BACKGROUND

Peanut allergy is the most prevalent and dangerous food allergy. Peanuts consist of a large number of different allergens and peanut-allergic patients are frequently sensitized to multiple allergens. Hence, conventional desensitization approaches aim at targeting as many allergens as possible.

METHODS

The monoclonal anti-Ara h 2 antibody (mAb) was produced by hybridoma cells derived from WT BALB/c mice after immunization with a vaccine based on virus-like particles coupled to Ara h 2. BALB/c mice were sensitized intraperitoneally with peanut extract absorbed to alum and mAbs were applied i.v. Challenge was performed the next day with the whole peanut extract intravenously and via skin prick test.

RESULTS

Here we show in peanut-allergic mice that a single high-affinity mAb specific for Ara h 2 is able to block systemic and local allergic reactions induced by the complex peanut extract. We confirm in vitro binding of the mAb to the inhibitory low-affinity FcγRIIb receptor using a sensitive biosensor and demonstrate in vivo that protection was dependent on FcγRIIb.

CONCLUSION

A single mAb specific for Ara h 2 is able to improve local and systemic allergic symptoms induced by the whole allergen mixture.

Vaccination with nanoparticles combined with micro-adjuvants protects against cancer

BACKGROUND

Induction of strong T cell responses, in particular cytotoxic T cells, is a key for the generation of efficacious therapeutic cancer vaccines which yet, remains a major challenge for the vaccine developing world. Here we demonstrate that it is possible to harness the physiological properties of the lymphatic system to optimize the induction of a protective T cell response. Indeed, the lymphatic system sharply distinguishes between nanoscale and microscale particles. The former reaches the fenestrated lymphatic system via diffusion, while the latter either need to be transported by dendritic cells or form a local depot.

METHODS

Our previously developed cucumber-mosaic virus-derived nanoparticles termed (CuMV_TT-VLPs) incorporating a universal Tetanus toxoid epitope TT830-843 were assessed for their draining kinetics using stereomicroscopic imaging. A nano-vaccine has been generated by coupling p33 epitope as a model antigen to CuMV_TT-VLPs using bio-orthogonal Cu-free click chemistry. The CuMV_TT-p33 nano-sized vaccine has been next formulated with the micron-sized microcrystalline tyrosine (MCT) adjuvant and the formed depot effect was studied using confocal microscopy and trafficking experiments. The immunogenicity of the nanoparticles combined with the micron-sized adjuvant was next assessed in an aggressive transplanted murine melanoma model. The obtained results were compared to other commonly used adjuvants such as B type CpGs and Alum.

RESULTS

Our results showed that CuMV_TT-VLPs can efficiently and rapidly drain into the lymphatic system due to their nano-size of ~ 30 nm. However, formulating the nanoparticles with the micron-sized MCT adjuvant of ~ 5 μM resulted in a local depot for the nanoparticles and a longer exposure time for the immune system. The preclinical nano-vaccine CuMV_TT-p33 formulated with the micron-sized MCT adjuvant has enhanced the specific T cell response in the stringent B16F10p33 murine melanoma model. Furthermore, the micron-sized MCT adjuvant was as potent as B type CpGs and clearly superior to the commonly used Alum adjuvant when total CD8⁺, specific p33 T cell response or tumour protection were assessed.

CONCLUSION

The combination of nano- and micro-particles may optimally harness the physiological properties of the lymphatic system. Since the nanoparticles are well defined virus-like particles and the micron-sized adjuvant MCT has been used for decades in allergen-specific desensitization, this approach may readily be translated to the clinic.