Intranasal nanoemulsion vaccine confers long‐lasting immunomodulation and sustained unresponsiveness in a murine model of milk allergy

Abstract

Background: Immunotherapy for food allergy requires prolonged treatment protocols and, in most cases, does not lead to durable modulation of the allergic immune response. We have demonstrated an intranasal (IN) nanoemulsion adjuvant that redirects allergen-specific Th2 responses toward Th1 and Th17 immunity, and protects from allergen challenge after only 2-4 monthly administrations. Here, we investigate the ability of this technology to provide long-term modulation of allergy in a murine model of cow's milk allergy.Methods: Six weeks after sensitization to bovine casein, mice received four, monthly IN immunizations with nanoemulsion formulated with casein. Protection from casein challenge was assessed at 4 and 16 weeks after the final vaccine administration. Results:The NE vaccine significantly blunted the physiological responses to allergen challenge, and this effect persisted for at least 16 weeks. The protection from challenge was associated with the suppression of casein-specific Th2 immunity and induced Th1 and Th17 cytokines as well as induction of IL-10. Of interest, while immunized animals showed significantly decreased Th2 cytokine responses, cow's milkspecific IgE remained elevated in the serum at levels associated with reactivity in control sensitized animals. Protection was associated with suppressed mast cell activation and markedly reduced mast cell infiltration into the small intestine. Conclusion:The sustained unresponsiveness of at least 16 weeks after vaccination suggests that the nanoemulsion vaccine alters the allergic phenotype in a persistent manner different from traditional desensitization, and this leads to long-term suppressive effects on allergic disease without eliminating serum IgE. K E Y W O R D S allergy treatment, food allergy, immunotherapy and tolerance induction, immunotherapy vaccines and mechanisms, vaccines | 873 O'KONEK Et al.

Mucosal Nanoemulsion Allergy Vaccine Suppresses Alarmin Expression and Induces Bystander Suppression of Reactivity to Multiple Food Allergens

“…The bystander protection did require immunization with an allergen to which the animal was previously sensitized, suggesting the non-specific reduction of food allergic reactions required prior sensitization and immune recognition of the vaccine. This bystander suppression of reactivity was maintained for at least 8 weeks, supporting our previous work that demonstrated the long-term sustained unresponsiveness induced by this approach ( 27 ). The mechanism of this effect appeared to be redirection of the underlying immune polarization from a Th2 to a Th1 phenotype, especially since no suppressive activity was demonstrated with treatment using either the adjuvant alone or with an immunogen for which there was no pre-existing allergy (HBsAg).…”

“…NE was formulated with two allergens and maintained therapeutic efficacy for both foods. Based on the protein loading capacity of NE, formulation with more than 2 allergens would also be possible and the therapy only has to be administered three to four times to achieve sustained unresponsiveness of at least 4 months (25)(26)(27). Given that long-term protection can be achieved with only a few doses administered at monthly intervals, this approach would significantly reduce the burden on patients with multiple food allergies over daily, allergen-specific immunotherapies.…”

“…with viral and bacterial antigens, this formulation induces robust systemic and mucosal immunity, and cell-mediated immune responses are polarized towards Th1 and Th17 (16)(17)(18)(19)(20)(21)(22)(23)(24). We have previously reported that therapeutic immunization with NE and antigen/allergen can suppress established Th2-polarized immunity and protect from allergen challenge in murine models of food allergy (25)(26)(27)(28). NE-based allergy vaccines induced sustained unresponsiveness lasting at least 16 weeks, and protection was associated with increased IL-10 and regulatory T cells.…”

Piper nigrum extract attenuates food allergy by decreasing Th2 cell response and regulating the Th17/Treg balance

“…The blood samples were collected 1 hr after the sixth OVA challenge according to the previous studies (Lee et al, 2018;O'Konek et al, 2020) and placed at room temperature for 30 min, and then, centrifuged to obtain serum. Enzyme-linked immunosorbent assay (ELISA) kits (BD Biosciences, San Diego, CA, USA) were used to measure serum levels of total IgE, OVA-specific IgE, and mucosal mast cell protease-1 (mMCP-1) following the manufacturer's instructions.…”

“…In order to determine cytokines, the blood, intestine, and spleen were removed from the mouse model 1 hr after the sixth OVA challenge (Lee et al, 2018;O'Konek et al, 2020), and then, the blood samples were centrifuged to obtain serum. The intestinal tract was first cut up with scissors, and then the tissue was homogenized and dissolved in a 1 ml lysis buffer containing protease inhibitor and phosphatase inhibitor, then centrifuged to obtain supernatant of tissue homogenetes.…”