Antigen stabilizing hydrogels based on cyclodextrins and polyethylene glycol act as type-2 adjuvants with suppressed local irritation.

Recent viral pandemics have increased global demand for vaccines. However, the supply of effective and safe vaccine not only to developed countries but also developing countries with inadequate storage equipment is still challenging due to the lack of robust systems which improve the efficacy and the stability of vaccines with few side effects. In our previous study, polypseudorotaxane (PPRX) hydrogels based on cyclodextrin (CyD) and polyethylene glycol (PEG) significantly improved the stability of antibody preparations and showed no serious adverse effects after subcutaneous injection, suggesting the possibility as safe vaccine formulations to stabilize an antigen protein. Moreover, recent studies have reported that one of the CyD derivatives, hydroxypropyl-ß-CyD (HP-ß-CyD), acts as an adjuvant to enhance protective type-2 immune responses. However, it is still unknown that CyD PPRX hydrogels enhance not only the stability of an antigen protein but also its immunogenicity with tolerable side effects. Here, we demonstrate that α- and γ-CyD PPRX hydrogels containing an antigen protein significantly induce antigen-specific type-2 immune responses. Moreover, α- and γ-CyD PPRX hydrogels showed negligible local irritation at the injection site, although subcutaneous injection of α-CyD alone induced skin lesion. Finally, shaking stability of the antigen protein at room temperature was significantly improved by being included in α- and γ-CyD PPRX hydrogels. These results propose the possibility of α- and γ-CyD PPRX hydrogels as novel vaccine formulations which improve both the immunogenicity and stability of an antigen protein with suppressed local irritation.

Mask wearing increases eye involvement during smiling: a facial EMG study.

The use of face masks has become ubiquitous. Although mask wearing is a convenient way to reduce the spread of disease, it is important to know how the mask affects our communication via facial expression. For example, when we are wearing the mask and meet a friend, are our facial expressions different compared to when we are not? We investigated the effect of face mask wearing on facial expression, including the area around the eyes. We measured surface electromyography from zygomaticus major, orbicularis oculi, and depressor anguli oris muscles, when people smiled and talked with or without a mask. Only the actions of the orbicularis oculi were facilitated by wearing the mask. We thus concluded that mask wearing may increase the recruitment of the eyes during smiling. In other words, we can express joy and happiness even when wearing a face mask.

Fasting impairs type 2 helper T cell infiltration in the lung of an eosinophilic asthma mouse model.

Eosinophilic asthma is a form of bronchial asthma that is caused by the pulmonary infiltration of eosinophils and accounts for approximately half of the patients with severe asthma. Several cell types of the immune system in synergy with the epithelial cells of the lung provoke an inflammatory response in patients with asthma. Recently, the effect of fasting on immune cells and inflammation has attracted considerable attention. Therefore, we examined whether fasting may serve as novel preventive strategy in patients with asthma. In our study, we employed a previously established mouse model of eosinophilic asthma. C57BL/6 mice were inoculated intranasally with interleukin-33 and ovalbumin (OVA) in order to induce eosinophil infiltration in the lung and subjected to a 48-h long fasting period directly after or 7 days postinoculation. We used flow cytometry to characterise infiltrated immune cells in the lung and measured the quantity of inflammatory cytokines as well as antigen-specific immunoglobins (Ig) by ELISA. Our results indicated that fasting lowered the number of eosinophilic pulmonary infiltrates in the eosinophilic asthma model mice. Furthermore, fasting suppressed anti-OVA IgG1 production. Fasting suppressed Th2 cytokine production by impairing Th2 accumulation in the lung. The findings suggest that fasting may be a novel preventive strategy for eosinophilic asthma.

DAMP-Inducing Adjuvant and PAMP Adjuvants Parallelly Enhance Protective Type-2 and Type-1 Immune Responses to Influenza Split Vaccination.

Recently, it was reported that 2-hydroxypropyl-ß-cyclodextrin (HP-ß-CyD), a common pharmaceutical additive, can act as a vaccine adjuvant to enhance protective type-2 immunogenicity to co-administered seasonal influenza split vaccine by inducing host-derived damage-associated molecular patterns (DAMPs). However, like most other DAMP-inducing adjuvants such as aluminum hydroxide (Alum), HP-ß-CyD may not be sufficient for the induction of protective type-1 (cellular) immune responses, thereby leaving room for improvement. Here, we demonstrate that a combination of HP-ß-CyD with a humanized TLR9 agonist, K3 CpG-ODN, a potent pathogen-associated molecular pattern (PAMP), enhanced the protective efficacy of the co-administered influenza split vaccine by inducing antigen-specific type-2 and type-1 immune responses, respectively. Moreover, substantial antigen-specific IgE induction by HP-ß-CyD, which can cause an allergic response to immunized antigen was completely suppressed by the addition of K3 CpG-ODN. Furthermore, HP-ß-CyD- and K3 CpG-ODN-adjuvanted influenza split vaccination protected the mice against lethal challenge with high doses of heterologous influenza virus, which could not be protected against by single adjuvant vaccines. Further experiments using gene deficient mice revealed the unique immunological mechanism of action in vivo, where type-2 and type-1 immune responses enhanced by the combined adjuvants were dependent on TBK1 and TLR9, respectively, indicating their parallel signaling pathways. Finally, the analysis of immune responses in the draining lymph node suggested that HP-ß-CyD promotes the uptake of K3 CpG-ODN by plasmacytoid dendritic cells and B cells, which may contributes to the activation of these cells and enhanced production of IgG2c. Taken together, the results above may offer potential clinical applications for the combination of DAMP-inducing adjuvant and PAMP adjuvant to improve vaccine immunogenicity and efficacy by enhancing both type-2 and type-1 immune responses in a parallel manner.