Nanoformulated Single-Stranded RNA-Based Adjuvant with a Coordinative Amphiphile as an Effective Stabilizer: Inducing Humoral Immune Response by Activation of Antigen-Presenting Cells.

As agonists of TLR7/8, single-stranded RNAs (ssRNAs) are safe and promising adjuvants that do not cause off-target effects or innate immune overactivation. However, low stability prevents them from mounting sufficient immune responses. This study evaluates the adjuvant effects of ssRNA derived from the cricket paralysis virus intergenic region internal ribosome entry site, formulated as nanoparticles with a coordinative amphiphile, containing a zinc/dipicolylamine complex moiety as a coordinative phosphate binder, as a stabilizer for RNA-based adjuvants. The nanoformulated ssRNA adjuvant was resistant to enzymatic degradation in vitro and in vivo, and that with a coordinative amphiphile bearing an oleyl group (CA-O) was approximately 100 nm, promoted effective recognition, and improved activation of antigen-presenting cells, leading to better induction of neutralizing antibodies following single immunization. Hence, CA-O may increase the efficacy of ssRNA-based adjuvants, proving useful to meet the urgent need for vaccines during pathogen outbreaks.

Endogenous n-3 Polyunsaturated Fatty Acids Are Beneficial to Dampen CD8+ T Cell-Mediated Inflammatory Response upon the Viral Infection in Mice.

Omega-3 (n-3) polyunsaturated fatty acids (PUFAs) have been known to exert anti-inflammatory effects on various disease states. However, its effect on CD8+ T cell-mediated immunopathology upon viral infection has not been well elucidated yet. In this study, we investigated the possible implication of n-3 PUFAs in CD8+ T cell responses against an acute viral infection. Infection of FAT-1 transgenic mice that are capable of synthesizing n-3 PUFAs from n-6 PUFAs with lymphocytic choriomeningitis virus (LCMV) resulted in significant reduction of anti-viral CD8+ T cell responses. Interestingly, expansion of adoptively transferred wild-type (WT) LCMV-specific T cell receptor (TCR) transgenic CD8+ (P14) T cells into FAT-1 mice was significantly decreased. Also, activation of anti-viral CD4+ helper T cells was reduced in FAT-1 mice. Importantly, P14 cells carrying the fat-1 gene that were adoptively transferred into WT mice exhibited a substantially decreased ability to proliferate and produce cytokines against LCMV infection. Together, n-3 PUFAs attenuated anti-viral CD8+ T cell responses against an acute viral infection and thus could be used to alleviate immunopathology mediated by the viral infection.