Zoster Vaccine Recombinant, Adjuvanted

Small Molecule Calcium Channel Activator Potentiates Adjuvant Activity

There remains an unmet need for reliable fully synthetic adjuvants that increase lasting protective immune responses from vaccines. We previously reported a high-throughput screening for small molecules that extended nuclear factor kappa-light-chain enhancer of activated B cells (NF-κB) activation after a Toll-like receptor 4 (TLR4) ligand, lipopolysaccharide (LPS), stimulation using a human myeloid reporter cell line. We identified compounds with a conserved aminothiazole scaffold including 2D216 [N-(4-(2,5-dimethylphenyl)thiazol-2-yl)-4-(piperidin-1-ylsulfonyl)benzamide], which increased murine antigen-specific antibody responses when used as a co-adjuvant with LPS. Here, we examined the mechanism of action in human cells. Although 2D216 activated the major mitogen-activated protein kinases, it did not interact with common kinases and phosphatases and did not stimulate many of the pattern recognition receptors (PRRs). Instead, the mechanism of action was linked to intracellular Ca2+ elevation via Ca2+ channel(s) at the plasma membrane and nuclear translocation of the nuclear factor of activated T-cells (NFAT) as supported by RNA-seq data, analysis by reporter cells, Ca2+ flux assays, and immunoblots. Interestingly, 2D216 had minimal, if any, activity on Jurkat T cells but induced cytokine production and surface expression of costimulatory molecules on cells with antigen-presenting functions. A small series of analogs of 2D216 were tested for the ability to enhance a TLR4 ligand-stimulated autologous mixed lymphocyte reaction (MLR). In the MLR, 2E151, N-(4-(2,5-dimethylphenyl)thiazol-2-yl)-4-((4-propylpiperidin-1-yl)sulfonyl)benzamide, was more potent than 2D216. These results indicate that a small molecule that is not a direct PRR agonist can act as a co-adjuvant to an approved adjuvant to enhance human immune responses via a complementary mechanism of action.

Multifunctional Dendronized Polypeptides for Controlled Adjuvanticity

Vaccination has been playing an important role in treating both infectious and cancerous diseases. Nevertheless, many diseases still lack proper vaccines due to the difficulty to generate sufficient amounts of antigen-specific antibodies or T cells. Adjuvants provide an important route to improve and direct immune responses. However, there are few adjuvants approved clinically and many of them lack the clear structure/adjuvanticity relationship. Here, we synthesized and evaluated a series of dendronized polypeptides (denpols) functionalized with varying tryptophan/histidine (W/H) molar ratios of 0/100, 25/75, 50/50, 75/25, and 100/0 as tunable synthetic adjuvants. The denpols showed structure-dependent inflammasome activation in THP1 monocytic cells and structure-related activation and antigen cross-presentation in vitro in bone marrow-derived dendritic cells. We used the denpols with bacterial pathogen Coxiella burnetii antigens in vivo, which showed both high and tunable adjuvating activities, as demonstrated by the antigen-specific antibody and T cell responses. The denpols are easy to make and scalable, biodegradable, and have highly adjustable chemical structures. Taken together, denpols show great potential as a new and versatile adjuvant platform that allows us to adjust adjuvanticity based on structure-activity correlation with the aim to fine-tune the immune response, thus advancing vaccine development.