Shaping neonatal immunization by tuning delivery of synergistic adjuvants via nanocarriers

Abstract

Adjuvanted nanocarrier-based vaccines hold substantial potential for applications in novel early-life immunization strategies. Here, via mouse and human age-specific in vitro modelling, we identified the combination of a small molecule STING agonist (2′3′-cyclic GMP-AMP, cGAMP) and a TLR7/8 agonist (CL075) to drive synergistic activation of neonatal dendritic cells and precision CD4 Th cell expansion via the IL-12/IFNγ axis. We further demonstrate that vaccination of neonatal mice with quadrivalent influenza recombinant hemagglutinin (rHA) and an admixture of two polymersome (PS) nanocarriers separately encapsulating- cGAMP (cGAMP-PS) and CL075 (CL075-PS) drove robust T helper (Th)1 bias, high frequency of T follicular helper (TFH) cells and germinal center B (GC B) cells along with IgG2c-skewed humoral response in vivo. Dual loaded cGAMP/CL075-PSs did not outperform admixed cGAMP-PSs and CL075-PSs in vivo. These data validate an optimally designed adjuvantation system, via age-selected small molecule synergy and a multi-component nanocarrier formulation, as an effective approach to induce type 1 immune responses in early life.

Immune-profiling of T helper 1 (Th1), Th2 and Th17 signatures in murine splenocytes by targeting intracellular cytokines

“…This 17-parameter spectral flow cytometry panel was developed to assess the functional cytokines production by conventional T cells which shapes the host immune responses upon natural infection or vaccinations (1). We previously demonstrated antigen specific responses or memory recall responses using microbial proteins (2,3) or peptides (4,5) and immunophenotyped functional cytokines in murine splenic T cell compartment after vaccination. Here, we expanded the flow cytometry panel using spectral flow technology by adding B cells, NK cells, and γδT cell markers, explored the memory T cell compartment and re-validated the panel upon mitogen stimulation using adult C57BL/6 and BALB/c mice strains (Figure 1, Table 2, Online Table 5 and Online Figure 8).…”