Luna, E., et al. SPA14 liposomes combining saponin with fully synthetic TLR4 agonist provide adjuvanticity to hCMV vaccine candidate.
NPJ Vaccine, 2024 Dec 19, 9(1):253. PMID: 39702373.
An innovative novel adjuvant system, SPA14, which combines the QS-21 saponin with a synthetic TLR4 agonist, E6020, in cholesterol-containing liposomes, has shown promising results in enhancing the immune response. It outperforms existing adjuvant systems. By combining QS-21 with E6020 in the SPA14 leveraged the strengths of both components to achieve a more robust immune response against the targeted antigens, such as CMV gB and PC in mice and NHP.
SPA14 effectively stimulated the secretion of various cytokines and chemokines; increased the number of IgG2c- and IgG1-secreting B cells in the spleens showing significant activation of B cells in immunized mice; exhibited an adjuvant effect comparable to that of AS01B in enhancing B and T cell responses to the CMV gB and PC vaccine; induced significant virus-neutralizing antibody titers in NHP observed over an extended period; demonstrated a more pronounced Th-1 biased immune response compared to AS01B, as evidenced by the increased frequency of IFN-γ and IL-5 secreting T cells specific to glycoprotein B (gB) and phosphoprotein (PC) in mice; induced similar levels of IFN-γ and IL-4 responses in T cells, comparable to AS01B, indicating effective T cell activation in NHP.
SPA14 was well-tolerated by the immunized macaques, with no severe clinical symptoms reported.
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