Clinical and Vaccine Immunology 2012-10-01

Effects on immunogenicity by formulations of emulsion-based adjuvants for malaria vaccines.

Christopher B Fox, Susan L Baldwin, Thomas S Vedvick, Evelina Angov, Steven G Reed

Index: Clin. Vaccine Immunol. 19(10) , 1633-40, (2012)

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Abstract

New malaria vaccines are urgently needed to improve vaccine protective efficacy. PfCelTOS is a recombinant malaria vaccine antigen that has shown protective efficacy in a small-animal challenge model when combined with a water-in-oil emulsion adjuvant (Montanide ISA 720). In this report, we show that PfCelTOS vaccines containing GLA-SE (a stable oil-in-water emulsion combined with a Toll-like receptor 4 [TLR4] agonist) elicit strong Th1-type immune responses in BALB/c mice. These responses include higher antigen-specific IgG2a antibody titers and more gamma interferon (IFN-γ) production than those seen with a PfCelTOS vaccine containing Montanide ISA 720. Furthermore, reducing the emulsion dose from 2% to 1% or 0.5% (vol/vol) squalene in GLA-SE did not compromise immunogenicity. Emulsion dose titration in the absence of formulated GLA caused some reduction in humoral and cellular immune responses compared to those with the 2% squalene emulsion dose.