Garinot M, Piras-Douce F, Probeck P, Chambon V, Varghese K, Liu Y, Luna E, Drake D, Haensler J. A potent novel vaccine adjuvant based on straight polyacrylate.
INTERNATIONAL JOURNAL OF PHARMACEUTICS-X 2020;
2:100054. [PMID:
32776001 PMCID:
PMC7398942 DOI:
10.1016/j.ijpx.2020.100054]
[Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 07/06/2020] [Accepted: 07/18/2020] [Indexed: 02/03/2023]
Abstract
A structure-activity study was conducted to identify the structural characteristics underlying the adjuvant activity of straight (i.e. non-crosslinked) polyacrylate polymers (PAAs) in order to select a new PAA adjuvant candidate for future clinical development. The study revealed that the adjuvant effect of PAA was mainly influenced by polymer size (Mw) and dose. Maximal effects were obtained with large PAAs above 350 kDa and doses above 100 μg in mice. Small PAAs below 10 kDa had virtually no adjuvant effect. HPSEC analysis revealed that PAA polydispersity index and ramification had less impact on adjuvanticity. Heat stability studies indicated that residual persulfate could be detrimental to PAA stability. Hence, this impurity was systematically eliminated by diafiltration along with small Mw PAAs and residual acrylic acid that could potentially affect product safety, potency and stability. The selected PAA, termed SPA09, displayed an adjuvant effect that was superior to that of a standard emulsion adjuvant when tested with CMV-gB in mice, even in the absence of binding to the antigen. The induced immune response was dominated by strong IFNγ, IgG2c and virus neutralizing titers. The activity of SPA09 was then confirmed on human cells via the innate immune module of the human MIMIC® system.
Straight polyacrylate (350 kDa < Mw < 650 kDa; termed SPA09) is a strong adjuvant easy to formulate with vaccine antigens
SPA09 induces Th-1 type immune responses in mice, dominated by strong IFN-γ, IgG2c and virus neutralizing titers
SPA09 can activate human antigen presenting cells when tested via the innate immune module (PTE) of the human MIMIC® system
SPA09 constitutes a straightforward new adjuvant candidate for future clinical development
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