Adjuvants are essential components of subunit vaccines added to enhance immune responses to antigens through immunomodulation. Very few adjuvants have been approved for human use by regulatory agencies due to safety concerns. Current subunit vaccine adjuvants approved for human use are very effective in promoting humoral immune responses but are less effective at promoting T-cell immunity. In this study, we evaluated a novel pure enantio-specific cationic lipid 1,2-dioleoyl-3-trimethylammonium-propane (R-DOTAP) as an immunomodulator for subunit vaccines capable of inducing both humoral- and cellular-mediated immunity. Using recombinant protein antigens derived from SARS-CoV2 spike or novel computationally optimized broadly reactive influenza antigen (COBRA) proteins, we demonstrated that R-DOTAP nanoparticles promoted strong cellular- and antibody-mediated immune responses in both monovalent and bivalent vaccines. R-DOTAP-based vaccines induced antigen-specific and polyfunctional CD8+ and CD4+ effector T cells and memory T cells, respectively. Antibody responses induced by R-DOTAP showed a balanced Th1/Th2 type immunity, neutralizing activity and protection of mice from challenge with live SARS-CoV2 or influenza viruses. R-DOTAP also facilitated significant dose sparing of the vaccine antigens. These studies demonstrate that R-DOTAP is an excellent immune stimulator for the production of next-generation subunit vaccines containing multiple recombinant proteins.
|State||Published - Feb 2023|
Bibliographical noteFunding Information:
This study was funded, in part, by the National Institute of Allergy and Infectious Diseases, a component of the NIH, Department of Health and Human Services, under contract 75N93019C00052 to T.M.R. and sub-contract to J.G.W., the National Center for Research Resources and the National Center for Advancing Translational Sciences, the National Institutes of Health, through Grant UL1TR001998 through Center for Clinical and Translational Science Pilot Funding to J.G.W. and S.K.G. and The PDS Biotechnology sponsored research grants to J.G.W. In addition, the flow cytometry work was partially funded by the University of Kentucky Flow Cytometry & Immune Monitoring core facility supported in part by the Office of the Vice President for Research, the Markey Cancer Center and an NCI Center Core Support Grant (P30 CA177558) to the University of Kentucky Markey Cancer Center. T.M.R. is also supported as an Eminent Scholar through the Georgia Research Alliance.
J.G.W. has received research funding from PDS Biotechnology. J.G.W., S.K.G. and M.W. have received stock options from PDS Biotechnology. S.K.G., F.B.A., K.S., L.W., J.D. and G.C. are officers in PDS Biotechnology. The remaining authors declare no conflict of interest.
© 2023 by the authors.
- immune stimulatory cationic lipids
- vaccine adjuvants
- vaccine induced T cell immunity
ASJC Scopus subject areas
- Infectious Diseases