A NANOSTRUCTURE OF ASCORBYL PALMITATE USED AS VACCINE PLATFORM IMPROVE ANTIGEN SPECIFIC MEMORY RESPONSE AND RETAINS THE ANTIGEN AT THE INJECTION SITE

RUIZ MORENO, FEDERICO N ; MARIN, CONSTANZA ; DHO NICOLAS D ; PASCUAL, MARÍA M ; ALLEMANDI DANIEL A ; PALMA, SANTIAGO D ; PISTORESI PALENCIA, MARÍA C ; MORÓN, VICTOR G ; MALETTO BELKYS A

Congreso; REUNION ANUAL SAIC, SAI, SAFIS 2020; 2020

SAIC, SAI, SAFIS

In the last years our group has been working on a new vaccination strategy using ovalbumin antigen (OVA) and CpG-ODN formulated with a liquid crystal nanostructure (Coa-ASC16) formed by self-assembly of 6-O-ascorbyl palmitate. Here, we shown the different formulations effect on antigen-specific response and depot. C57BL/6 mice were subcutaneously immunized with a single-dose of OVA and CpG-ODN nanoformulated with Coa-ASC16 (OCC), room temperature (RT) OVA and CpG-ODN solution (OC), OVA and CpG-ODN solution heated and then cooled down to RT (OCø), OVA solution heated and then cooled down to RT and CpG-ODN solution at RT (Oø/C), and OVA solution at RT with heated CpG-ODN solution and then cooled down to RT (O/Cø). Heating processes recreated the conditions of the antigen, immunostimulant or both in the nanoformulation. To evaluated the depot effect at the injection site these formulations were prepared using fluorescent-dye labeled OVA and analyzed by Odyssey® CLx. OVA-specific IgG, IgG1 and IgG2a titers were evaluated by ELISA at several time points p.i. The germinal center (CG) and memory B cell response in splenocytes 167 days p.i (6 days post challenge) was determined by flow cytometry. Antibody response: IgG: OCC titers were higher than OCø and Oø/C at 145 days p.i. (p<0.001); post challenge OCC titers were comparable to OCø group. IgG2a: there were no differences between the groups. IgG1: OCC induced higher titers than OCø and Oø/C, pre (p<0.001) and post challenge (p<0.05). O/Cø did not present any response. CG and B cell memory: OCC generated higher OVA-specific IgG memory (p<0.05) and CG response (p<0.05) than the other groups at 167 days p.i. Injection site: OVA signal was higher than other groups since 8hs p.i (p <0.0001) until 168 hs p.i. (p <0.01). Conclusion: OCC induced higher IgG and IgG1 titers than the other groups, also induce a higher number of OVA specific memory B cells and CG response. Coa-ASC16 generates OVA depot at the injection site.