Minthostachys verticillata essential oil microcapsule as possible candidate for vaccine adjuvant

ARSAUTE S.; PAREDES A; REINOSO EB; MONTIRONI I.; CAMACHO N; PALMA S; CAMPRA NA; RAVIOLO J; MALETTO B; CARIDDI LN

San Miguel de Tucumán

Congreso; Reunion SAI 2019; 2019

In a previous study we demonstrated that Minthostachys verticillata essential oil (2.5 mg/ml) has adjuvant effect using OVA as antigen. The aim of this study was to determine the effect of microencapsulated EO (MCEO) against humoral and cellular immune response using Enterococcus faecium as antigen. Balb/c mice (n=4 per group) were immunized by subcutaneous injection (day 0) and revaccinated (day 14 and 28) as follows: Group 1:100 μl saline solution; Group 2:100 μl E. faecium bacterin 6x109 CFU/ml; Group 3: 100 μl bacterin + Incomplete Freund's Adjuvant 50%; Group 4: 100 μl bacterin +EO (2,5 mg/ml); Group 5: 100 μl bacterin + microcapsule wall material (2,5 mg/ml); Group 6: 100 μl bacterin + MCEO (5 mg/ml). Seven days after last revaccination, serum samples were collected and analyzed for antigen-specific total antibodies (IgG, IgM and IgA) by indirect ELISA. In addition, splenic lymphocytes were obtained for XTT proliferation assay and quantification of CD4+ and CD8+ T cells by flow cytometer. Any mouse died; however only in group 3 a significant induration at the injection site was observed. MCEO induced the highest antibodies levels (p