2.5 Adjuvants
ISPA adjuvant is composed of alpha-tocopherol (TOCOP), phospatidylcholine (DPPC), stearylamine (STEA), cholesterol (CHOL) and QuilA saponin. The ISPA particles have a cage-like structure of 73.0 ± 1.5 nm in size as assessed by dynamic light scattering. First, liposomes were prepared with final proportions of TOCOP: 0.00074% (0.017 mM), DPPC: 0.320% (4.35 mM), STEA: 0.0216% (0.8 mM) and CHOL: 0.143% (3.70 mM). Then, the suspension was extruded through a 50 nm pore membrane and a QuilA saponin solution in acetate buffer was added to liposomes (6.5 mg/300µl per ml of liposomes) and extruded through a 50 nm membrane pore (Bertona et al., 2017; Prochetto et al., 2017).
The commercial oil adjuvant (CA) used was ISA206 (Seppic, Paris, France). The formulations were prepared following the manufacturer’s indications in a proportion adjuvant: antigen 60:40.