Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen Ø, Denmark.
Pharm Res. 2013 Jan;30(1):140-55. doi: 10.1007/s11095-012-0856-8. Epub 2012 Sep 6.
Understanding the nature of adjuvant-antigen interactions is important for the future design of efficient and safe subunit vaccines, but remains an analytical challenge. We studied the interactions between three model protein antigens and the clinically tested cationic liposomal adjuvant composed of dimethyldioctadecylammonium (DDA) and trehalose 6,6'-dibehenate (TDB).
The effect of surface adsorption to DDA/TDB liposomes on colloidal stability and protein physical stability/secondary structure was investigated by dynamic light scattering, circular dichroism, Fourier transform infrared spectroscopy and differential scanning calorimetry.
Bovine serum albumin and ovalbumin showed strong liposome adsorption, whereas lysozyme did not adsorb. Upon adsorption, bovine serum albumin and ovalbumin reduced the phase transition temperature and narrowed the gel-to-liquid phase transition of the liposomes implying interactions with the lipid bilayer. The protein-to-lipid ratio influenced the liposome colloidal stability to a great extent, resulting in liposome aggregation at intermediate ratios. However, no structural alterations of the model proteins were detected.
The antigen-to-lipid ratio is highly decisive for the aggregation behavior of DDA/TDB liposomes and should be taken into account, since it may have an impact on general vaccine stability and influence the choice of analytical approach for studying this system, also/especially at clinically relevant protein-to-lipid ratios.
了解佐剂-抗原相互作用的性质对于未来设计高效和安全的亚单位疫苗非常重要，但这仍然是一个分析上的挑战。我们研究了三种模型蛋白抗原与临床测试的阳离子脂质体佐剂（由二甲基二辛基铵（DDA）和海藻糖 6,6'-二硬脂酸酯（TDB）组成）之间的相互作用。
通过动态光散射、圆二色性、傅里叶变换红外光谱和差示扫描量热法研究了表面吸附到 DDA/TDB 脂质体上对胶体稳定性和蛋白质物理稳定性/二级结构的影响。
牛血清白蛋白和卵清蛋白表现出强烈的脂质体吸附，而溶菌酶则不吸附。吸附后，牛血清白蛋白和卵清蛋白降低了脂质体的相变温度并缩小了脂质体的凝胶-液相转变范围，这意味着与脂质双层相互作用。蛋白质与脂质的比例对脂质体胶体稳定性有很大影响，导致中间比例下脂质体聚集。然而，未检测到模型蛋白的结构改变。
抗原与脂质的比例对 DDA/TDB 脂质体的聚集行为具有高度决定性，应予以考虑，因为它可能会影响一般疫苗稳定性，并影响研究该系统的分析方法的选择，尤其是在临床相关的蛋白质与脂质比例下。
