Vangala Anil, Kirby Daniel, Rosenkrands Ida, Agger Else Marie, Andersen Peter, Perrie Yvonne
Medicines Research Unit, School of Life and Health Sciences, Aston University, Birmingham, B4 7ET, UK.
J Pharm Pharmacol. 2006 Jun;58(6):787-99. doi: 10.1211/jpp.58.6.0009.
Vesicular adjuvant systems composing dimethyldioctadecylammonium (DDA) can promote both cell-mediated and humoral immune responses to the tuberculosis vaccine fusion protein in mice. However, these DDA preparations were found to be physically unstable, forming aggregates under ambient storage conditions. Therefore there is a need to improve the stability of such systems without undermining their potent adjuvanticity. To this end, the effect of incorporating non-ionic surfactants, such as 1-monopalmitoyl glycerol (MP), in addition to cholesterol (Chol) and trehalose 6,6'-dibehenate (TDB), on the stability and efficacy of these vaccine delivery systems was investigated. Differential scanning calorimetry revealed a reduction in the phase transition temperature (T(c)) of DDA-based vesicles by approximately 12 degrees C when MP and cholesterol (1:1 molar ratio) were incorporated into the DDA system. Transmission electron microscopy (TEM) revealed the addition of MP to DDA vesicles resulted in the formation of multi-lamellar vesicles. Environmental scanning electron microscopy (ESEM) of MP-Chol-DDA-TDB (16:16:4:0.5 micromol) indicated that incorporation of antigen led to increased stability of the vesicles, perhaps as a result of the antigen embedding within the vesicle bilayers. At 4 degrees C DDA liposomes showed significant vesicle aggregation after 28 days, although addition of MP-Chol or TDB was shown to inhibit this instability. Alternatively, at 25 degrees C only the MP-based systems retained their original size. The presence of MP within the vesicle formulation was also shown to promote a sustained release of antigen in-vitro. The adjuvant activity of various systems was tested in mice against three subunit antigens, including mycobacterial fusion protein Ag85B-ESAT-6, and two malarial antigens (Merozoite surface protein 1, MSP1, and the glutamate rich protein, GLURP). The MP- and DDA-based systems induced antibody responses at comparable levels whereas the DDA-based systems induced more powerful cell-mediated immune responses.
由二甲基二十八烷基铵（DDA）组成的囊泡佐剂系统可促进小鼠对结核疫苗融合蛋白的细胞介导免疫反应和体液免疫反应。然而，这些DDA制剂在物理上不稳定，在常温储存条件下会形成聚集体。因此，需要在不削弱其强大佐剂活性的情况下提高此类系统的稳定性。为此，研究了除胆固醇（Chol）和6,6'-二山嵛酸海藻糖（TDB）外，加入非离子表面活性剂（如1-单棕榈酰甘油（MP））对这些疫苗递送系统稳定性和功效的影响。差示扫描量热法显示，当MP和胆固醇（摩尔比1:1）加入DDA系统时，基于DDA的囊泡的相变温度（T(c)）降低了约12℃。透射电子显微镜（TEM）显示，向DDA囊泡中添加MP会导致形成多层囊泡。MP-Chol-DDA-TDB（16:16:4:0.5微摩尔）的环境扫描电子显微镜（ESEM）表明，抗原的掺入导致囊泡稳定性增加，这可能是由于抗原嵌入囊泡双层膜中。在4℃下，DDA脂质体在28天后显示出明显的囊泡聚集，尽管添加MP-Chol或TDB可抑制这种不稳定性。另外，在25℃下，只有基于MP的系统保持其原始大小。囊泡制剂中MP的存在还显示可促进抗原在体外的持续释放。在小鼠中测试了各种系统对三种亚单位抗原的佐剂活性，包括分枝杆菌融合蛋白Ag85B-ESAT-6和两种疟疾抗原（裂殖子表面蛋白1，MSP1，以及富含谷氨酸的蛋白，GLURP）。基于MP和DDA的系统诱导的抗体反应水平相当，而基于DDA的系统诱导更强大的细胞介导免疫反应。
