Department of Molecular Biology & Genetic Engineering, College of Basic Sciences & Humanities, Pantnagar, Uttarakhand, India.
Department of Veterinary Pharmacology & Toxicology, College of Veterinary & Animal Sciences, Pantnagar, Uttarakhand, India.
J Med Microbiol. 2022 Apr;71(4). doi: 10.1099/jmm.0.001529.
The conventional adjuvants used in vaccines have limitations like induction of an imbalanced Th1 and Th2 immune response. To overcome this limitation, novel adjuvants and newer forms of existing adjuvants like calcium phosphate nanoparticles are being tested. Calcium phosphate adjuvanted outer membrane proteins vaccine may work as an efficient, safe and cost effective vaccine against Typhi. Our goals were to evaluate the potential of calcium phosphate nanoparticles as an adjuvant using outer membrane proteins (Omps) of Typhi as antigens for immune response, with montanide (commercially available adjuvant) as control, and its toxicity in rats. Calcium phosphate adjuvanted outer membrane proteins nanoparticles were synthesized and characterized. The efficacy of vaccine formulation in mice and toxicity assay were carried out in rats. The calcium phosphate nanoparticles varying in size between 20-50 nm had entrapment efficiency of 41.5% and loading capacity of 54%. The calcium phosphate nanoparticle-Omps vaccine formulation (nanoparticle-Omps) induced a strong humoral immune response, which was significantly higher than the control group for the entire period of study. In the montanide-Omps group the initial very high immune response declined steeply and then remained steady. The immune response induced by nanoparticle-Omps did not change appreciably. The cell mediated immune response as measured by lymphocyte proliferation assay and delayed type hypersensitivity test showed a higher response (<0.01) for the nanoparticles-Omps group as compared to montanide-Omps group. The bacterial clearance assay also showed higher clearance in the nanoparticles-Omps group as compared to montanide-Omps group (approx 1.4%). The toxicity analysis in rats showed no difference in the values of toxicity biomarkers and blood chemistry parameters, revealing vaccine formulation was non-toxic in rats. Calcium phosphate nanoparticles as adjuvant in vaccines is safe, have good encapsulation and loading capacity and induce a strong cell mediated, humoral and protective immune response.
常规佐剂在疫苗中的应用存在局限性，如诱导不平衡的 Th1 和 Th2 免疫反应。为了克服这一限制，新型佐剂和现有佐剂的新型形式，如磷酸钙纳米粒子，正在被测试。磷酸钙佐剂的外膜蛋白疫苗可能是一种针对伤寒的高效、安全且具有成本效益的疫苗。我们的目标是评估磷酸钙纳米粒子作为佐剂的潜力，使用伤寒的外膜蛋白（Omps）作为抗原，产生免疫反应，并以 montanide（市售佐剂）作为对照，同时评估其在大鼠中的毒性。合成并表征了磷酸钙纳米粒子佐剂的外膜蛋白纳米粒子。在小鼠中进行了疫苗配方的功效评估，并在大鼠中进行了毒性试验。大小在 20-50nm 之间的磷酸钙纳米粒子具有 41.5%的包封效率和 54%的载药能力。磷酸钙纳米粒子-Omps 疫苗制剂（纳米粒子-Omps）诱导了强烈的体液免疫反应，在整个研究期间均明显高于对照组。在 montanide-Omps 组中，初始的高免疫反应急剧下降，然后保持稳定。纳米粒子-Omps 诱导的免疫反应没有明显变化。通过淋巴细胞增殖试验和迟发型超敏反应试验测量的细胞介导免疫反应显示，纳米粒子-Omps 组的反应（<0.01）高于 montanide-Omps 组。细菌清除试验也显示纳米粒子-Omps 组的清除率高于 montanide-Omps 组（约 1.4%）。大鼠的毒性分析显示，毒性生物标志物和血液化学参数的值没有差异，表明疫苗制剂在大鼠中是无毒的。磷酸钙纳米粒子作为疫苗佐剂是安全的，具有良好的包封和载药能力，并能诱导强烈的细胞介导、体液和保护性免疫反应。
