Department of Drug Delivery, Helmholtz-Institute for Pharmaceutical Research Saarland-HIPS, Helmholtz-Center for Infection Research-HZI, Saarbruecken, Germany.
Microb Biotechnol. 2012 Mar;5(2):156-67. doi: 10.1111/j.1751-7915.2011.00284.x. Epub 2011 Aug 19.
The living epidermis and dermis are rich in antigen presenting cells (APCs). Their activation can elicit a strong humoral and cellular immune response as well as mucosal immunity. Therefore, the skin is a very attractive site for vaccination, and an intradermal application of antigen may be much more effective than a subcutaneous or intramuscular injection. However, the stratum corneum (SC) is a most effective barrier against the invasion of topically applied vaccines. Products which have reached the stage of clinical testing, avoid this problem by injecting the nano-vaccine intradermally or by employing a barrier disrupting method and applying the vaccine to a relatively large skin area. Needle-free vaccination is desirable from a number of aspects: ease of application, improved patient acceptance and less risk of infection among them. Nanocarriers can be designed in a way that they can overcome the SC. Also incorporation into nanocarriers protects instable antigen from degradation, improves uptake and processing by APCs, and facilitates endosomal escape and nuclear delivery of DNA vaccines. In addition, sustained release systems may build a depot in the tissue gradually releasing antigen which may avoid booster doses. Therefore, nanoformulations of vaccines for transcutaneous immunization are currently a very dynamic field of research. Among the huge variety of nanocarrier systems that are investigated hopes lie on ultra-flexible liposomes, superfine rigid nanoparticles and nanocarriers, which are taken up by hair follicles. The potential and pitfalls associated with these three classes of carriers will be discussed.
活表皮和真皮富含抗原呈递细胞 (APCs)。它们的激活可以引发强烈的体液和细胞免疫反应以及黏膜免疫。因此,皮肤是接种疫苗的非常有吸引力的部位,抗原的皮内应用可能比皮下或肌肉内注射更有效。然而,角质层 (SC) 是阻止经皮应用疫苗入侵的最有效屏障。已经进入临床测试阶段的产品通过皮内注射纳米疫苗或采用破坏屏障的方法并将疫苗应用于相对较大的皮肤区域来避免这个问题。无针接种在许多方面都是理想的:易于应用、提高患者接受度和降低感染风险等。纳米载体可以设计成能够克服 SC 的方式。此外,将抗原纳入纳米载体可以保护不稳定的抗原免受降解,提高 APC 的摄取和处理,并促进 DNA 疫苗的内体逃逸和核传递。此外,缓释系统可以在组织中逐渐建立一个储存库,逐渐释放抗原,从而避免加强剂量。因此,用于经皮免疫的疫苗的纳米制剂是目前一个非常活跃的研究领域。在正在研究的大量纳米载体系统中,希望寄托在超灵活的脂质体、超细刚性纳米粒子和被毛囊吸收的纳米载体上。将讨论这三类载体的潜力和陷阱。