Division of Drug Delivery Technology, Leiden/Amsterdam Center for Drug Research, Einsteinweg 55, 2333 CC Leiden, The Netherlands.
J Control Release. 2010 Apr 19;143(2):207-14. doi: 10.1016/j.jconrel.2010.01.007. Epub 2010 Jan 13.
Subunit vaccines are generally safer, but often less effective than live attenuated vaccines as they lack the necessary co-stimulatory factors. The formulation of an adjuvant like N-trimethyl chitosan (TMC) with an antigen can overcome its poor immunogenicity. Recent data suggest the importance of incorporating the antigen and the adjuvant into one entity for maximum immunostimulatory effect, e.g. by using (nano)particles. In the present paper we introduce the conjugation of an antigen, ovalbumin (OVA), to TMC as an alternative to nanoparticles for subunit vaccination. OVA was covalently linked to TMC using thiol chemistry (SPDP method). The uptake of the resulting TMC-OVA conjugate by dendritic cells (DC) and its effect on DC maturation was assessed in vitro and its immunogenicity was investigated in mice. We found that with the SPDP method a reducible covalent bond between TMC and OVA could be introduced, without disrupting the protein's antigenicity and structure. Uptake of TMC-OVA conjugate by dendritic cells was similar to the uptake of TMC/OVA nanoparticles, over 5-fold increased compared to a solution of OVA and TMC. Mice immunized with TMC-OVA conjugate produced 1000-fold higher OVA specific IgG titers than mice immunized with either OVA or a physical mixture of TMC and OVA. Moreover, these antibody titers were slightly elevated compared to the titers obtained with TMC/OVA nanoparticles. Conjugation of the antigen to an adjuvant is therefore a viable strategy to increase the immunogenicity of subunit vaccines and may provide an alternative to the use of particles.
亚单位疫苗通常更安全，但通常不如减毒活疫苗有效，因为它们缺乏必要的共刺激因子。用佐剂（如 N-三甲基壳聚糖（TMC））与抗原联合可以克服其免疫原性差的问题。最近的数据表明，将抗原和佐剂结合到一个实体中以获得最大的免疫刺激效果非常重要，例如通过使用（纳米）颗粒。在本文中，我们介绍了将抗原卵清蛋白（OVA）与 TMC 缀合作为亚单位疫苗替代纳米颗粒的方法。使用巯基化学（SPDP 法）将 OVA 共价连接到 TMC 上。评估了所得 TMC-OVA 缀合物被树突状细胞（DC）摄取及其对 DC 成熟的影响，并在小鼠中研究了其免疫原性。我们发现，使用 SPDP 方法可以在不破坏蛋白质抗原性和结构的情况下，在 TMC 和 OVA 之间引入可还原的共价键。TMC-OVA 缀合物被树突状细胞摄取的情况与 TMC/OVA 纳米颗粒的摄取情况相似，与 OVA 和 TMC 溶液相比，摄取量增加了 5 倍以上。用 TMC-OVA 缀合物免疫的小鼠产生的 OVA 特异性 IgG 滴度比用 OVA 或 TMC 和 OVA 的物理混合物免疫的小鼠高 1000 倍。此外，与用 TMC/OVA 纳米颗粒获得的滴度相比，这些抗体滴度略有升高。因此，将抗原缀合到佐剂上是提高亚单位疫苗免疫原性的可行策略，并且可以替代颗粒的使用。
