免疫是一个简单的概念,但对于一些病原体如HIV-1仍然是一个挑战。因此,需要采取新的方法来提高疫苗的效力,以扭转潮流。越来越多的证据表明,与传统的推注注射相比,抗原暴露几天到几周会诱导更强,更持久的免疫反应。这通常会导致抗原在几天内从体内清除。因此,我们开发了一种聚(乙二醇)(PEG)水凝胶平台,以研究持续释放抗原以模拟自然感染动力学的主要可行性。将不同MW(10、20和40kDa)的八臂和四臂PEG大单体端基官能化,以允许通过共价交联形成水凝胶。应用三聚体(Envtri)或单体(Envmono)形式的HIV-1包膜(Env)抗原。将可溶性Env抗原与附着于二氧化硅纳米颗粒的Env制剂(Env-SiNP)进行比较。已知后者与其可溶性对应物相比具有更高的免疫原性。水凝胶在流变行为方面是可调的,允许不同的降解时间和Env-SiNP的释放时间范围超过2天至50天。特异性识别Env的CD4结合位点的VCR01抗体的亲和力测量,显示Envmono-SiNP(Kd=2.1±0.9nM)和Envtri-SiNP(Kd=1.5±1.3nM)的完整性和功能性,分别,从水凝胶释放后受损(释放前Kd:2.1±0.1和7.8±5.3nM,分别)。最后,可溶性Env和Env-SiNPs是两种物理化学不同的化合物,共递送并显示从一个水凝胶中依次释放,这在异源免疫或单剂量疫苗接种方面可能是有益的。总之,这项研究提出了一个可调的,多才多艺适用,和有效的交付平台,可以提高疫苗接种的有效性,也为其他传染病而不是HIV-1。
Immunization is a straightforward concept but remains for some pathogens like HIV-1 a challenge. Thus, new approaches towards increasing the efficacy of vaccines are required to turn the tide. There is increasing evidence that antigen exposure over several days to weeks induces a much stronger and more sustained immune response compared to traditional bolus injection, which usually leads to antigen elimination from the body within a couple of days. Therefore, we developed a poly(ethylene) glycol (PEG) hydrogel platform to investigate the principal feasibility of a sustained release of antigens to mimic natural infection kinetics. Eight-and four-armed PEG macromonomers of different MWs (10, 20, and 40 kDa) were end-group functionalized to allow for hydrogel formation via covalent cross-linking. An HIV-1 envelope (Env) antigen in its trimeric (Envtri) or monomeric (Envmono) form was applied. The soluble Env antigen was compared to a formulation of Env attached to silica nanoparticles (Env-SiNPs). The latter are known to have a higher immunogenicity compared to their soluble counterparts. Hydrogels were tunable regarding the rheological behavior allowing for different degradation times and release timeframes of Env-SiNPs over two to up to 50 days. Affinity measurements of the VCR01 antibody which specifically recognizes the CD4 binding site of Env, revealed that neither the integrity nor the functionality of Envmono-SiNPs (Kd = 2.1 ± 0.9 nM) and Envtri-SiNPs (Kd = 1.5 ± 1.3 nM), respectively, were impaired after release from the hydrogel (Kd before release: 2.1 ± 0.1 and 7.8 ± 5.3 nM, respectively). Finally, soluble Env and Env-SiNPs which are two physico-chemically distinct compounds, were co-delivered and shown to be sequentially released from one hydrogel which could be beneficial in terms of heterologous immunization or single dose vaccination. In summary, this study presents a tunable, versatile applicable, and effective delivery platform that could improve vaccination effectiveness also for other infectious diseases than HIV-1.