Micro-/Nanotechnology - Therapeutics

Syringe-Free: Oral Vaccine against Helicobacter pylori

To fight antibiotic-resistant pathogens, and to ensure wide-spread application and high compliance, oral vaccinations are desirable, but pose drug delivery complications. An efficient nanoparticle system for vaccination against stomach ulcer causing Helicobacter pylori was recently reported.

Vaccination is a brilliant way to control or even totally eradicate diseases, and it is also the last resort in dealing with antibiotics resistance—the tendency of pathogens to defy treatment due to increased resistance.

Vaccines are usually administered intravenously by syringe—a method ensuring that the drug can act fast on the whole system while eliminating the need to overcome the external barriers of the body, and avoids the race with renal elimination of the vaccine.

However, injections are not only uncomfortable for the patient, thereby minimizing compliance, they require trained medical staff, a clean environment, and large material consumption. Due to those reasons, the development of oral vaccines to stop advancing diseases is highly desired.

In contrast to their intravenous counterparts, orally administered drugs, however, must mitigate the low pH of the stomach, have to penetrate the mucus, and need to cross the transepithelial absorption barrier. In consequence, it is quite challenging to develop an oral drug with high efficacy.

One pathogen that is not met by an efficient oral vaccine, yet, is the bacterium Helicobacter pylori (H. pylori), which is the cause of stomach ulcers, and also of chronic gastritis and gastric cancer. In their research, Quanming Zou, Xun Sun, and their co-workers from Sichuan University and the Third Military Medical University P.R. China report a novel nanoparticle-based drug-delivery system capable of efficient oral vaccination against H. pylori.

To achieve both cargo protection and mucosal penetration, the researchers designed an anionic, hydrophilic, mercaptosuccinic acid-functionalized poly(ethylene glycol) derivative, termed PEG-Suc. Transephithelial penetration was achieved by the cell-penetrating peptide poly-L-arginine. Together with the active antigen, both components were subjected to a mild electrostatic self-assembly process to obtain nanoparticles.

Interaction analysis revealed that the protective, muco-penetrative PEG-component slowly dissociates in the mucus, allowing action of the cell-penetrating peptide. This two-sided strategy increased cellular uptake in vitro more than 4-fold compared to unfunctionalized cargo.  In vivo experiments showed that antibody levels in mice were indeed increased by the vaccine, conferring efficient immunity against H. pylori.

 

To learn more about this promising oral vaccine that could eradicate infection-related stomach ulcers, and to read other exciting research articles, please visit the Advanced Functional Materials homepage.

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