Nanoparticle Vaccines Adopting Virus-like Features for Enhanced Immune Potentiation

Chattopadhyay, Saborni; Chen, Jui-Yi; Chen, Hui-Wen; Hu, Che-Ming Jack

Using fluorescence microlymphangiography, the investigators showed a clear distinction between 25 nm and 100 nm particles regarding their lymphatic uptake. Following injection into mouse tails, 25 nm particles were efficiently drained to the lymphatic vessels, whereas the interstitial transport of 100 nm particles was less efficient. In contrast to prior studies with liposomes, the 25 nm particles also showed higher lymph node accumulation, resulting in a 10-fold enhancement in lymph node delivery as compared to the 100 nm particles (Fig. 3B, C) [13] . Such enhanced lymph node delivery, which was absent in earlier liposomal studies, could be attributed to both increased colloidal stability of the polymeric nanoparticles and the particles' ability to elicit complement activation. As the polypropylene sulfide particles were functionalized with surface hydroxyl groups to trigger the proteolytic cleavage of C3 complement protein, the danger signal associated with the complement activation could facilitate macrophage uptake upon lymph node entry [153] , thereby reducing particle escape from the lymph node's filtering mechanism.