The mechanisms of anti-PEG immune response are different in the spleen and the lymph nodes

Dual-Labelled Nanoparticles Inform on the Stability of Fluorescent Labels In Vivo

“…With the radioactive signal, the nanoparticles have a bioavailability of ~70% (67 ± 11% for BD650 and 79 ± 10% for Cy5). This is comparable to our previous data obtained with similar nanoparticles [ 40 ]. When comparing the AUC obtained with both signals, the radioactive and fluorescence profiles after IP administration are more similar to each other than they were with IV injections.…”

“…These values were chosen because we previously showed that nanoparticles with PEG densities above 20 PEG chains per 100 nm 2 had comparable pharmacokinetics [ 29 ]. Here again, the pharmacokinetics of the particles were similar, and comparable to the circulation profiles obtained previously [ 40 ] irrespective of the fluorescent conjugate encapsulated ( Supplementary Figure S5A ). The blood exposures (as quantified by the area under the plasma vs. time curve (AUC 0–24h )) for the BD650, Cy5 and AZ647 formulations were 647 ± 65, 631 ± 28 and 593 ± 67 %ID·h per gram of blood, respectively ( Supplementary Table S5 ).…”

“…Combinatorial synthesis allows the preparation of nanoparticles using mixtures of polymers [ 29 ]. In the past, we employed the approach to reproducibly synthetize radioactive [ 28 , 29 ] or fluorescent nanoparticles [ 27 , 40 ]. In the present work, we combined PEG-PLA, fluorescent PLA and [ 14 C]-PLGA to prepare nanoparticles that are both fluorescent and radioactive.…”

“…This extravascular administration route requires an absorption phase that increases interactions between nanoparticles and biological components, affording opportunities to understand what happens to degradation products. We have shown previously that nanoparticles injected IP are absorbed into the systemic circulation [ 40 ], but that the peritoneum delays the absorption of larger colloids [ 37 ].…”

Macro-microporous ZIF-8 MOF complexed with lysosomal pH-adjusting hexadecylsulfonylfluoride as tumor vaccine delivery systems for improving anti-tumor cellular immunity

“…It has been reported that with subcutaneous administration of vaccines, one part of vaccines will be taken up by tissue-resident DCs at the injection site to migrate to secondary lymphoid organs to achieve antigen presentation, while the other part will be transported to the blood along with tissue fluid and finally to the spleen to trigger the immune response. [49][50][51] To study antigen localization in the spleen and inguinal lymph node, the C57BL/6 mice were inoculated subcutaneously with 100 μL of Cy5.5-OVA, SOM-ZIF-8/Cy5.5-OVA, or SOM-ZIF-8/ HDSF/Cy5.5-OVA vaccine formulations. Two or seven days after immunization, the spleen and inguinal lymph nodes were isolated for ex vivo imaging and immunohistochemical analysis.…”