Local retention of antibodies in vivo with an injectable film embedded with a fluorogen-activating protein

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• 作者：Wen Liu^a ; Matthew J. Saunders^c ; ^d ; ¹ ; Christina Bagia^a ; Eric C. Freeman^e ; Yong Fan^f ; ^d ; Ellen S. Gawalt^b ; ^g ; Alan S. Waggoner^c ; ^d ; Wilson S. Meng^a ; ^{meng@duq.edu" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Bioaffinity film ; Fluorescent imaging ; Antibody formulation ; Single-chain variable fragment ; Mathematical simulation ; Self-assembling peptide ; Fluorogen-activating protein ; EAK16 ; Dimerized light chain-5 (dL5) ; Controlled release ; Draining lymph nodes
• 刊名：Journal of Controlled Release
• 出版年：2016
• 出版时间：28 May 2016
• 年：2016
• 卷：230
• 期：Complete
• 页码：1-12
• 全文大小：1421 K

文摘

Herein we report an injectable film by which antibodies can be localized in vivo. The system builds upon a bifunctional polypeptide consisting of a fluorogen-activating protein (FAP) and a β-fibrillizing peptide (βFP). The FAP domain generates fluorescence that reflects IgG binding sites conferred by Protein A/G (pAG) conjugated with the fluorogen malachite green (MG). A film is generated by mixing these proteins with molar excess of EAK16-II, a βFP that forms β-sheet fibrils at high salt concentrations. The IgG-binding, fluorogenic film can be injected in vivo through conventional needled syringes. Confocal microscopic images and dose–response titration experiments showed that loading of IgG into the film was mediated by pAG^MG bound to the FAP. Release of IgG in vitro was significantly delayed by the bioaffinity mechanism; 26% of the IgG were released from films embedded with pAG^MG after five days, compared to close to 90% in films without pAG^MG. Computational simulations indicated that the release rate of IgG is governed by positive cooperativity due to pAG^MG. When injected into the subcutaneous space of mouse footpads, film-embedded IgG were retained locally, with distribution through the lymphatics impeded. The ability to track IgG binding sites and distribution simultaneously will aid the optimization of local antibody delivery systems.