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Article

Conjugation of Native-Like HIV-1 Envelope Trimers onto Liposomes Using EDC/Sulfo-NHS Chemistry: Requirements and Limitations

1
Polymun Scientific Immunbiologische Forschung GmbH, 3400 Klosterneuburg, Austria
2
Department of Biotechnology, University of Natural Resources and Life Sciences, 1190 Vienna, Austria
3
University of Vienna, 1010 Vienna, Austria
4
FH Campus Wien, University of Applied Sciences, 1100 Vienna, Austria
5
Institute of Clinical and Molecular Virology, Universitätsklinikum Erlangen, 91054 Erlangen, Germany
*
Author to whom correspondence should be addressed.
Pharmaceutics 2020, 12(10), 979; https://doi.org/10.3390/pharmaceutics12100979
Received: 7 September 2020 / Revised: 13 October 2020 / Accepted: 13 October 2020 / Published: 16 October 2020
The display of native-like human immunodeficiency virus type 1 envelope (HIV-1 Env) trimers on liposomes has gained wide attention over the last few years. Currently, available methods have enabled the preparation of Env-liposome conjugates of unprecedented quality. However, these protocols require the Env trimer to be tagged and/or to carry a specific functional group. For this reason, we have investigated N-(3-Dimethylaminopropyl)-N′-ethylcarbodiimide/N-Hydroxysulfosuccinimide (EDC/Sulfo-NHS) chemistry for its potential to covalently conjugate tag-free, non-functionalized native-like Env trimers onto the surface of carboxyl-functionalized liposomes. The preservation of the liposome’s physical integrity and the immunogen’s conformation required a fine-tuned two-step approach based on the controlled use of β-mercaptoethanol. The display of Env trimers was strictly limited to activated liposomes of positive charge, i.e., liposomes with a positive zeta potential that carry amine-reactive Sulfo-NHS esters on their surface. In agreement with that, conjugation was found to be highly ionic strength- and pH-dependent. Overall, we have identified electrostatic pre-concentration (i.e., close proximity between negatively charged Env trimers and positively charged liposomes established through electrostatic attraction) to be crucial for conjugation reactions to proceed. The present study highlights the requirements and limitations of potentially scalable EDC/Sulfo-NHS-based approaches and represents a solid basis for further research into the controlled conjugation of tag-free, non-functionalized native-like Env trimers on the surface of liposomes, and other nanoparticles. View Full-Text
Keywords: covalent conjugation; EDC/Sulfo-NHS; HIV-1; intrastructural help; liposomes; native-like Env trimers; particulate display; pre-concentration; protein-liposome conjugates; tag-free conjugation; vaccines covalent conjugation; EDC/Sulfo-NHS; HIV-1; intrastructural help; liposomes; native-like Env trimers; particulate display; pre-concentration; protein-liposome conjugates; tag-free conjugation; vaccines
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MDPI and ACS Style

Suleiman, E.; Mayer, J.; Lehner, E.; Kohlhauser, B.; Katholnig, A.; Batzoni, M.; Damm, D.; Temchura, V.; Wagner, A.; Überla, K.; Vorauer-Uhl, K. Conjugation of Native-Like HIV-1 Envelope Trimers onto Liposomes Using EDC/Sulfo-NHS Chemistry: Requirements and Limitations. Pharmaceutics 2020, 12, 979. https://doi.org/10.3390/pharmaceutics12100979

AMA Style

Suleiman E, Mayer J, Lehner E, Kohlhauser B, Katholnig A, Batzoni M, Damm D, Temchura V, Wagner A, Überla K, Vorauer-Uhl K. Conjugation of Native-Like HIV-1 Envelope Trimers onto Liposomes Using EDC/Sulfo-NHS Chemistry: Requirements and Limitations. Pharmaceutics. 2020; 12(10):979. https://doi.org/10.3390/pharmaceutics12100979

Chicago/Turabian Style

Suleiman, Ehsan, Julia Mayer, Elisabeth Lehner, Bianca Kohlhauser, Alexandra Katholnig, Mirjam Batzoni, Dominik Damm, Vladimir Temchura, Andreas Wagner, Klaus Überla, and Karola Vorauer-Uhl. 2020. "Conjugation of Native-Like HIV-1 Envelope Trimers onto Liposomes Using EDC/Sulfo-NHS Chemistry: Requirements and Limitations" Pharmaceutics 12, no. 10: 979. https://doi.org/10.3390/pharmaceutics12100979

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