A non-affinity purification process for GMP production of prefusion-closed HIV-1 envelope trimers from clades A and C for clinical evaluation.

Metastable glycosylated immunogens present challenges for GMP manufacturing. The HIV-1 envelope (Env) glycoprotein trimer is covered by N-linked glycan comprising half its mass and requires both trimer assembly and subunit cleavage to fold into a prefusion-closed conformation. This conformation, the vaccine-desired antigenic state, is both metastable to structural rearrangement and labile to subunit dissociation. Prior reported GMP manufacturing for a soluble trimer stabilized in a near-native state by disulfide (SOS) and Ile-to-Pro (IP) mutations has employed affinity methods based on antibody 2G12, which recognizes only ~30% of circulating HIV strains. Here, we develop a scalable manufacturing process based on commercially available, non-affinity resins, and we apply the process to current GMP (cGMP) production of trimers from clades A and C, which have been found to boost cross-clade neutralizing responses in vaccine-test species. The clade A trimer, which we named "BG505 DS-SOSIP.664", contained an engineered disulfide (201C-433C; DS) within gp120, which further stabilized this trimer in a prefusion-closed conformation resistant to CD4-induced triggering. BG505 DS-SOSIP.664 was expressed in a CHO-DG44 stable cell line and purified with initial and final tangential flow filtration steps, three commercially available resin-based chromatography steps, and two orthogonal viral clearance steps. The non-affinity purification enabled efficient scale-up, with a 250 L-scale cGMP run yielding 9.6 g of purified BG505 DS-SOSIP.664. Antigenic analysis indicated retention of a prefusion-closed conformation, including recognition by apex-directed and fusion peptide-directed antibodies. The developed manufacturing process was suitable for 50 L-scale production of a second prefusion-stabilized Env trimer vaccine candidate, ConC-FP8v2 RnS-3mut-2G-SOSIP.664, yielding 7.8 g of this consensus clade C trimer. The successful process development and purification scale-up of HIV-1 Env trimers from different clades by using commercially available materials provide experimental demonstration for cGMP manufacturing of trimeric HIV-Env vaccine immunogens, in an antigenically desired conformation, without the use of costly affinity resins.

The Future Application of Organ-on-a-Chip Technologies as Proving Grounds for MicroBioRobots.

An evolving understanding of disease pathogenesis has compelled the development of new drug delivery approaches. Recently, bioinspired microrobots have gained traction as drug delivery systems. By leveraging the microscale phenomena found in physiological systems, these microrobots can be designed with greater maneuverability, which enables more precise, controlled drug release. Their function could be further improved by testing their efficacy in physiologically relevant model systems as part of their development. In parallel with the emergence of microscale robots, organ-on-a-chip technologies have become important in drug discovery and physiological modeling. These systems reproduce organ-level functions in microfluidic devices, and can also incorporate specific biological, chemical, and physical aspects of a disease. This review highlights recent developments in both microrobotics and organ-on-a-chip technologies and envisions their combined use for developing future drug delivery systems.

Open-source, 3D-printed Peristaltic Pumps for Small Volume Point-of-Care Liquid Handling.

Microfluidic technologies are frequently employed as point-of-care diagnostic tools for improving time-to-diagnosis and improving patient outcomes in clinical settings. These microfluidic devices often are designed to operate with peripheral equipment for liquid handling that increases the cost and complexity of these systems and reduces their potential for widespread adoption in low resource healthcare applications. Here, we present a low-cost (~$120), open-source peristaltic pump constructed with a combination of three dimensional (3D)-printed parts and common hardware, which is amenable to deployment with microfluidic devices for point-of-care diagnostics. This pump accepts commonly available silicone rubber tubing in a range of sizes from 1.5 to 3 mm, and is capable of producing flow rates up to 1.6 mL min-1. This device is programmed with an Arduino microcontroller, allowing for custom flow profiles to fit a wide range of low volume liquid handling applications including precision liquid aliquoting, flow control within microfluidics, and generation of physiologically relevant forces for studying cellular mechanobiology within microfluidic systems.