Caliway Biopharmaceuticals has recently announced the completion of its initial public offering (IPO) and up-listing from the Emerging Stock Market to the Taipei Exchange (TWSE-6919). The round raised approximately $206 million (NT$6.4 billion), marking it the largest IPO in Taiwan’s biotech industry history and valuing the company at nearly $3 billion. The company is poised for a transformation in 2025, advancing its groundbreaking clinical programmes and strengthening its global market presence. Following its recent record-breaking IPO, BioSpectrum Asia took an opportunity to speak with Vivian Ling, Chief Executive Officer & Chief R&D Officer, Caliway Biopharmaceuticals to explore their innovative contributions in biopharmaceuticals.

Which products are currently under development?

2025 will be a defining year for Caliway as we push ahead with key clinical advancements and corporate milestones, bringing CBL-514 closer to market. CBL-514, a first-in-class small-molecule drug designed to selectively induce adipocyte apoptosis, provides a non-invasive alternative to liposuction for non-surgical fat reduction in medical aesthetics. We are preparing to secure IND approvals for two pivotal Phase 3 studies from the US FDA and Health Canada, a critical step in advancing CBL-514 as the world’s first investigational drug for large-area localised fat reduction. Beyond fat reduction, we’re also submitting a Phase 2 IND application for a new indication focused on improving body weight rebound, expanding CBL-514’s potential applications.

In Q1, Caliway announced positive Phase 2b study results for CBL-514 (0205 Study), the second and final Phase 2b before moving into Phase 3. In Q2, we are preparing for regulatory discussions with the FDA (EOP2) and EMA to align on the next steps for CBL-514’s late-stage development.

A key focus in Q4 will be completing patient enrollment for the Phase 2b study of CBL-514 in Dercum’s Disease (CBL-514 0202DD). CBL-0202DD is being developed as a potential first-in-class therapy for Dercum’s Disease, a rare and painful condition, and has already been granted Fast Track Designation by the FDA and Orphan Drug Designation by both the FDA and EMA. In the early-stage pipeline, CBA-539 offers a novel approach to hyperpigmentation and skin ageing by inhibiting melanin production and transmission, reducing dark spots and evening skin tone, while also stimulating collagen production to improve skin elasticity and firmness for natural, long-lasting results. Expanding into therapeutic applications, CBL-0201OB targets post-weight loss fat accumulation in combination with GLP-1, with a Phase 2 IND submission planned for Q4 2025.

On the corporate front, we are moving forward with a stock split to enhance market liquidity and investor engagement. Additionally, Caliway is now part of the MSCI World Small Cap Index, originally a Q4 goal further strengthening our global investor presence.

In October 2024, we completed our IPO, raising $206 million, making it the largest IPO in Taiwan’s biotech industry history and positioning us among the top biotech IPOs in the US in 2024. This strong financial foundation provides the necessary resources to advance CBL-514 into global pivotal Phase 3 studies, explore additional indications, and further expand our pipeline.

How do you plan to utilise the funds raised from your recent IPO to advance R&D? 

We are strategically deploying IPO funds to accelerate clinical development, expand global partnerships, and strengthen commercialisation efforts. Our key areas of investment include CBL-514 Phase 3 Studies. A significant portion of the funds is being directed toward launching pivotal global multi-centre Phase 3 studies for CBL-514, ensuring a smooth regulatory pathway in key markets. Focusing on new indications development, we are expanding CBL-514’s applications beyond fat reduction by advancing studies for Dercum’s Disease and weight rebound prevention, broadening its potential.

To leverage international licensing and investment experts, we are actively engaging with global investment and licensing professionals to expedite partnership negotiations, increase visibility among potential collaborators, and secure the most favourable commercialisation deals.

For clinical collaboration with KOLs and investigators, we are strengthening relationships with renowned clinical researchers to expand study participation, enhance scientific credibility, and increase visibility in international markets.

We are also expanding global business development and market positioning; and engaging global pharmaceutical companies for licensing and partnerships. We are actively negotiating potential global licensing agreements discussions and strategic partnerships to drive CBL-514’s commercial success.

We are further strengthening our presence at key global industry events to connect with strategic partners and investors by participating in global industry conferences.

Most recently, we participated in IMCAS 2025 in Paris, where we presented the advancements in clinical progress. These efforts maximise our growth potential, drive regulatory approvals, and ensure long-term commercial success.

Could  you tell us about strategic partnerships or licensing agreements with other pharmaceutical companies, key to accelerating the development and commercialisation of your products?

Strategic partnerships are a key driver of Caliway’s growth. We are actively engaging with leading pharmaceutical companies for licensing and co-development opportunities to accelerate CBL-514’s commercialisation. We are also deepening industry connections through key industry events, including BIO, IMCAS, AMWC, JP Morgan Healthcare Conference, and the World Orphan Drug Congress, ensuring we stay at the forefront of global biotech and aesthetic medicine collaborations. These partnerships will be crucial in accelerating product commercialisation and maximising CBL-514’s global impact.

What are your strategies for expanding the market reach of CBL-514, especially in regions like Taiwan, China, Korea, and Southeast Asia?

We are executing a multi-faceted market entry strategy to ensure a structured and phased approach to regulatory approvals and market commercialisation. CBL-514 is a 505(b)(1) first-in-class small-molecule drug designed to address an unmet need in non-surgical fat reduction. Given its innovative mechanism of action and strong clinical data, our primary entry strategy is to focus first on regulatory approvals in the US, our key reference market. Once established, we will gradually expand into additional key regions, including Asia. We are actively engaging with global pharmaceutical companies for potential licensing and other strategic partnerships to accelerate commercialisation. Our pivotal global Phase 3 studies will further strengthen CBL-514’s market valuation and licensing potential, paving the way for successful entry into international markets.

Focusing on the Taiwan biotech market in particular, what are the existing challenges and opportunities?

Biotech development comes with its challenges. Regulatory processes can be complex, which may impact drug development timelines. Another key challenge is the shortage of specialised R&D talent, particularly in pharmaceutical sciences and clinical research. That said, Taiwan has significant advantages that make it an attractive hub for biotech innovation. Taiwan’s healthcare system is highly advanced, cost-effective, and well-structured. The high density of hospitals, cutting-edge medical technology, and experienced medical professionals make it an ideal environment for research, especially in niche indications and rare diseases. Taiwan’s market agility and adaptability also set it apart. The biotech sector here moves fast, making it easier to pivot and innovate. Additionally, many global pharma companies use Taiwan as a strategic entry point, launching products before expanding into larger markets. With its strong medical ecosystem, advanced infrastructure, and strategic position in the region, Taiwan offers a unique and competitive environment for biotech growth and drug development.

Thermo Fisher Scientific agreed to acquire Solventum’s purification and filtration (PF) business for approximately $4.1 billion in cash. The PF business provides purification and filtration technologies used in the production of biologics as well as in medical technologies and industrial applications. The Solventum business operates globally with sites across the Americas, Europe, the Middle East, Africa, and the Asia-Pacific region, and has approximately 2,500 colleagues. In 2024, Solventum’s PF business generated approximately $1 billion in revenue.

Solventum’s PF business is highly complementary to Thermo Fisher’s bioproduction business, according to Marc N. Casper, chairman, president, and CEO of Thermo Fisher. Thermo Fisher has a portfolio of offerings in cell culture media and single-use technologies and Solventum’s filtration portfolio broadens Thermo Fisher’s capabilities in the development and manufacturing of biologics, spanning upstream and downstream workflows, said Casper.

“The addition of Solventum’s business is an outstanding strategic fit with our company and will create significant value for our customers and shareholders,” added Casper. “Solventum’s portfolio of solutions will be valued by our customers, and further demonstrate our disciplined capital deployment strategy which has an excellent track record of creating shareholder value.

“As the trusted partner to our customers, Solventum’s PF business will expand and add differentiated capabilities to our bioprocessing portfolio to better serve our customers in this rapidly growing market.”

The transaction is expected to be completed by the end of 2025 and is subject to customary closing conditions and regulatory approvals. Once the transaction closes, Solventum’s PF business will become part of Thermo Fisher’s Life Sciences Solutions segment.

As new targeted biologic modalities ramp up for commercialization, manufacturing methods must keep pace. If new efficacious therapeutics cannot be produced at reasonable costs they remain in restricted use or are shelved for economic reasons in lieu of other options.

For example, autologous CAR T-cell therapies have demonstrated remarkable success, but manufacturing costs remain extremely high due to the large footprint and substantial clean room costs. Miniaturizing manufacturing and bringing it to the point-of-care setting could, potentially, benefit more patients at a lower cost to the healthcare system.

CAR T cells are just one example. Many processes that produce recombinant proteins use either mammalian or microbial cells and could reap cost savings if development and optimization at small scale better reflected that at scale-up or scale-out volumes. A promising resource, microbioreactors are just beginning to show their might as they become more sophisticated with integrated sensors and automation instrumentation.

A microbioreactor is a way of “doing more with less” succinctly stated Wei-Xiang Sin, PhD, research scientist at SMART CAMP. As these tiny growth machines become even more sophisticated with machine learning and AI algorithms they can only positively impact the future of biologics production.

Point-of-care manufacturing

Over a decade ago, Kevin Lee, PhD, and Harry Lee, PhD, and their colleagues in the MIT laboratory of Professor Rajeev Ram, PhD, developed the 2 mL “Breez” microbioreactor platform technology, which was subsequently spun out as Erbi Biosystems. In 2020 Millipore-Sigma, the U.S. and Canada Life Science business of Merck KGaA, acquired Erbi Biosystems and expanded their Mobius bioreactor portfolio.

“We have been working with the Breez since its development,” said Sin. Various designs of the microfluidic chip, ranging from 100 µL to 1 and 2 mL working volumes, have been used for microbial and mammalian cell culture applications.

“We thought that automated, closed-system microfluidic bioreactors might also be a novel production approach for the personalized nature of autologous cell therapies,” said Sin. Autologous cell therapy manufacturing has lengthy processes, with large equipment footprints, low production throughputs, the need for centralized cleanroom facilities, and a high cost of goods. “In particular, the perfusion-capable, modular Breez can support extremely high viable cell densities in a small volume and footprint,” continued Sin. The parallelized format, with four “pods” per system, allows up to four simultaneous runs per system to raise production throughputs and enable efficient scale out.

The 2 mL design was used to test human CAR T-cell production. Various timelines of activation and transduction as well as two different perfusion schemes, were evaluated to determine optimal conditions.¹ Minimal system modifications were made in this proof-of-concept study. Engineering improvements should help move the Breez closer to GMP compatibility on the way to potentially enabling decentralized, point-of-care manufacturing.

The small working volume could reduce the amount of GMP-grade viral vectors and reagents and thus the costs associated with CAR T-cell manufacturing. Importantly, the Breez has the smallest footprint (0.044 m2 per dose) compared to existing manufacturing methods, noted Sin. This attribute substantially decreases cleanroom fixed costs.

“The ability to make clinical-scale CAR T-cell doses in an extremely small form factor essentially means doing more with less—more production runs in parallel with less reagents, space, and manpower,” said Sin.

Better prediction and optimization

Many biological drugs are produced using mammalian cells. The process begins with cell line development (CLD) to determine which cell lines will produce the highest levels of recombinant proteins while maintaining stability during large-scale manufacturing.

According to Cheng-Han (Charles) Tsai, PhD, CEO at Cytena BPS, in the CLD workflow cell lines undergo incremental scaling of culture from static formats to shaker flask expansion and, eventually, to bioreactors. However, static formats lacking agitation technology face significant limitations. The size of multi-well plates and the cell numbers often restrict the ability to effectively agitate the culture, which in turn limits oxygen transfer and the overall culture environment. Microbioreactors offer small-scale, controlled culture environments that allow for better oxygen transfer and optimized cell growth conditions that can replicate the conditions needed for larger-scale bioreactors.

Currently focused on CLD applications, Cytena BPS’s microbioreactors provide precise control over culture conditions, enabling faster and more efficient cell line screening and optimization, according to Tsai, who adds that “additional applications include spheroid culture, stem cell/iPSC culture, long-term proliferation, metabolism and dynamic cellular behavior monitoring.”

The company’s C.NEST^® microplate agitation culture system is designed for high-throughput screening in 96- and 24-well plate formats. Customizable mixing intensities allow adjustment of the agitation levels according to the specific cell type and concentration improving oxygen transfer and environmental conditions. In addition, the S.NEST™ system incorporates sensors that provide real-time measurement of dissolved oxygen (DO) and pH to provide more accurate assessments of cell growth conditions to accelerate cell line development, improve process optimization, and efficiently evaluate cell culture health.

“Customers report that introducing mixing early has accelerated their scale-up processes, increased cell concentrations at each stage, and reduced the number of passaging steps,” said Tsai. Notably, the Cytena BPS workflow not only reduced a client’s CLD process time but also significantly increased cell viability in later-stage selection. “Facilitating tests at smaller scales while allowing for precise control of production parameters can permit better prediction and optimization of results before scaling up to larger production volumes,” he added.

Expediting screening

When contemplating the addition of microbioreactors to a workflow, Cristina Martija-Harris, product manager, Beckman Coulter Life Sciences, recommends evaluating usability, scalability, reproducibility, and reliability, as well as compatibility with existing data management and analysis tools. Suppliers can assist with a cost-benefit analysis to determine the economic viability of adoption.

The automated high-throughput BioLector XT Microbioreactor expedites the screening process for different microbial strains/clones, explained Martija-Harris. Applications are diverse including  food and beverage, microbiome studies, agriculture, and many aspects of academic, pharmaceutical, and biotech R&D.

The microbial screening platform allows users to design and execute sophisticated experiments that align with biological signals, enhancing scalability and reproducibility, Martija-Harris continued. Online measurements increase data reliability and robustness. In combination with the Biomek i5 Liquid Handler workstation the system permits individually triggered actions such as sampling, dosing of inducers or feed solutions, and inoculation of culture wells in a microtiter plate. “These actions are executed in response to real-time signals from the microbioreactor, including biomass, pH value, DO concentration, and experiment time without interruption to the shaking of the microtiter plate,” said Martija-Harris.

She pointed out that the BioLector XT Microbioreactor allows efficient clone selection along with problem solving during process development and optimization when there are many mutually influencing parameters.² The system utilizes a standard 48-well microtiter plate format that operates with online, pre-calibrated optical sensors for real-time measurement of cultivation parameters. Patented microfluidic technology facilitates concurrent pH control and feeding processes per cultivation well.

An optional Light Array Module (LAM) provides customizable light settings of 400-700 nm within the photosynthetic spectrum. Sixteen different LED-types can be controlled individually to deliver maximum irradiances and photon flux densities up to 3500 µmol/m2/s to support work with light-dependent organisms that require photosynthesis to grow, said Martija-Harris. “One of the standout features of the BioLector XT system is its strict anaerobic module, which is specifically designed to cultivate microorganisms that require an oxygen-free environment,” she explained.

By analyzing single-cell and spatial transcriptomic data from myeloid cells from 85 brain tumors, scientists from McGill University, the Broad Institute, and elsewhere found that a commonly prescribed anti-swelling drug, dexamethasone, suppresses the immune system for weeks after dosing, inhibiting its response to the cancer. The findings could open a door to more effective strategies for managing cancer-related inflammation in the brain as well as improved immunotherapies.

Full details were published in a Nature paper titled, “Programs, origins and immunomodulatory functions of myeloid cells in glioma.” In it, the researchers explain that they used single-cell and spatial data to learn how myeloid cells affect the immune system’s response to gliomas, tumors that develop in the brain or spinal cord. “In gliomas, myeloid cells are the most prevalent non-malignant cell type, comprising up to 50% of cells in a tumor,” the researchers wrote in Nature. “Tumor-associated myeloid cells can influence the molecular state of malignant cells as well as tumor-infiltrating T cells …. They can also recruit and suppress other myeloid cells.”

The study data revealed a consistent organization of cells within brain cancer, where each type of myeloid cell was found in specific areas and tailored to its role in the tumor. Notably, the researchers identified two types of immunosuppressive myeloid cells. In patients treated with dexamethasone, these specific cell types had a significantly higher immunosuppressive effect than those who had not been treated. And the effect was stronger as the drug dose increased.

Furthermore, when the scientists exposed myeloid cells that were categorized as non-immunosuppressive to dexamethasone, they found that these cells quickly became immunosuppressive following exposure. And the effect lasted a long time.

Research by scientists at the University of Southern California (USC) Leonard Davis School of Gerontology suggests that greater exposure to extreme heat may accelerate biological aging in older adults.

The study, which examined the association between ambient outdoor heat and epigenetic aging in thousands of individuals aged 56 years and older, raises new concerns about how climate change and heat waves could affect long-term health and aging at the molecular level.

Research lead Jennifer Ailshire, PhD, professor of gerontology and sociology at the USC Leonard Davis School, said people in neighborhoods that experience more days of high heat show greater biological aging on average than residents of cooler regions.

Ailshire is senior author of the team’s published paper in Science Advances, titled “Ambient outdoor heat and accelerated epigenetic aging among older adults in the US,” in which the team concluded, “These findings provide insights into the biological underpinnings linking heat to aging-related morbidity and mortality risks.”

Biological age is a measure of how well the body functions at the molecular, cellular, and system levels, as opposed to chronological age based on one’s birthdate. Having a biological age greater than one’s chronological age is associated with higher risk for disease and mortality.

“Global warming has intensified extreme heat events, posing serious risks to public health,” the authors wrote. “The frequency, intensity, and duration of extreme heat events are expected to grow rapidly in the coming decades, affecting more than 100 million Americans in 2050.” Exposure to extreme heat has long been associated with negative health outcomes, including cardiovascular diseases, and an increased risk of death, but the link to biological aging isn’t well understood.

Ailshire and co-author Eunyoung Choi, PhD, USC Leonard Davis School of Gerontology alumna and postdoctoral scholar, examined how biological age changed in more than 3,600 Health and Retirement Study (HRS) participants aged 56 years and older from throughout the United States. Blood samples taken at various time points during the six-year study period were analyzed for epigenetic changes, or changes in the way individual genes are turned off or on by a process called DNA methylation (DNAm).

“This study examines the association between heat and epigenetic aging in a nationally representative, diverse sample of older adults,” they explained. The effects on the body of heat events may not manifest immediately as clinical conditions, the investigators continued. “Rather, these environmental insults may elicit subclinical deterioration at the biological level, accelerating biological aging, which precedes the subsequent development of diseases and disabilities.” And while the effects of heat on DNAm have been reported across a number of different species, including fish, chickens, and some mammals, there have been very few studies in humans. “Our study bridges this gap by examining epigenetic age (or clock), a molecular marker of biological aging based on DNAm levels throughout the genome.”

To carry out their study the researchers used mathematical tools called epigenetic clocks to analyze DNA methylation patterns and estimate biological ages at each time point. They then compared participants’ changes in biological age to their location’s heat index history and the number of heat days reported by the National Weather Service from 2010 to 2016.

The National Weather Service Heat Index Chart categorizes heat index values into three levels based on the potential risk of adverse health effects. The “Caution” level includes heat index values ranging from 80°F to 90°F, the “Extreme Caution” level includes values between 90°F and 103°F, and the “Danger” level includes values between 103°F and 124°F. Days in all three levels were included as heat days in the study.

The analysis revealed a significant correlation between neighborhoods with more days of extreme heat and individuals experiencing greater increases in biological age, Choi said. This correlation persisted even after controlling for socioeconomic and other demographic differences, as well as lifestyle factors such as physical activity, alcohol consumption, and smoking, she added. “Our findings reveal significant associations between more heat days and accelerated epigenetic aging, particularly for longer-term periods,” the authors stated.

“Participants living in areas where heat days, as defined as Extreme Caution or higher levels (≥90°F), occur half the year, such as Phoenix, Arizona, experienced up to 14 months of additional biological aging compared to those living in areas with fewer than 10 heat days per year,” Choi commented. “Even after controlling for several factors, we found this association. Just because you live in an area with more heat days, you’re aging faster biologically.”

All three epigenetic clocks employed in the study—PCPhenoAge, PCGrimAge, and DunedinPACE—revealed this association when analyzing epigenetic aging over a 1- to 6-year period. “We found consistent associations between long-term heat days and accelerated epigenetic aging across PCPhenoAge, PCGrimAge, and DunedinPACE,” the investigators noted. PCPhenoAge also showed the association after short (7 days) and medium (30–60 days) periods of time, indicating that heat-related epigenetic changes could happen relatively quickly, and some of them may accumulate over time. “Specifically, we observe that short-and mid-term heat conditions are significantly associated with increases in PCPhenoAge, while more heat days more than 1 year and 6 years are linked to accelerated epigenetic aging in all epigenetic clocks,” they added.

Older adults are particularly vulnerable to the effects of high heat, Ailshire said. She noted that the study used heat index, rather than just air temperature, to take relative humidity into account as they analyzed results.

“It’s really about the combination of heat and humidity, particularly for older adults, because older adults don’t sweat the same way. We start to lose our ability to have the skin-cooling effect that comes from that evaporation of sweat,” she explained. “If you’re in a high humidity place, you don’t get as much of that cooling effect. You have to look at your area’s temperature and your humidity to really understand what your risk might be.”

The next steps for the researchers will be to determine what other factors might make someone more vulnerable to heat-related biological aging and how it might connect to clinical outcomes. “Our study provides insights into the biological underpinnings linking heat to the broader spectrum of aging-related morbidity and mortality risks,” they wrote. “We demonstrated that short-, mid-, and long-term ambient outdoor heat can significantly accelerate epigenetic aging within a diverse, nationally representative cohort of older adults.”

In the meantime, the study results could also prompt policymakers, architects, and others to keep heat mitigation and age-friendly features in mind as they update cities’ infrastructure, from placing sidewalks and building bus stops with shade in mind to planting more trees and increasing urban green space, Ailshire said. The findings, the investigators noted in their report, provide “strong evidence critical for guiding public policy and advocacy initiatives aimed at developing mitigation strategies against climate change.”

Ailshire added, “If everywhere is getting warmer and the population is aging, and these people are vulnerable, then we need to get really a lot smarter about these mitigation strategies.”

The authors further concluded, “… our findings serve as a foundation for the development of targeted public health interventions, providing a strategic framework for addressing the adverse biological impacts triggered by extreme heat.”

he FDA has granted Priority Review to Precigen’s Biologics License Application (BLA) for its lead candidate PRGN-2012, the company said—a step forward for a gene therapy that, if approved, would be the first treatment indicated for adults with the rare disease of recurrent respiratory papillomatosis (RRP).

The FDA also set an August 27 target date for deciding on Precigen’s BLA under the Prescription Drug User Fee Act (PDUFA). PRGN-2012—which Precigen has begun to call by its generic name of zopapogene imadenovec—is a gene therapy designed to elicit immune responses directed against cells infected with human papillomavirus (HPV) 6 or HPV 11.

Infection with HPV 6 or HPV 11 causes RRP, a lifelong neoplastic disease of the upper and lower respiratory tracts that can be fatal. According to Precigen, some 27,000 U.S. adults have RRP based on a recently updated internal analysis derived from claims data, and more than 125,000 patients outside the United States have the disease. The standard of care for RRP patients consists of numerous surgeries.

Precigen has projected a “multi-billion-dollar global blockbuster potential” for PRGN-2012. The publicly traded company has not guided investors to a projected list price for the gene therapy, though president and CEO Halen Sabzevari, PhD, told GEN Edge recently that the company has focused on late clinical development and eventual commercialization of PRGN-2012 since the summer.

In July, Precigen announced the appointment of Phil Tennant as chief commercial officer, with initial duties focused on overseeing commercial readiness activities for the potential launch of PRGN-2012.

“We have been basically building our commercial force, and have Phil’s leadership of the commercial effort that he has already assembled, and we feel that we will be ready to launch immediately after the FDA approval,” Sabzevari said.

That effort, she added, will entail Precigen teaming up with partners experienced in commercial activity who will report directly to the company’s commercial force: “It will be completely under our control. We believe that that would be the fastest way for us and also more effective, instead of just building every unit directly from inside.”

Precigen declared the advancement of PRGN02012 its first priority when it reprioritized its clinical portfolio and resources last August, in the process eliminating over 20% of its workforce. Precigen now has about 100 jobs, though the company plans to add some executives in strategic positions, especially in commercial medical affairs, “to address the needs that we have for PRG in 2012 at this moment,” Sabzevari said.

60% surge

Investors appeared to warm up slowly to the news on PRGN-2012, as Precigen shares Tuesday dipped 1% from $1.75 to $1.73, before climbing 6% to $1.84 in early Tuesday trading as of 11:38 am ET. Precigen’s shares have surged 60% over the past six months, climbing from $1.15 on August 26, 2024, as the company has shared a series of positive updates on the clinical development of PRGN-2012 and its other pipeline candidates.

PRGN-2012 was developed through the company’s AdenoVerse® platform, which uses a library of adenovectors for efficient gene delivery of therapeutic effectors, immunomodulators, and vaccine antigens designed to modulate the immune system. Precigen said its AdenoVerse gene therapies have been shown to generate high-level and durable antigen-specific T-cell immune responses, as well as boost these responses via repeat administration.

Single-cell RNA sequencing has established itself as one of the most important technologies for studying the transcriptome of individual cells at high resolution. One area where it is making a difference is in the understanding of retinal ganglion cell (RGC) loss in optic neuropathies like glaucoma. Effective strategies for retinal repair and regeneration in these cases are lacking in part because developmental programs required for cell differentiation and maturation are not fully understood. Recently, scientists successfully used cellular reprogramming to regenerate human RGC neurons that demonstrated transcriptional profiles and functional properties characteristic of healthy RGCs. Single-cell RNA sequencing played a pivotal role in confirming the identity of the reprogrammed cells and in revealing the diversity of RGC subtypes.

In the first presentation of this GEN webinar, our expert speaker will present results from the study and how they generated RGC-like induced neurons in under a week by combining the pioneer factor NEUROG2 with RGC-specific TFs, and pre-patterning cells via BMP inhibition. During the webinar, you’ll learn how the particle-templated instant partition sequencing (PIP-seq) technology from Illumina was crucial for identifying and classifying over 30 RGC subtypes. In the second presentation, you’ll hear the results from a third-party case study that compared the performance of Illumina Single Cell with the newest 10X Genomics assay on two different cell types.

Working toward more effective tuberculosis (TB) vaccines, researchers at Weill Cornell Medicine have developed two strains of mycobacteria with “kill switches” that can be triggered to stop the bacteria after they activate an immune response. Two preclinical studies, published Jan. 10 in Nature Microbiology, tackle the challenge of engineering bacteria that are safe for use in controlled human infection trials or as better vaccines. While TB is under control in most developed countries, the disease still kills over a million people a year worldwide.

Spreading easily through the air, Mycobacterium tuberculosis can establish a chronic infection in human lungs, which can turn into a deadly respiratory disease. A safe vaccine called BCG, consisting of a weakened strain of the closely related Mycobacterium bovis, has been available for over a century but has limited efficacy.

“BCG protects children from tuberculosis meningitis, but it doesn’t effectively protect adults from pulmonary tuberculosis, which is why it’s only used in high-incidence countries,” said Dr. Dirk Schnappinger, professor of microbiology and immunology at Weill Cornell Medicine and a senior author on both of the new studies.

However, collaborators at the University of Pittsburgh and the National Institutes of Health’s Vaccine Research Center previously found that administering high doses of the BCG vaccine directly into the veins, instead of the usual route of giving it under the skin, was better at protecting adult macaque monkeys against lung infection.

Building a better vaccine

In one of the new papers, the team aimed to make this high-dose intravenous injection safer, without destroying the vaccine’s ability to stimulate a strong immune response. “We needed a version of BCG that triggers an immune response, but then you can flip a switch to eliminate the bacteria,” said Dr. Schnappinger.

After testing about 20 different strategies, the investigators found that lysins, enzymes encoded by viruses that can infect BCG, cause the bacteria to self-destruct. Using a clever bit of molecular engineering, they placed two different lysin genes under the control of gene regulators that respond to an antibiotic. By adding or taking away the antibiotic, they could then flip the kill switch.

A new combination of microscopy methods has revealed exquisite detail of the virus assembly process used by herpes simplex virus during replication.

The research, published today in eLife, is described by the editors as a fundamental study that comprehensively examines the roles of nine structural proteins in herpes simplex virus 1 (HSV-1) viral assembly. They say the thoroughly executed research yields compelling data that explain previously unknown functions of HSV-1 structural proteins.

Additionally, by integrating cryo-light microscopy and soft X-ray tomography, it presents an innovative approach to investigating viral assembly within cells that will be of broad interest to virologists, cellular biologists and structural biologists.

HSV-1 is a large virus that infects the mucous membranes of the mouth and genitals, causing life-long latent infections. The virus is composed of three layers—a capsid that contains the viral DNA, a protein layer called the tegument and an outer envelope that is studded with viral glycoproteins (proteins with a sugar attached). During replication, newly copied viral genomes are packaged up into this three-layer structure in a process called viral assembly.

While some drugs can block the virus’ DNA replication and alleviate symptoms, there is no permanent cure. A deeper understanding of the assembly process could inform the design of novel treatments or cures that inhibit virus formation.. But until now, pinpointing the role of different HSV-1 components in the viral assembly process has proved challenging.

“HSV-1 mutants that cannot make certain proteins have been used to study the role of viral genes in virus assembly, using a method called thin section transmission electron microscopy, or TEM,” says lead author Kamal Nahas, Beamline Scientist at Beamline B24, Diamond Light Source, Harwell Science & Innovation Campus, Didcot, U.K. “However, the extensive sample processing required for TEM can distort the microscopic structure and complicate the interpretation of features in viral assembly.”

Viral assembly involves a multi-step process, starting in the cell’s nucleus with assembly of capsids, packaging of the DNA to form “nucleocapsids,” and transport of these nucleocapsids out of the nucleus via a process of primary envelopment and de-envelopment to travel across the nuclear envelope. This is followed by a secondary envelopment in the cellular area surrounding the nucleus, called the cytoplasm (cytoplasmic envelopment).

Imaging methods that maintain the HSV-1-infected cells as close to physiological conditions as possible are needed to fully understand this complex, three-dimensional (3D) assembly process.

The authors used an emerging 3D imaging approach to study the envelopment mechanism and investigate the importance of different HSV-1 genes for viral assembly by investigating the impact of specific mutations of these viral genes. Their new approach combined two methods—cryo-structured illumination microscopy (cryoSIM) to detect fluorescently labeled capsid or envelope components, and cryo-soft-X-ray tomography (cryoSXT) to identify the cellular substructure in the same infected cells.

Together, this “correlative light X-ray tomography” (CLXT) approach makes it possible to identify specific structural components within the viral assembly process, allowing the team to visualize exactly where the assembly process stalls for each mutant virus, and providing insights into the unmutated gene’s usual role in viral assembly.

The authors captured different assembly stages during cytoplasmic envelopment using their mutant viruses and showed that—contrary to previous theories—cytoplasmic envelopment is caused by the budding of a capsid into an intracellular membrane “sack” or vesicle, and not by the capsid being “wrapped” by the vesicle membrane.

A further new finding is that this budding is asymmetric; the team observed several instances of stalled viral assembly where groups of capsids were gathered at one region, or side, of a spherical vesicle.

Using their CLXT approach, they were able to rank the relative importance of five of the mutant viral proteins in the process of nuclear egress. They were also able to reveal the role of a further five viral proteins in the cytoplasmic envelopment stage. For example, a protein called VP16 was found to be important in delivering the capsid to envelopment compartments and is now thought to have a larger role in nuclear egress than previously thought. In addition, the new method revealed that the absence of four other proteins caused virus particles to build up in the cytoplasm where assembly had stalled.

“Our multi-modal imaging strategy has provided novel ultrastructural insight into HSV-1 assembly, allowing the assembly trajectory of normal and mutant viruses to be observed in 3D,” concludes senior author Colin Crump, Professor of Molecular Virology at the University of Cambridge, U.K. “Our data underscore the power of correlative fluorescence and X-ray tomography cryo-imaging for interrogating and conducting further studies on the process of virus assembly.”