by Charlotte Kilpatrick | Oct 1, 2024 | Therapeutic |
In an article for npj vaccines in October 2024, researchers present their investigation into the efficacy of a combination of DNA vaccine encoding mouse GPRC5D and PD-1 in preventing and treating multiple myeloma (MM). MM “remains largely incurable”, but the GPRC5D, “highly expressed” in MM, presents a “compelling” immunotherapy candidate. The research suggests that GPRC5D-targeted DNA vaccines are “versatile platforms” for treating and preventing MM.
Managing MM
Multiple myeloma (MM) is the second most prevalent haematological malignancy, characterised by the accumulation of malignant plasma cells in bone marrow. Most MM cases are preceded by monoclonal gammopathy of undetermined significance (MGUS), which can reduce a person’s life expectancy by “more than 4 years”. Around 3.5 million people are affected by MGUS in the United States. Smouldering MM (SMM), distinguished from MGUS for clinical reasons, is an asymptomatic clonal plasma cell disorder between MGUS and MM.
MM treatment has been “transformed with the advent of antibody-based therapies”, with chimeric antigen receptor (CAR) T-cell therapies that target the B-cell maturation antigen (BCMA) showing “considerable promise”. However, the pattern of BCMA expression is heterogeneous, responsible for “varied treatment responses” and the surface expression can “fluctuate” because of gamma secretase-mediated shedding of the extracellular domain. Furthermore, antigen escape has been noted in patients with MM who experienced relapse after BCMA-targeted CAR T-cell therapy.
“Exploring immunotherapies targeting alternative antigens may help counteract antigen escape and provide effective treatment options for patients who relapse after BCMA-targeted CAR T-cell treatment.”
A new vaccine target
C protein-coupled receptors (GPCRs) are the “largest and most diverse” group fo membrane receptors in eukaryotes; humans have almost 1000 different GPCRs. GPCRs are classified into six classes (A-F), among which class C GPCRs initiate metabolic steps to modulate cellular activity.
Orphan GPCR class C group 5 member D (GPRC5D) is expressed in the hair follicle and the bone marrow of patients with MM, as well as in MGUS and SMM. The GPRC5D mRNA is overexpressed between two and four times in MM plasma cells compared to normal plasma cells, and immediate expression is seen in MGUS and SMM.
“GPRC5D is an emerging novel immunotherapeutic and preventive target for MM.”
Although DNA vaccines are a “promising” alternative to mRNA vaccines, with “lower cost and better stability”, they have not yet been widely adopted in clinical practice. DNA cancer vaccine development faces “significant challenges” such as nonspecific formulations, thermal instability, toxicity, and ineffectiveness. However, the authors believe that recent advancements have “greatly enhanced” the clinical efficacy of DNA vaccines in cancer treatment.
The study
In their research, the authors attempted to develop DNA vaccines against MM using plasmids expressing GPRC5D. First, they evaluated a mouse GPRC5D DNA vaccine in the 5TGM1 murine myeloma model, which “closely mimics” human MM. Cancer prevention activity was examined through administration of the DNA vaccine before tumour cell inoculation. The mice that received the mGPRC5D vaccine developed “significantly smaller” tumours than the control mice, and all animals in the mGPRC5D group were alive at day 33.
With ELISA, the authors evaluated the humoral response by measuring the levels of mGPRC5D-specific antibody in the serum collected 5 days after boost. They found a “marked increase” in serum IgG levels in the mGPRC5D group. To explore the possible mechanisms of the antitumour effect of the vaccine, they analysed immune cells in the spleen and tumours through flow cytometry. The percentage of various immune cell populations “significantly increased” in the mGPRC5D-immunised mice.
The research also considered the therapeutic efficacy of the mGPRC5D vaccine in combination with PD1 Ab treatment. After tumour inoculation, mice received two injections of 20µg mGPRC5D vaccine or the control plasmid at 2-week intervals, along with intraperitoneal administration of anti-PD1 antibody. Mice that received either the vaccine or anti-PD1 Ab showed a “moderate inhibitory effect”, but those treated with the combination exhibited “significant inhibition of tumour development”.
When comparing tumour weights in mice, the authors found “significantly” lower weights in the mGPRC5D and PD1 Ab group than in the control group or each monotherapy group. They also assessed the ability of the vaccine to induce TNFα or IFNγ responses in mouse splenocytes with the ELISPOT assay. Splenocytes from mice that received either mGPRC5D or PD1 Ab exhibited a “significant” increase in the number of spots, and a further increase was observed in the group that had the combination. The combination group had higher frequencies of TNFα+CD8+, IFNγ+CD8+, TNFα +CD4+, and IFNγ+CD4+ T cells in the spleen.
In a flow cytometric analysis of immune cell populations in the spleen, the authors found that treatment with mGPRC5D increased the frequency of CD4+ T cells by over 150% and CD8+ T cells by over 30%. PD1 Ab treatment increased the frequency of both cells by more than 100%. The combination had a “more pronounced effect”; CD4+ T cells increased more than 350% and CD8+ T cells increased by more than 130%. Similar observations were made for DCs, Mϕ, and NK cells in the spleen. For tumour-infiltrating lymphocytes (TILs), the combination approach increased the population of CD8+ and CD4+ T cells, DCs, Mϕ, and NK cells more than the monotherapies.
A human vaccine
As the peptide sequences of mGPRC5D and hGPRC5D are only ~81% identical, a human version of the vaccine is needed. The researchers developed a nanoplasmid construct expressing human GPRC5D (Nano-hGPRC5D). Prophylactic studies found that tumour growth was “significantly suppressed” in the mice group that received Nano-hGPRC5D, which also presented a “marked increase” in serum IgG levels. Other findings include a “significant increase” in the levels of cytokines in the Nano-hGPRC5D group, which suggests a “robust activation of inflammatory cytokines” upon vaccination.
In the spleen and tumours of hGPRC5D-immunised mice, percentages of CD3+, CD4+, and CD8+ T cells and DCs were “significantly increased”. Furthermore, higher frequencies of Th1 secretory cytokine-positive CD3+ T cells were observed in this group. A long-acting protective effect against tumours was implied in “significantly higher percentages” of effector and central memory T cells in the splenocytes of the hGPRC5D group. CD8+ T cells stimulated with the hGPRC5D peptide pool exhibited “superior proliferative ability” compared to the control.
Therapeutic combination
To evaluate the therapeutic efficacy of Nano-hGPRC5D in combination with PD1 Ab, the authors used syngeneic murine models. The combination resulted in “significant tumour regression” compared to either treatment alone. Levels of TNFα, IFNγ, IL-6, IL-12p40, and IL-12p70 increased “significantly” in the combination group, and ELISpot analysis revealed more TNFα- or IFNγ-positive cells in the combination group.
In a flow cytometric analysis of immune cell populations in the spleen and tumour, the combination caused an increase in effector CD8+ and CD4+ T cells, DCs, Mϕ, and NK cells, but a decrease in Treg cells. H&E staining of tumour sections revealed necrotic lesions in the hGPRC5D and combination groups, but the lack of gross histological damage in several major organs supports the safety and clinical potential of the vaccine or combination.
Analysis of the immune cells revealed a “marked increase” in CD3+, CD8+, and CD4+ T cells in the splenic marginal zones of the combination group, consistent with flow cytometry data. There was also an increase in B lymphocytes and follicular DCs in this group. For TILs, the combination therapy also increased the number of CD8+ and CD4+ T cells.
Improving outcomes
Despite therapeutic advancements, high-risk patients with MM “continue to have poor outcomes”, and there are limited agents to prevent MM or progression from MGUS and SMM. The results from the study suggest that PD1 blockade “enhances tumour growth inhibition” in mice treated with the DNA vaccine and highlight the potential of the DNA-based GPRC5D vaccine to “overcome self-tolerance and the prospects of advancing” into clinical trials.
For the latest on cancer vaccine development and combination approaches to disease control, join us at the Congress in Barcelona next week. Don’t forget to subscribe to our weekly newsletters for more vaccine updates.
by Charlotte Kilpatrick | Sep 19, 2024 | Technology |
An article in Scientific Reports in September 2024 uses Digital Shadows to facilitate a comparison of recombinant DNA and in vitro (IVT) mRNA vaccine manufacturing technologies. The authors offer an assessment of which manufacturing platform is better suited for two types of vaccines. They suggest that recombinant DNA technology exhibits a higher Profitability Index, but mRNA offers faster high potency in short product development cycles.
Technical and economic benefits
Limitations in “traditional vaccines” have “speared” the development of novel technologies for antigens and monoclonal antibodies, including the recent use of recombinant DNA and RNA technologies in the COVID-19 pandemic. Recombinant DNA technology requires the insertion of a gene encoding the relevant pathogen or immunoglobulin sequence into a cell factory organism, which produces the antigen or antibody. RNA technology uses stoichiometric biochemical reactions to produce mRNA (messenger RNA) encoding the antigen or antibody, which is translated in vivo by the recipient’s cells.
Both mRNA and DNA technologies have “established proof of therapeutic effectiveness”. However, they differ in approach to obtaining the therapeutic protein of choice, which leads to different manufacturing processes. For recombinant DNA, the process is “time-consuming and expensive, requiring specialised laboratory facilities and trained personnel”. By contrast, IVT mRNA is understood to be “fast, flexible, and inexpensive”. This is offset by the need for cold transportation and storage to cater to the “instability and sensitivity” of the RNA molecule. Furthermore, IVT mRNA-based vaccine manufacturing has not been standardised.
Both technologies have “captured the global scientific interest” and present opportunities in the treatment of cancer and autoimmune diseases among others. However, the authors state that that there is no comparison of the two technologies on technical and economic levels.
The study
Digital Shadows are “enabling tools suitable to model a system in a fiat cyber-physical environment, delivering data flow abstractions of processing performance”. They are also used in the study to simulate and analyse the “technical merits and production costs” of each technology at given operating conditions. This allows the researchers to investigate root cause deviations and evaluate the cost-effectiveness scenarios of each proposed solution.
The authors constructed Digital Shadows to compare recombinant manufacturing of monoclonal antibodies and antigens with IVT mRNA production processes. They developed algorithmic threads to explore strengths and weaknesses, offering “enabling tools of strategic decision planning”.
The research suggests that recombinant production methods create “highly stable and therefore advantageous products”, with a proven track record of clinical safety and efficacy, and a low risk of unknown side effects, carrier-related allergic reactions, and withdrawals. The vaccines require “minimal maintenance” to preserve stability and functionality, which “ameliorates any respective logistical challenges and minimises the risks related to post-production regulatory withdrawals”. The components needed for production are “accessible” for the pharmaceutical industry but may come under pressure in case of pandemic outbreaks.
A drawback of the recombinant DNA vaccine production platform is its “complicated and therefore difficult-to-automate sub-processes”. The technology requires additional personnel for “process supervision and control purposes”. The platform is therefore “less appropriate for encountering pandemic bursts” or tracking mutations.
Another concern is the high risk of material contamination in cellular protein production, particularly in upstream processing. If contamination occurs, the cell line and its products are discarded, which causes delays and financial losses. Alongside this risk, recombinant DNA and protein production methods feature “low production yield”, which means that raw and side materials are purchased at high quantities and handled by expert personnel to reach the necessary production capacity.
IVT mRNA manufacturing protocols have “strong competitive advantages” in some characteristics. Although the vaccine is “highly sensitive to environmental conditions”, the production process is “easier to standardise, automate, adapt, and operate in continuous mode” thanks to the synthetic chemical nature of its sub-processes. The biochemical section of related processes can offer a “less complex, more effective” alternative with minimal requirements. This reduces the risks of cross contamination and quality-related batch rejections, producing higher yields and limiting product losses; it also lowers raw material processing resources and reduces development time.
Conclusions
For monoclonal antibody products, the study showed that recombinant DNA technology had a higher Profitability Index than IVT mRNA manufacturing. While the recombinant DNA monoclonal antibodies require a significantly higher dose due to an inferior potency profile, this is not reflected analogously in the final production cost. IVT mRNA manufacturing also had “higher dependencies” on raw materials.
When considering antigenic vaccines, the authors found that recombinant DNA technology demonstrated “higher economic performance”, demanding reduced capital resources. It also encompasses “proven, well-grounded protocols” for process development. Recombinant manufacturing “appears advantageous” by meeting technical and financial expectations. However, IVT mRNA “significantly” shortens the timeline from development to clinical application and benchtop to scale manufacturing. It also offers “unparalleled advantages” in synthetic processes and reduced requirements for installing large-scale production equipment.
The paper concludes that clinical trials and field practice will reveal if mRNA technologies can offer non-inferior therapeutic results compared to their DNA recombinant established alternatives. If you have worked with either of these technologies, what are your impressions or predictions? Why not join us at the Congress in Barcelona next month to share your insights into various platform technologies, and don’t forget to subscribe to our weekly newsletters for the latest vaccine news.
by Charlotte Kilpatrick | Sep 18, 2024 | Technology |
PharmaJet announced in September 2024 that it has entered a long-term license and supply agreement with Scancell Holdings to use PharmaJet’s Stratis Intramuscular (IM) Needle-free System for the delivery of its advanced melanoma DNA vaccine. Through the agreement, Scancell will use Stratis for the clinical development and commercialisation of ImmunoBody, the advanced melanoma DNA vaccine. PharmaJet will receive development and regulatory milestone payments and royalties on net sales upon commercialisation.
Stratis
PharmaJet’s Stratis technology is a needle-free system for 0.5 ml intramuscular and subcutaneous injections that enhances the performance of nucleic acid vaccines and therapeutics. Stratis delivery has demonstrated the ability to enable “effective uptake” of the Scancell DNA melanoma vaccine; 60 patients across 15 clinical trial sites have received a total of 171 doses of SCIB1/iSCIB1+ through Stratis. This approach offers the “convenience of an off-the-shelf therapeutic cancer vaccine with the speed and enhanced patient experience of needle-free delivery”.
ImmunoBody vaccines
Scancell’s ImmuoBody vaccines are designed to generate “potent” T cell responses that provide a broad anti-tumour effect. They are DNA vaccines that encode a protein in antibody form, with the elements of the antibody that would normally bind to the target protein replaced with cancer antigen epitopes. ImmunoBody vaccine design features include:
- Epitopes that bind to MHC class I and MHC class II
- Retention of the Fc region of the protein, which targets activated dendritic cells via its specific receptor
However, Scancell highlights the “most important aspect” of the technology as the ability to initiate both direct and cross-presentation of epitopes to T cells. The “highest avidity T cell responses” are generated if different pathways are used to present the same epitope. In ImmunoBody, the DNA form is taken up and processed directly by dendritic cells and the protein form binds to the high affinity Fc receptor on dendritic cells, leading to cross-presentation.
Advancing innovation
Professor Lindy Durrant, Chief Executive Officer of Scancell, is pleased that PharmaJet delivery “works effectively” with the SCIB1/iSCIB1+ vaccines and offers a “well-received immunisation for patients”.
“Securing long term supply for the PharmaJet Stratis Needle-free Injection System is important to allow clinical and commercial development of iSCIB1+…Our ultimate goal for Scancell has been to deliver an off-the-shelf, safe, tolerable, effective therapy that can provide potent and durable anti-tumour responses for unresectable stage IV melanoma, which currently has a 5-year survival of 35%.”
PharmaJet’s Chief Scientific Officer, Nathalie Landry, looks forward to working with Scancell to “advance their innovation further in clinical development and commercialisation” with benefits for melanoma patients.
“The Scancell strategic partnership further solidifies PharmaJet’s commercial delivery platform as a leader in the delivery of nucleic acid vaccines and immunotherapies.”
For more on PharmaJet’s needle-free delivery technology, join us at the Congress in Barcelona next month. Don’t forget to subscribe to our weekly newsletters for regular vaccine updates.
by Charlotte Kilpatrick | Aug 27, 2024 | Technology |
CEPI announced in August 2024 that it is providing US$2.05 million to researchers at Afrigen Biologics to support their work on synthetic DNA. The scientists are exploring if it can act as an alternative to the “traditional” plasmid DNA required for mRNA vaccines, thus accelerating the initial phase of vaccine development. The partnership supports CEPI’s 100 Days Mission by seeking to make vaccine development “up to three time faster”.
Optimised synthetic DNA
Plasmid DNA (pDNA) is traditionally used in mRNA vaccines as the “start material” containing genetic instructions to produce a specific viral protein. pDNA is produced through bacterial fermentation, which can take over 30 days.
“This process is time-consuming and expensive, and timelines can be further compounded by insufficient manufacturing capacity and supply chain issues.”
A potential alternative is optimised synthetic DNA (oDNA), manufactured by Syngoi. It is produced by enzymes in a cell-free process that demands a smaller manufacturing footprint, can be rapidly produced in just 10 days, and is less costly. The proof-of concept project between CEPI and Afrigen will explore this technology by using pDNA and oDNA to develop and mRNA vaccine for Rift Valley Fever.
“If successful, the oDNA technology could accelerate the production of clinical trial material required to test new mRNA vaccines in human clinical trials and ultimately make vaccines available more swiftly to those most in need.”
Prioritising equity
Ingrid Kromann, Acting Executive Director, Manufacturing and Supply Chain, CEPI, commented that mRNA vaccine manufacturing processes are “fast and flexible”.
“Innovative technologies like optimised synthetic DNA can make them even faster. CEPI’s partnership with Afrigen could reduce the vaccine development timelines by addressing the challenges associated with plasmid-DNA supply, helping get vaccines to people faster in the face of an outbreak and reduce inequity.”
As the WHO/Medicines Patent Pool Hub for mRNA Technology Transfer Programme, Afrigen acts as a centre of excellence and training for the initiative, seeking to build mRNA vaccine production capacity in low- and middle-income countries. This new partnership could enable local manufacturing of vaccines in Africa, supporting CEPI’s strategy to “geo-diversify” global manufacturing capabilities. Professor Petro Terblanche, Afrigen CEO, described the partnership as a “strategic milestone” that demonstrates the “important contribution that biotechnology start-up companies can make to innovation”.
“We are enthusiastic about the contribution this joint project can make to the speed and cost of mRNA vaccine manufacturing.”
We look forward to hearing more on regional capacity for equitable vaccine distribution from Professor Terblanche at the Congress in Barcelona this October; get your tickets to join us here and don’t forget to subscribe to our weekly newsletters here.
by Charlotte Kilpatrick | Aug 21, 2024 | Technology |
In August 2024 Touchlight announced that it is supplying its proprietary dbDNA to the University of Nottingham in support of the research and development of a next-generation DNA vaccine targeting Zika virus. The scientists at University of Nottingham are working on a Zika virus DNA vaccine that could be manufactured “within weeks” and deployed globally in future epidemics. While many DNA vaccines in development require devices to deliver the vaccine through the skin, the Nottingham researchers have identified a solution. Their proprietary DNA formulation can be given by a simple injection and uses synthetic manufacture instead of bacterial fermentation, shortening development time from 6 months to 6 weeks.
Rapid, efficient, scalable
Touchlight states that its enzymatic dbDNA technology represents a “breakthrough” in DNA production, offering a “rapid, efficient, and scalable” method for vaccine development. The dbDNA has the potential to reduce dose, eliminate antibiotic resistance, and provide a solution for low cost, stable vaccines for the developing world. Named after its schematic structure, doggybone DNA (dbDNA) is a “minimal, linear, double stranded, and covalently closed DNA construct”. It can encode long, complex, or unstable DNA sequences and has a “strong” expression profile.
DNA vaccines
DNA vaccines can be produced “rapidly and cheaply” and don’t require the same cold-chain storage as mRNA vaccines. Therefore, DNA vaccines are “ideal” for outbreak responses, particularly in “less economically developed regions”. The project has been funded by the UK Department of Health and Social Care, within the UK Vaccine Network, which aims to develop vaccines for disease with epidemic potential in low- and middle-income countries.
University of Nottingham’s Dr James Dixon commented that the Touchlight technology “has enabled us to make rapid progress” and will allow the team to “produce large quantities of the DNA vaccine at speed”. This is “vital in pandemic prevention and our response to the deployment of vaccines in the developing world and globally”.
“It will be hugely exciting to complete the pre-clinical trials and take us into the final stages with clinical trials and seeing real-world impact.”
Touchlight Chief Operating Officer Dr Tommy Duncan is “thrilled” to support the team at Nottingham with “innovative dbDNA technology”.
“We are committed to enabling developers of DNA vaccines by providing rapid, high purity DNA for vaccines against emerging pathogens.”
We look forward to welcoming Touchlight to the Congress in Barcelona this October; get your tickets to join us there and don’t forget to subscribe to our weekly newsletters for vaccine updates.
by Charlotte Kilpatrick | Jul 11, 2024 | Technology |
Seattle-based biotech Orlance announced in July 2024 that it has been awarded a Phase I Small Business Innovation Research (SBIR) grant from the US NIH to develop and optimise RNA vaccine formulations with its needle-free MACH-1 platform. The technology is intended to enhance the safety, stability, and efficacy of RNA vaccines for infectious diseases and cancer immunotherapy applications. MACH-1 is described as a “potentially significant advancement” in RNA vaccine delivery.
Meet MACH-1
MACH-1 is a needle-free vaccine platform that provides a “rapidly deployable, ambient stable, dose sparing, and easy to use product”. Orlance hopes it will increase immunisation in underserved regions by overcoming logistics or personnel difficulties and needlestick hesitancy. With pressurised gas, MACH-1 accelerates microparticles of DNA vaccines, RNA vaccines, or a combination. Vaccine microparticles penetrate the outer layer of skin to reach the epidermal layer, achieving intracellular delivery and transfection in local antigen presenting cells within the epidermis. This results in “robust” induction of systemic and mucosal antibody and cytotoxic T cell responses.
Compared to traditional lipid nanoparticle (LNP) RNA formulations, the MACH-1 platform uses dry, stable RNA-coated gold microparticles. It is needle-free and painless and ensures better stability at ambient temperatures with “significant supply chain advantages”.
Gene Gun project
The SBIR-funded project, “Gene Gun-delivered RNA vaccines”, is to be led by Orlance Principal Investigators Dr Hannah Frizzell and Dr Kenneth Bagley. They will aim to optimise RNA formulations for MACH-1 gene gun delivery to “maximise loading, maintain functional integrity, and ensure stability and immunogenicity”. The researchers will compare the effectiveness of MACH-1 delivered RNA vaccines against traditional LNP/RNA vaccines.
The 2-year grant provides $300,000 a year to enable Orlance to conduct preclinical studies, expected to “pave the way” for subsequent phases of development. Orlance has already received $13 million in SBIR funding, advancing MACH-1 towards readiness for initial regulatory filings in 2024. The company plans to initiate Phase I clinical trials for its lead infectious disease asset in 2025.
Kristyn Aalto, co-founder and CEO of Orlance, stated that the “breakthrough” of mRNA vaccines in recent years has “established the enormous potential of genetic (RNA and DNA vaccines”. However, there is still “significant work to do to improve utility and overall global health impact”.
“We are very grateful for NIH’s continued support and are rapidly accomplishing MACH-1 platform goals that could truly enhance the clinical research and impact of genetic vaccines.”
With a “well-developed” candidate portfolio and offerings across both DNA and RNA, Aalto hopes to “leverage the attributes of both platforms to provide ideal solutions tuned to the immunogenicity, protection, and durability profiles sought for specific indications”.
To hear the latest on innovative vaccine delivery approaches, why not join us in Barcelona for the Congress this October, or subscribe to our weekly newsletters here?
by Charlotte Kilpatrick | Mar 18, 2024 | Therapeutic |
In March 2024 researchers at Wyss Institute announced the publication of research that indicates the possibility that DNA origami could serve as a platform for “controlling adjuvant spacing and co-delivering antigens in vaccines”. Their platform, DoriVac, enables the “precise spacing and geometrical arrangement of molecules” on nanoparticles to produce “highly effective and personalised immunotherapies”. Developed in collaboration with Dana-Farber Cancer Institute, Harvard Medical School, and Korea Institute of Science and Technology, the platform is intended to overcome several “problems” associated with cancer immunotherapy.
Identifying a need
Wyss Institute comments that “serious diseases” such as cancer and autoimmune conditions demand “multiple drugs”. However, combining drugs is “challenging” for several reasons, including toxicity. This occurs when the side effects of multiple drugs “compound each other” to produce “much greater patient suffering”. Furthermore, drug combinations can lead to “increased costs for patients and insurers”.
The team specifically address the problem in personalised immunotherapy, where both tumour antigens and adjuvants need to be presented to antigen-presenting cells (APCs).
“It is yet unknown how these molecules might interact with each other when co-delivered, or how to optimise the process and the dosages to produce the strongest anti-cancer response.”
Enter DoriVac
DoriVac is a DNA origami platform that has identified “molecular patterns” to produce “superior immune responses while minimising” the drugs required. This reduces costs and off-target side effects.
“DoriVac also has numerous advantages over other nanoparticle platforms, including targeting to specific compartments within cells and co-delivering multiple types of molecules to desired targets at the lowest possible doses.”
The “core component” of DoriVac is a “self-assembling square block-shaped nanostructure”. On one face of the block, defined numbers of adjuvant molecules can be attached in “highly tunable, nanoprecise patterns”, with the opposite face binding tumour antigens.
In study
The study, which is not open access, identified that molecules of the CpG adjuvant spaced exactly 3.5 nanometres apart resulted in the “most beneficial stimulation of APCs” that induced a “highly desirable profile of T cells”. The adjuvant is a synthetic strand of DNA comprising repeated CpG nucleotide motifs that “mimic the genetic material from immune cell-invading bacterial and viral pathogens”. It binds to a “danger receptor” called TLR9, which induces an inflammatory response that “works in concert” with the antigen-induced response.
First author Dr Yang (Claire) Zeng commented that previous work highlighted the importance to TLR9 receptors dimerising and aggregating into multimeric complexes binding to multiple CpG molecules.
“The nanoscale distances between the CpG-binding domains in effective TLR9 assemblies revealed by structural analysis fell right into the range of what we hypothesised we could mirror with DNA origami structures presenting precisely spaced CpG molecules.”
Dr Zeng and the team were “excited” to find that the DoriVac vaccine “preferentially induced an immune activation state that supports anti-tumour immunity”, something that “researchers generally want to see in a good vaccine”.
As well as the spacing, the numbers of CpG molecules in DoriVac vaccines made a difference, with 18 providing the “best APC activation”. The key finding is that the observations “translated to in vivo mouse tumour models”. The vaccines, injected under the skin of mice prophylactically, accumulated in the closest lymph nodes to stimulate DCs. A vaccine loaded with a melanoma antigen prevented the growth of aggressive melanoma cells upon challenge.
Although the control animals “succumbed” to the cancer by day 42 of the experiment, DoriVac-protected animals were alive, and displayed inhibited tumour growth in mice that already had formed melanoma tumours. The team also investigated if DoriVac vaccines could boost immune responses produced by neoantigens in melanoma tumours. A DoriVac vaccine with four neoantigens enabled them to “significantly suppress growth of the tumour in mice that produced the neoantigens”.
The last test was if DoriVac could “synergise with immune checkpoint therapy”. The combination resulted in the “total regression” of melanoma tumours, and prevented recurrence when the animals were exposed to the same tumour cells four months later. Dr Zeng believes that “DoriVac’s value for determining a sweet spot in adjuvant delivery” and “enhancing the delivery and effects of coupled antigens” could “pave the way to more effective clinical cancer vaccines”.
Technology for the future
Dr William Shih, who led the team at the Wyss Institute with Dr Zeng, suggests that the DNA origami technology “merges different nanotechnological capabilities that we have developed over the years with an ever-deepening knowledge about cancer-suppressing immune processes”.
“We envision that in the future, antigens identified in patients with different types of tumours could be quickly loaded onto prefabricated, adjuvant-containing DNA origami to enable highly effective personalised cancer vaccines that can be paired with FDA-approved checkpoint inhibitors in combination therapies.”
Dr Donald Ingber, Founding Director of the Wyss Institute, states that the platform is “our first example of how our pursuit of what we call Molecular Robotics – synthetic bioinspired molecules that have programmable shape and function – can lead to entirely new and powerful therapeutics”.
“This technology opens an entirely new path for the development of designed vaccines with properties tailored to meet specific clinical challenges. We hope to see its rapid translation into the clinic.”
For more on innovative technology to revolutionise cancer immunotherapy do get your tickets to the Congress in April or subscribe to our newsletters here!
by Charlotte Kilpatrick | Feb 1, 2024 | Technology |
Researchers from MIT announced in January 2024 that they have created a vaccine that induces a “strong antibody response” against SARS-CoV-2 through a virus-like delivery particle made from DNA. The work, published in Nature Communications, shows their investigation of thymus-independent DNA origami as an “alternative material” for multivalent antigen display using the receptor binding domain (RBD) of the SARS-CoV-2 spike protein.
The team found that sequential immunisation of mice elicited protective neutralising antibodies “in a manner that depends on the valency of the antigen displayed” and T cell help. However, the immune sera do not contain boosted, class-switched antibodies against the DNA scaffold, which mean that DNA-VLPs offer a good alternative for particulate vaccine design.
P-VLPs
The authors state that protein-based virus-like particles (P-VLPs) have “emerged as an important material platform for multivalent subunit vaccines”, enabling the “rigid display” of TD antigens. They have been used to investigate the effect of valency on B cell activation in vivo, suggesting “early B cell activation and downstream humoral immune responses are improved for some antigens as valency increases”.
However, control over antigen valency in P-VLPs is “constrained to the constituent self-assembled protein scaffold subunits”, which creates a challenge for the investigation of antigen valency without changing the scaffold. On the other hand, if constant protein scaffold geometry is used, investigations are “limited to stochastically controlled antigen valency and spatial positioning”.
“Furthermore, protein-based scaffolds themselves are TD antigens that elicit humoral immunity. This potentially misdirects antibody responses from the target antigens of interest and might also lead to imprinting.”
A final challenge is that scaffold-directed immunological memory may result in “antibody-dependent clearance of the vaccine material”, which would limit sequential or diversified immunisations.
DNA origami
To tackle these challenges, the researchers have developed scaffolds that are made with DNA origami, a method that “offers precise control over the structure of synthetic DNA” and allows them to attach a “variety of molecules”, like viral antigens, at specific locations.
In this study, they found that when they added an antigen consisting of the receptor binding protein of the original strain of SARS-CoV-2, mice who received the vaccine generated high levels of antibodies to the spike protein but not the DNA scaffold. Associate Professor Daniel Lingwood suggests that the DNA nanoparticle “is immunogenically silent”.
An immunological trick
MIT states that the approach, which “strongly stimulates B cells”, could improve vaccine development for viruses that “have been difficult to target”. Associate Professor Lingwood commented that the team is interested in teaching the immune system to “deliver higher levels of immunity against pathogens that resist conventional vaccine approaches”.
“This idea of decoupling the response against the target antigen from the platform itself is a potentially powerful immunological trick that one can now bring to bear to help those immunological targeting decisions move in a direction that is more focused.”
A laser-focus
Professor Mark Bathe, MIT, describes how the DNA scaffold “does not elicit antibodies that may distract away from the protein of interest”.
“What you can imagine is that your B cells and immune system are being fully trained by that target antigen, and that’s what you want – for your immune system to be laser-focused on the antigen of interest.”
For more on vaccine technology for improved immune responses, join us at the Congress in Washington this April or subscribe to our weekly newsletters here!
