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Off-the-shelf reagent for influenza vaccine development
Home » Vaccine Development » TiterSafe for Easy HAI Assays
When you need to grow live influenza virus for hemagglutination inhibition (HAI) assays, it means moving other key tasks to the back burner. It also means exposing team members to occupational health risks.
With TiterSafeTM, you can get straight to work testing immune sera. The first product of its kind, TiterSafe is an off-the shelf reagent that can easily substitute for live virus in your existing agglutination assays.
Free from the chore of growing virus stocks, your team will have more time to focus on important science. Plus, because TiterSafe is non-replicative, your lab team will be safer.
TiterSafe consists of membrane-wrapped particles with a lentivirus core. Its hemagglutinin (HA) and neuraminidase (NA) surface proteins have amino acid sequences identical to those from specific strains of influenza A or influenza B virus. TiterSafe has many advantages over live influenza virus in HAI assays.
Advantages
✔ Ready-to-use, quality controlled reagent
✔ Non-replicative & safe for BSL-2
✔ Easy to substitute in your existing assays
✔ Available for seasonal & custom strains
“SARS-CoV-2 RVPs really helped us a lot since we did not have much previous expertise in SARS. The user meetings were especially helpful.”
-YUFEI XIANG, UNIVERSITY OF PITTSBURGH SCHOOL OF MEDICINE
TiterSafe is available now for seasonal* and pandemic influenza strains. New TiterSafe products will be released as new seasonal and pandemic strains are announced.
* WHO-recommended strains for cell-based/recombinant vaccines
Catalog No. | Virus (Subtype) | Strain Information |
---|---|---|
HAP-1214 | Influenza A (H5N1) | American Wigeon/SC/22-000345-001/2021 |
HAP-1302 | Influenza B (Victoria) | Austria/1359417/2021 |
HAP-1303 | Influenza B (Yamagata) | Phuket/3073/2013 |
HAP-1212 | Influenza A (H3N2) | Darwin/6/2021 |
HAP-1213 | Influenza A (H1N1) | Wisconsin/67/2022 |
Related product: Influenza Reporter Virus Particles (RVPs) for safe, easy neutralization assays are available with a GFP or luciferase reporter gene. Influenza RVPs are available in seasonal and pandemic strains; see the Reporter Virus Particle Catalog for details.
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TiterSafe is a flexible reagent that can be used in a variety of influenza assays, including HA, HAI, and NA ELLA assays.
TiterSafe is based on our highly validated platform for building pseudotyped Reporter Virus Particles. TiterSafe is produced in human cells using transfected DNA encoding the influenza HA and NA proteins. Its HA and NA surface proteins have amino acid sequences identical to those in live virus.
TiterSafe’s HA and NA surface proteins show the expected interactions and activities. In HAI assays with both sera and MAbs, TiterSafe shows the expected specificity for strain and lineage.
Because TiterSafe is not amplified by replication, the HA on the surface is the same on every particle and in every tube of reagent. Unlike with live virus, there is no sequence drift.
Due to its modular design, TiterSafe is flexible and highly customizable. By swapping out the DNA sequences, we can quickly and easily make TiterSafe product lines for new and custom influenza strains.
In HA and HAI assays, TiterSafe performs like live influenza virus by cross-linking red blood cells (RBCs). This cross-linked matrix is visible to the eye as a broad red area spread across the sample well. In the absence of cross-linking, or agglutination, the RBCs form a concentrated spot at the bottom of the well.
As with live virus, you can use TiterSafe to detect agglutination-inhibiting antibodies in vaccine sera, and thus estimate the level of protection against influenza virus. When specific antibodies bind to TiterSafe surface proteins, they block agglutination, and the RBCs form a concentrated spot.
TiterSafe is an easy and safe substitute. It fits into conventional HAI workflows as a straight replacement for live influenza virus. It provides accurate HAI assay results, ensuring that your research remains reliable and valid.
Because TiterSafe has a much better safety profile than live influenza virus, it can be easier to work with. It is non-replicative and safe in a BSL-2 environment.
To hear our customers describe how they have used TiterSafe, view the webinar Innovative Research Tools to Combat Biological Threats
Visit the Resources page for more webinars, publications, and case studies featuring additional virology products and services.
Because strains can behave differently in the lab, it’s difficult to put a timeline on the development of new products. However, we can produce TiterSafe as fast as or faster than live virus. We aim to have new TiterSafe seasonal influenza strains available within 8-10 weeks of the seasonal strain sequence releases for the recommended Northern and Southern hemisphere strains.
Keep in mind that TiterSafe is concentrated and ready to use. That means that once TiterSafe arrives in your hands, you can start work in lab. There is no growing of banking of virus required.
TiterSafe is similar to Influenza Reporter Virus Particles (RVPs), but it lacks a reporter gene, and it is more concentrated.
Due to the similarities between the platforms we use to make the two products, we can provide matched reagents with the same surface proteins and overall structure: RVPs for neutralization assays, and TiterSafe for HAI assays.
While the concentration does vary somewhat between lots and product lines, TiterSafe always has sufficient titer to replace live virus in assays. Each tube of product meets the following minimum specifications:
Lot characteristics and recommended input volumes are included with product shipments.
For example product sheets and protocols, please contact us.
We have worked with more than 100 top biotech and pharmaceutical companies to help them succeed. Let’s talk about how we can help you.
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