Minimal activity, typical activity, or lot-specific activity – the biological activity of recombinant cytokines may be stated to different degrees of accuracy. Read through this page and find out which values you can rely on for accurate cost calculation.
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The biological activity can be specified in three different formats. Depending on the context, all are useful – it is however very important to not confuse them with each other. Whenever possible, we provide these three parameters.
The minimal activity is by definition lower than the typical activity of a cytokine. Often, these two values are significantly different. Thus, calculating the needed number of vials based on the stated minimal activity will almost always overestimate the costs associated with a project. Minimal activity should therefore only be used to calculate cytokine costs when no other activity parameter is available.
The typical activity of MACS GMP Cytokines is on average 2.7× higher than the stated minimal activity. Calculating the necessary number of vials based on minimal activity will therefore considerably overestimate reagent costs.
A simple calculation shows the difference: In this example project, 1x107 IU MACS GMP IL-2 are required. Calculations based on the stated minimal activity estimate 100 vials needed versus 20 vials needed based on typical activities. In this specific example, cost calculation would be 80% overestimated when calculated based on minimal cytokine activities.
Cytokine dosing based on lot-specific biological activity alleviates challenges caused by batch-to-batch variations and will reduce experimental variability significantly. However, batch-to-batch variation can be problematic when managing supply chain, logistics, and expenditures.
For smaller projects using only a single batch of cytokine, calibrated lot-specific activity is the most accurate parameter on which to base cost calculations. However, in long-term projects where several different cytokine batches are consumed, batch-to-batch variations can result in varying cytokine costs. Therefore, for long-term projects not the lot-specific activity of one single cytokine batch, but rather the average lot-specific activity of multiple batches (the so called “typical activity”) is the optimal choice to calculate costs.
The exemplary calculation shows that cost calculations based on the lot-specific activity of a batch with a lower-than-average activity (batch A) will result in overestimation of costs for a long-term project, in which cytokines of several production lots will be applied.
In long-term projects, cytokines from different batches might be purchased. As shown in the graph, the lot-specific activities of the different batches vary, while the cumulated average activity of all batches quickly converges with the stated typical activity. The larger the project, the more exact the values derived from the typical activity will be.
Calculations using the stated typical activity will yield good estimations of total costs for long-term projects. However, at a single point in time or for smaller projects – when a cytokine lot with an activity that deviates from the typical activity is purchased – the costs can vary from the costs calculated using the typical activity.
These examples highlight, that overall, a low batch-to-batch variability is desirable. Although the total cytokine costs will be close to the costs calculated with the typical activity, a high batch-to-batch variability will result in a high fluctuation of cytokine costs over time.
To facilitate accurate cost calculations and to avoid large fluctuations in cytokine costs, both a realistic assumption of the typical activity of a specific cytokine and a low batch-to-batch variability is required.
We at Miltenyi Biotec value your specific project needs. To offer maximal transparency, we are currently updating our product pages to give you the information you need to decide if MACS GMP Cytokines are the perfect choice for your project. We will display the typical biological activity on the product pages of MACS GMP Cytokines. This table below gives a first overview for selected cytokines.
Typical cytokine activity of MACS GMP Cytokines
|Cytokine||Activity (IU or U/mg)|
Minimal and typical activity of selected MACS GMP Cytokines.
We will display representative data of the batch-to-batch variability and the historically observed activity range of our MACS GMP Cytokines on the respective product pages, whenever available. This allows for better estimation of the biological activities to be expected.
MACS GMP Cytokines offer a consistently low batch-to-batch variation. The graph gives an overview for selected cytokines.
Download our application notes to get some background information and guidance on what to consider when choosing GMP-compliant cytokines that fit your purpose best.
Cytokine testing can be a complicated and expensive process. If you need help, simply fill out the form below to get in contact with our cytokine experts. They will introduce you to the tricks which can help you to reduce costs and streamline the process.
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