Creative Biolabs

Cytokine Release Assay

Cytokine Release Assay

Cytokine release assays (CRA) have become risk identification and prospective risk assessment tools for screening novel biotherapeutics agents that may induce adverse proinflammatory clinical infusion responses. Creative Biolabs’ goal is to commercialize its proprietary technology and engage with one or more corporate partners in the biopharmaceutical industry. We will work with you as part of your team to not only provide you with comprehensive high-quality data but also provide timely and effective solutions to any challenges you face in CRA.

Overview of CRA

Cytokine release syndrome (CRS) is a potentially adverse clinical event in which immune cells release pro-inflammatory cytokines (such as TNF-α, IL-6, IL-8, IFN-γ, etc.) CRA is in vitro assay using human cells in the preclinical setting as a means to predict the potential for a new biotherapeutic to induce significant cytokine release from immune cells in vivo. CRA formats include in solution (drug in solution or water phase), direct fixation on plastic using a "dry coating" or "wet coating" method (solid phase), indirect fixation by Fc-capture, or presentation in a "co-culture" environment involving the presentation of test antibodies in immune cells and other cell types. CRA using human peripheral blood mononuclear cells (PBMC) has become common in vitro detection system to predict the risk of clinically relevant CRS.

Different Cytokines Can be Measured at Creative Biolabs

The cytokines most commonly measured include interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-8 (IL-8), however, some laboratories extend this panel by including IL-1β, IL-2, IL-5, IL-10, IL-12, and IL-17. Although high levels of IL-2 and IFN-γ release are hallmarks of TGN-1412-like response, the selection of cytokines should specifically be adapted dependent on the individual target molecule, the cell populations targeted, and the drug mode of action.

CRA Platform in Creative Biolabs

Several different detection platforms have been introduced as non-clinical risk assessment systems, including liquid-phase, air-drying solid-phase, and wet-coating solid-phase methods.

  • Multiplex Technology

The advent of multiplex technology has allowed the measurement of multiple cytokines simultaneously. The commonality of existing technologies is that all platforms use high-affinity to capture antibodies binding to stromal-derived cytokines, but there are differences in expression and detection. These platforms fall into two broad categories: plate-based technology which fixes captured antibodies in pores and read them using a plate reader, and bead-based technology in which antibodies are presented on the bead and read using flow cytometry or variants thereof.

  • Soluble Phase CRA

The predominantly used CRA uses variations of the solution phase assay either with blood or PBMCs. The whole blood assay has been a valuable tool to detect cytokine release to some biotherapeutics. Since variability in results includes variability in white blood cell counts from donor to donor, it may be useful to assess white blood cell counts using a hematology analyzer in data interpretation. Cytokines released are usually measured using multiple immunoassays.

  • Solid Phase CRA

The most commonly used solid phase format within the pharmaceutical industry involves PBMC in combination with the biotherapeutics presented after overnight dry-coating on the bottom of 96-well plates. The solid-phase method is commonly used to detect the risk of CRS due to mAb.

Commonly used CRA formats.Fig.1 Commonly used CRA formats. (Liu, 2022)

Although not mandatory, CRA testing is widely expected by regulators to be based on a scientific assessment of potential risks, and many laboratories now routinely perform analyses. Given the complexity of mechanisms and target characteristics by which drugs induce cytokine release, Creative Biolabs has developed many different formats of CRA. We are flexible to meet the unique needs of CRA projects. Please do not hesitate to contact us for advancing your research projects.


  1. Liu, J. Development of Cytokine Release Assay as a Prediction of Immunosafety. 2022.
For Research Use Only. Not For Clinical Use.
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