Culture development

Dominic Eisinger discusses an easy, reliable and cost-effective solution to immune system monitoring in clinical trials.

TruCulture is Rules-Based Medicine's proprietary blood culture system that provides reliable monitoring of the immune system in clinical trial applications. When combined with RBM's comprehensive panel of 46 cytokine and chemokine immunoassays (TruCultureMAP v1.0), TruCulture can provide valuable insight into how a disease or therapy affects an individual's immune status.

Using TruCulture, the immune system can be readily sampled within a standard blood collection tube. TruCulture maintains all cellular components throughout culture, which is an advantage when probing the immune system outside of the body (ex vivo). Minimizing sample manipulation is important as exemplified by the variability and high failure rates seen with blood transported to central labs for peripheral blood mononuclear cells (PBMCs) cultures. By instantly mixing whole-blood with media, stimulants and or test substances in an enclosed sterile environment, TruCulture has an extremely low failure rate.

TruCulture is the first standardised, fully closed, whole-blood culture system developed for the clinical setting that does not require cell culture facilities or specialised personnel. The system incorporates a three ml blood collection tube containing cell culture media optimised for this purpose which can contain test substances such as drug candidates, drug metabolites or immune modulators. Blood is drawn by standard phlebotomy directly into the collection tube media for an immediate and controlled initiation of whole-blood cell culture. After incubation overnight in a 37⁰ C heating block, blood cells are physically separated from the culture media by insertion of a valve separator. The culture media can be stored and shipped frozen for analysis of signalling proteins and high-quality, non-degraded RNA can be obtained from the cells for gene expression analysis.

Probing the immune system with whole blood is reliable and consistent as all of the key elements of the immune system including cellular (granulocytes - neutrophils, basophils, eosinophils, lymphocytes, monocytes, NK-cells), pseudo-cellular (red blood cells, platelets), and subcellular components (such as enzyme inhibitors, complement system and kininogens) are present. Both innate and adaptive immune system responses can be measured with TruCulture. The reproducibility of TruCulture now allows one to assess an individual's immune status before and after introduction of the experimental portion of the protocol.

Common applications for TruCulture in the drug development setting are drug safety, drug efficacy and pharmacodynamics (PD). An example of a safety application would be the Tegenero incident in 2006 when a CD28 superagonistic antibody (TGN1412) was administered to healthy phase I volunteers. Within minutes, a single intravenous dose induced a systemic cytokine storm leading to multiple organ failure. All of the young men survived this life-threatening event. The biologic in question had been tested in both rats and monkey with little indication that at its given dose it had a safety issue. It would have been preferable to test this biologic in the safe and controlled environment of an ex vivo study, such as TruCulture.

Pharmacodynamic biomarker discovery with TruCulture in phase I trials can also be a valuable tool. As the complexity of the immune system is guided by soluble mediators such as cytokines and chemokines, it is not surprising to find that the expression of such mediators can correlate directly or indirectly with drug mechanism of action. In subsequent validation studies, these candidate biomarkers may become import for understanding drug efficacy or useful for patient stratification.

TruCulture makes ex vivo immune monitoring in clinical trials possible and can facilitate a successful biomarker strategy by interrogating a large number of targets thus identifying patterns on which to focus further research. By applying multiplexing technology, the RBM approach provides drug developers and researchers with a cost-effective and reproducible way to measure dozens of relevant clinical markers and to pinpoint the biomarker patterns that are involved either directly in the disease process or are useful surrogates. When these patterns can be reliably measured, the efficiency of drug development is greatly accelerated.

Dominic Eisinger is the Director of Strategic Development for Rules-Based Medicine (RBM). He joined in 2006 as part of the business and scientific management team. He is a noted international authority on protein arrays and prior to joining RBM, he was President of Multiplex Biosciences, a multiplex immunoassay services company. He received his PhD in stem cell molecular biology in 1994.