Characteristics to consider when selecting a positive control material for an in vitro assay

The use of in vitro assays to inform decision-making requires robust and reproducible results across studies, laboratories, and time. Experiments using positive control materials are an integral component of an assay procedure to demonstrate the extent to which the measurement system is performing as expected. This paper reviews ten characteristics that should be considered when selecting a positive control material for an in vitro assay: 1) the biological mechanism of action, 2) ease of preparation, 3) chemical purity, 4) verifiable physical properties, 5) stability, 6) ability to generate responses spanning the dynamic range of the assay, 7) technical or biological interference, 8) commercial availability, 9) user toxicity, and 10) disposability. Examples and a case study of the monocyte activation test are provided to demonstrate the application of these characteristics for identification and selection of potential positive control materials. Because specific positive control materials are often written into testing standards for in vitro assays, selection of the positive control material based on these characteristics can aid in ensuring the long-term relevance and usability of these standards.

Increasing the use of animal-free recombinant antibodies

Antibodies are used in a range of research, diagnostic, and regulatory applications. Traditional methods for producing such reagents involve the immunization of animals, which introduces variability into the methods that use them and is not aligned with efforts to replace and reduce animal use. Experts from academia, biotechnology, government, and animal protection organizations met December 3, 2019, at the National Institutes of Health in Bethesda, MD, USA to discuss the status of development and use of animal-free recombinant antibodies and their potential to replace antibodies derived from animals. This paper summarizes the discussion and the actions that resulted to facilitate increased production and use of animal-free recombinant antibodies.