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Recombinant Albumin as a Carrier Protein Improves Cytokine Recovery and Functional Stability at Dilute Concentrations

Published on 12 January 2026

Application Note

Authors: Jacob Weber, PhD, Vice President of Process Development, Mark Stathos, PhD, Applications Scientist, Marcus Curl, Vice President of Product Applications, Andy Su, Quality Control
Analyst, and Rupesh Shrestha PhD, Process Development Scientist.
InVitria, Inc., USA

Audio Summary: Optibumin 25 Stabilizes High-Cost Cytokines

Overview

This application note evaluates the use of Optibumin® 25, a recombinant, animal-origin-free human serum albumin (rHSA), as a carrier protein to stabilize dilute cytokine formulations commonly used in cell culture and cell therapy workflows.
The study demonstrates that Optibumin 25 significantly improves cytokine recovery by reducing losses due to aggregation and surface adsorption, while preserving functional bioactivity during refrigerated and room-temperature storage.

Compared to albumin-free formulations, cytokines stabilized with Optibumin 25 showed higher monomer recovery and maintained EC50 values, performing comparably to plasma-derived HSA without the associated risks of donor variability or viral contamination. These findings support more consistent cytokine handling, storage, and use in cytokine-dependent cell culture and cell therapy applications.

Key Findings

  • Improves recovery of dilute cytokine formulations by reducing aggregation and surface adsorption losses
  • Preserves cytokine bioactivity (EC50) after refrigerated (2–8°C) and room-temperature storage
  • Supports functional stability of cytokines for up to 4 weeks at room temperature under tested conditions
  • Performs comparably to plasma-derived HSA without donor variability
  • Animal-origin-free, recombinant albumin suitable for regulated cell therapy workflows

Featured Solution

Optibumin 25 – Recombinant Human Serum Albumin, 25% Solution – Animal-Origin-Free, GMP-Produced

Optibumin 25 is a chemically defined, recombinant human serum albumin designed to stabilize sensitive biologics, including cytokines and growth factors, used at low concentrations. Its high purity, high free-thiol (Cys34) content, and stabilizer-free formulation help reduce aggregation, adsorption, and oxidative degradation that compromise cytokine performance. As a plasma-free alternative to human serum albumin, Optibumin 25 supports more consistent cytokine recovery and preserved biological activity, while reducing regulatory and supply-chain risks associated with blood-derived materials. It is well suited for cell therapy, immunotherapy, and cytokine-dependent cell culture applications.

Learn more about Optibumin 25

 

Frequently Asked Questions (FAQs)

Q: Why do cytokines lose activity at low concentrations?
A: Cytokines are highly potent proteins typically used at microgram- or nanogram-per-milliliter concentrations. At these dilutions, they are especially prone to surface adsorption, aggregation, and oxidative degradation, leading to reduced recovery and loss of biological activity over time.

Q: How does Optibumin® 25 improve cytokine stability?
A: Optibumin 25 acts as a carrier protein that reduces non-specific adsorption to containers, limits aggregation, and provides antioxidant protection through its free-thiol (Cys34) residue. This helps preserve both physical recovery and functional bioactivity of dilute cytokine formulations.

Q: How does recombinant albumin compare to plasma-derived HSA for cytokine stabilization?
A: In this study, Optibumin 25 performed comparably to plasma-derived HSA in preserving cytokine recovery and bioactivity, while eliminating donor-to-donor variability and residual viral risk associated with blood-derived materials.

Q: Does Optibumin® 25 support room-temperature storage of cytokines?
A: Yes. Cytokines formulated with Optibumin 25 maintained functional bioactivity for up to four weeks at room temperature under the conditions evaluated in this study, reducing sensitivity to handling and temperature excursions.

Q: What applications benefit most from cytokine stabilization with Optibumin® 25?
A: This approach is particularly relevant for cytokine-dependent workflows such as cell therapy manufacturing, T-cell immunotherapy, immune cell expansion, and other cell culture applications where consistency and bioactivity of cytokines are critical.

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Footnotes

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