Spinning for Answers: What Ultracentrifugation Reveals About Antibodies in Serum
By Veritas Innovation | August 2025
In the world of diagnostics and therapeutic development, understanding how antibodies behave in real human serum is critical. After all, that is the environment where they actually do their job or don’t.
A recent study published in the European Biophysics Journal by Correia et al. (2023) explored this very issue using a high-resolution technique called fluorescence detected sedimentation velocity analytical ultracentrifugation (FDS AUC). It sounds like a mouthful, but this post will break it down and show how our own Human Gamma Globulin Powder (HGG1000) fits naturally into this picture.
What’s the Big Idea
Correia and colleagues set out to study how a therapeutic monoclonal antibody, in this case golimumab (Simponi), behaves in pooled human serum. Human serum is a complex, high-protein fluid filled with IgG, IgM, albumin, and other molecules that can interact in surprising ways.
To track this, they used FDS AUC, a technique that combines high-speed spinning with laser detection to monitor how molecules move and interact in solution. By labeling golimumab with a fluorescent tag (Alexa-488), they could directly observe how it moved through serum and see what slowed it down or caused it to bind to other components.
What Did They Find
In plain terms, here is what they discovered:
Serum alone showed a strong presence of IgG and a notable boundary for IgM pentamers around 19 Svedbergs (S), a measurement of how fast something sediments during ultracentrifugation
They also detected a bilirubin–albumin complex that behaved unusually due to non-ideal conditions. In other words, the solution was so crowded with proteins that standard diffusion rules didn’t apply. This is known as the Johnston–Ogston (JO) effect
When golimumab was introduced as a fluorescent tracer, it showed a weak but reversible interaction with total human IgG (binding constant ~4,000 M⁻¹). In addition:
A 10.2 S complex was observed between golimumab and IgG
A 19 S complex was observed between golimumab and IgM pentamers
The takeaway is that in a serum-rich environment, therapeutic antibodies do not just float around. They bind, bounce, and interact in ways that can influence their bioavailability, efficacy, and immunogenicity.
Where Gamma Globulin Powder Comes In
Gamma globulins, particularly human IgG, are the very molecules that made this study so insightful. Correia’s team examined how these proteins interact with therapeutic monoclonal antibodies under realistic biological conditions.
If you are developing a diagnostic assay, validating an immunoassay, or setting up a control experiment, you want those same IgG interactions but in a controlled and reproducible format.
That is where Human Gamma Globulin Powder (HGG1000) comes in.
Use Cases for HGG1000
Matrix Simulation: Recreate a protein-rich, IgG-dominant environment to mimic serum complexity during assay development
AUC and Binding Studies: Serve as a well-characterized IgG source for sedimentation velocity or interaction experiments, just like the ones in the study
Control Material: Use in ELISAs, immunoassays, or as a negative or positive control in therapeutic antibody testing
Standardization: Batch-to-batch consistency ensures you get repeatable results every time
By providing purified, highly consistent gamma globulin from human plasma, HGG1000 enables researchers to explore antibody behavior without the variability of pooled serum samples.
Quick Glossary
| Term | Plain English Definition |
|---|---|
| FDS AUC | A method that spins samples very fast while using a laser to track where molecules go. Ideal for watching interactions |
| Svedberg (S) | A unit that tells us how fast something settles during ultracentrifugation. Bigger or faster molecules have a higher S value |
| Non-ideality | Real-life complexity in solutions when molecules get crowded and do not behave as neatly as expected |
| JO Effect | When slower molecules like IgG block faster ones, disrupting sedimentation patterns similar to traffic congestion at the microscopic level |
Bottom Line
This study is more than just centrifuge science. It offers valuable insight into how biologics behave in the body. And whether you are validating a test or fine-tuning an assay, having access to reliable, purified human gamma globulin gives you a clear advantage.
At Veritas Innovation, we are proud to offer HGG1000 Human Gamma Globulin Powder as a dependable tool for researchers, assay developers, and quality control teams who need a consistent source of human IgG.
Because sometimes, understanding how antibodies behave starts with giving them the right crowd to swim in.
Reference
Correia, J. J., Bishop, G. R., Kyle, P. B., Wright, R. T., Sherwood, P. J., & Stafford, W. F. (2023). Sedimentation velocity FDS studies of antibodies in pooled human serum. European Biophysics Journal. https://doi.org/10.1007/s00249-023-01652-1