Authors
Daria Menshikova, Alexey Terentiev, Pavel Ivanov, Alexandr Cherednichenko, Liubov Beduleva
Published in
Antibodies (Basel, Switzerland). Volume 15. Issue 5. Oct 19, 2026. Epub Oct 19, 2026.
Abstract
Regulatory rheumatoid factor (regRF) is a recently discovered population of natural anti-idiotypic antibodies carrying a shared paratope specific to the PD-1 molecule. Normally, regRF exerts a cytotoxic effect on PD-1-expressing T lymphocytes, including autoreactive ones, thereby controlling their expansion. The specificity for PD-1 indentifies regRF as a promising therapeutic agent for suppressing autoimmune reactions via the PD-1 pathway. The aim of this study was to develop gentle methods for regRF isolation from healthy blood plasma, which would preserve the bioactivity of regRF.
Ammonium sulfate precipitation was used for crude regRF purification. A search for suitable affinity sorbents was carried out. The purified regRF was tested for its bioactivity.
Ammonium sulfate precipitation at 35% saturation, followed by extraction with 28% saturated ammonium sulfate solution, allowed the separation of regRF from a portion of non-target IgG and high-molecular-weight fibrinogen. RegRF showed high affinity for Cibacron Blue and no binding to Protein A. Sequential affinity chromatography on immobilized Cibacron Blue and Protein A enabled the purification of regRF from non-target immunoglobulins and low-molecular-weight fibrinogen. The purified regRF samples showed binding to PD-1 and reduced the PD-1+CD4+ T lymphocyte count in vitro.
Thus, we have identified sorbents and conditions for the purification of biologically active regRF.
PMID:
42930040
Bibliographic data and abstract were imported from PubMed on 26 Oct 2026.
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