Interaction of cholera toxin B subunit with T and B lymphocytes

Publication date: September 2017
Source:International Immunopharmacology, Volume 50
Author(s): Elena V. Navolotskaya, Vladimir B. Sadovnikov, Dmitry V. Zinchenko, Valery M. Lipkin, Vladimir P. Zav'yalov
We have prepared ¹²⁵I-labeled cholera toxin B subunit (¹²⁵I-labeled CT-B, a specific activity of 98Ci/mmol) and found that its binding to T and B lymphocytes from the blood of healthy donors was high-affinity (Kd 2.8 and 3.0nM, respectively). The binding of labeled protein was completely inhibited by unlabeled thymosin-α1 (TM-α1), interferon-α2 (IFN-α2), and the synthetic peptide LKEKK that corresponds to residues 16–20 in TM-α1 and 131–135 in IFN-α2, but was not inhibited by the synthetic peptide KKEKL with inverted amino acid sequence (Ki>10μM). Thus, TM-α1, IFN-α2, and the peptide: LKEKK bind with high affinity and specificity to CT-B receptor on donor blood T and B lymphocytes. It was found that CT-B and the peptide: LKEKK at concentrations of 10–1000nM increased in a dose-dependent manner the soluble guanylate cyclase activity in T and B lymphocytes.

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