Interaction of cholera toxin B subunit with T and B lymphocytes

: Navolotskaya EV, Sadovnikov VB, Zitichenko DV, Lipkin VM, Zav'yalov VP

Publisher: ELSEVIER SCIENCE BV

: 2017

: International Immunopharmacology

: INTERNATIONAL IMMUNOPHARMACOLOGY

: INT IMMUNOPHARMACOL

: 50

: 279

: 282

: 4

: 1567-5769

: 1878-1705

DOI: https://doi.org/10.1016/j.intimp.2017.07.011

We have prepared I-125-labeled cholera toxin B subunit (I-125-labeled CT-B, a specific activity of 98 Ci/mmol) and found that its binding to T and B lymphocytes from the blood of healthy donors was high-affinity (K-d 2.8 and 3.0 nM, respectively). The binding of labeled protein was completely inhibited by unlabeled thymosin-alpha(1) (TM-alpha(1)), interferon-alpha(2) (IFN-alpha(2)), and the synthetic peptide LKEKK that corresponds to residues 16-20 in TM-alpha(1) and 131-135 in IFN-alpha(2), but was not inhibited by the synthetic peptide KKEKL with inverted amino acid sequence (K-1 > 10 mu M). Thus, TM-alpha(1), IFN-alpha(2), 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 10-1000 nM increased in a dose-dependent manner the soluble guanylate cyclase activity in T and B lymphocytes.