2Institute of Molecular Genetics, Russian Academy of Sciences, 123182 Moscow, Russia; fax: +7 (495) 196-0221
3State Research Institute of Highly Pure Biopreparations, Federal Biomedical Agency, 197110 St. Petersburg, Russia; fax: +7 (812) 235-5504
* To whom correspondence should be addressed.
Received March 1, 2016; Revision received May 11, 2016
The synthetic peptide LKEKK corresponding to sequence 16-20 of human thymosin-α1 and 131-135 of human interferon-α2 was labeled with tritium to specific activity 28 Ci/mol. The [3H]LKEKK bound with high affinity (Kd = 3.7 ± 0.3 nM) to donor blood T-lymphocytes. Treatment of cells with trypsin or proteinase K did not abolish [3H]LKEKK binding, suggesting the non-protein nature of the peptide receptor. The binding was inhibited by thymosin-α1, interferon-α2, and cholera toxin B subunit (Ki = 2.0 ± 0.3, 2.2 ± 0.2, and 3.6 ± 0.3 nM, respectively). Using [3H]LKEKK, we demonstrated the existence of a non-protein receptor common for thymosin-α1, interferon-α2, and cholera toxin B-subunit on donor blood T-lymphocytes.
KEY WORDS: peptides, receptors, thymosin-α1, interferon-α, T-lymphocytes